42 entries found for : it-15
Ngo M, Han A, Lakatos A, Sahoo D, Hachey S, Weiskopf K, Beck A, Weissman I, Boiko A (2016) Antibody therapy targeting CD47 and CD271 effectively suppresses melanoma metastasis in patient-derived xenografts. Cell Rep 16:1701-1716. doi: 10.1016/j.celrep.2016.07.004
Summary: The high rate of metastasis and recurrence among melanoma patients indicates the presence of cells within melanoma that have the ability to both initiate metastatic programs and bypass immune recognition. The authors identified CD47 as a regulator of melanoma tumor metastasis and immune evasion. The study involved antibody-mediated blockade of CD47 coupled with targeting of CD271+ melanoma cells by way of ME20.4-SAP (Cat. #IT-15). Mice bearing human melanoma tumor (M213 or M727) were randomized into four treatment groups with one of those groups receiving treatment with ME20.4-SAP. 1 ug in 50 ul volumes were injected directly into the center mass of the tumor once every 2 days. A therapeutic effect was observed where tumor metastasis in patient-derived xenografts was strongly inhibited when treated with the combination of antibody-mediated blockade of CD47 and targeted with ME20.4-SAP.
Related Products: ME20.4-SAP (Cat. #IT-15)
The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex.
Bajo V, Leach N, Cordery P, Nodal F, King A (2014) The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex. Eur J Neurosci 40:2922-2940. doi: 10.1111/ejn.12653
Summary: The ferret has become a more common animal model in auditory neuroscience. Unlike rodent models, however, anatomical data describing the organization of the basal forebrain cholinergic system and its projections to the auditory cortex have not been well characterized. Using a variety of methods the authors mapped the architecture of the ferret basal forebrain. IHC was done with several antibodies including anti-ChAT (Cat. #AB-N34AP; 1:1000) and anti-NGFr (Cat. #AB-N07; 1:500). Animals also received 17 μg of ME20.4-SAP (Cat. #IT-15) in a total of 17 injections into the ectosylvian gyrus. The results indicate that acetylcholine is most likely involved in modulation of auditory processing.
Related Products: Choline Acetyltransferase Rabbit Polyclonal, affinity-purified (Cat. #AB-N34AP), NGFr (ME20.4, p75) Mouse Monoclonal (Cat. #AB-N07), ME20.4-SAP (Cat. #IT-15)
Nodal FR, Leach ND, Keating P, Dahmen JC, King AJ, Bajo VM (2013) Spatial processing in the primary auditory cortex following cholinergic lesions of the basal forebrain in ferrets. Neuroscience 2013 Abstracts 353.09. Society for Neuroscience, San Diego, CA.
Summary: Cortical acetylcholine release has been implicated in different cognitive functions, including perceptual learning. We have recently shown that cortical cholinergic innervation is necessary for normal sound localization accuracy in ferrets, as well as for their ability to adapt with training to altered spatial cues (Leach et al., 2013, J Neurosci 33:6659-71). To explore whether these behavioral deficits are associated with changes in the spatial sensitivity of cortical neurons, we recorded neural activity in the primary auditory cortex (A1) from three animals in which cholinergic inputs had previously been reduced by making bilateral injections of the immunotoxin ME20.4-SAP in the nucleus basalis (NB). Neural activity was recorded from 146 penetrations in the left and right A1 under anesthesia (medetomidine/ketamine) using Neuronexus multi-site silicon probes. Histological analysis after the recording sessions revealed a mean loss of cholinergic neurons in the NB of 89.3±7.1% when compared to control animals, as well as a significant reduction in cholinergic fiber density across the auditory cortex, including the middle ectosylvian gyrus where A1 is located. On the basis of the location of the penetrations and electrophysiological characterization of the neural responses, which typically exhibited a mean latency of ≤20 ms, frequency tuning and onset responses with occasional weaker offset responses, we were able to assign the recordings to A1. The distribution of unit best frequencies was used to ensure that the tonotopic axis of A1 was evenly sampled. Spatial tuning was determined using virtual acoustic space stimuli comprising 200 ms broadband noise presented at three different levels (56, 70 and 84 dB SPL) from 12 locations separated by 30° in azimuth. Most of the units were broadly tuned, responding to all the virtual sound locations tested. Their spatial preferences were quantified by calculating the centroid direction vector from the variation in spike count with stimulus location within the onset response. This revealed a contralateral preference for most units, with the majority of the centroid azimuths located within the frontal hemifield. These data are consistent with the distribution of azimuth tuning previously described in the ferret, and initial comparisons with control animals have not shown any differences in spatial sensitivity in the animals with cholinergic lesions. Reduced cholinergic release therefore does not appear to influence the spatial response properties of A1 neurons in anesthetized animals, suggesting that any effects on sensory coding may only become apparent during behavior.
Related Products: ME20.4-SAP (Cat. #IT-15)
Leach ND, Nodal FR, Cordery PM, King AJ, Bajo VM (2013) Cortical cholinergic input is required for normal auditory perception and experience-dependent plasticity in adult ferrets. J Neurosci 33(15):6659-6671. doi: 10.1523/JNEUROSCI.5039-12.2013
Summary: In order to study how cholinergic input from the nucleus basalis affects auditory perception and learning, the authors injected a total of 35.2 ng of ME20.4-SAP (Cat. #IT-15) into the nucleus basalis in each hemisphere of ferrets. Based on several learning tasks, the data suggest that these cholinergic inputs aid in the perception of sound source location and aid in the adaptation of the auditory system to changes in spatial cues.
Related Products: ME20.4-SAP (Cat. #IT-15)
Acetylcholine facilitates recovery of episodic memory after brain damage.
Croxson PL, Browning PG, Gaffan D, Baxter MG (2012) Acetylcholine facilitates recovery of episodic memory after brain damage. J Neurosci 32(40):13787-13795. doi: 10.1523/JNEUROSCI.2947-12.2012
Summary: Episodic memory is controlled by several interconnected brain structures. The order in which these structures sustain damage can affect the processes lost. In this work the authors performed numerous bilateral injections of ME20.4-SAP (Cat. #IT-15) into the infero-temporal cortex, the medial surface of the temporal lobe, the perirhinal and entorhinal cortex, and the temporal pole of monkeys. These injections totaled 2.2-2.5 μg of conjugate. The results indicate that loss of cortical acetylcholine function will interfere with adaptation to memory impairments caused by structural damage in episodic memory centers.
Related Products: ME20.4-SAP (Cat. #IT-15)
Cholinergic modulation of a specific memory function of prefrontal cortex.
Croxson PL, Kyriazis DA, Baxter MG (2011) Cholinergic modulation of a specific memory function of prefrontal cortex. Nat Neurosci 14(12):1510-1512. doi: 10.1038/nn.2971
Summary: The authors investigated loss of acetylcholine in the large and highly differentiated PFC's of rhesus monkeys. The monkeys received 80-92 20-ng injections of ME20.4-SAP (Cat. #IT-15) per hemisphere. Lesioned animals were severely impaired on tasks involving spatial working memory.
Related Products: ME20.4-SAP (Cat. #IT-15)
The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex
Bajo Lorenzana VM Leach ND, Cordery PM, Nodal FR, King AJ (2011) The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex. IBRO 2011 Abstracts International Brain Research Organization, Florence, Italy.
Summary: Projections from the NB to the auditory cortex were investigated by injecting tracers into the NB itself (n=5), or by applying tracer deposits to the surface of the auditory cortex (n=4). Tracers included Rhodamine, Fluorescein, Cascade Blue, as well as the cholinergic immunotoxin ME20.4-SAP. Both ME20.4-SAP injections in the auditory cortex and epipial tracer deposits revealed that NB provides the main cholinergic input to the cortex, and that this projection is predominantly ipsilateral.
Related Products: ME20.4-SAP (Cat. #IT-15)
Croxson PL, Baxter MG (2009) Multiple neuromodulator depletion interacts with fornix transection to impair episodic memory in monkeys. Neuroscience 2009 Abstracts 98.4/EE128. Society for Neuroscience, Chicago, IL.
Summary: Acetylcholine may play an important role in some aspects of cognitive function, and in particular in episodic memory. However, the role of other neuromodulatory (NM) substances, such as noradrenaline, dopamine, and serotonin, in episodic memory is less well-defined. We tested monkeys on a model of episodic memory in monkeys and carried out specific depletions of different neuromodulators within inferotemporal cortex (IT). Six rhesus macaque monkeys (five male) were trained on an object-in-place scene learning task that models key features of human episodic memory, because learning occurs rapidly (often in a single trial) in the contaxt of unique background scenes. After preoperative testing three monkeys were given injections into IT of the immunotoxin ME20.4-saporin interleaved with injections of 6-hydroxydopamine and 5,7-dihydroxytryptamine. This resulted in depletion of acetylcholine, dopamine, noradrenaline and serotonin throughout IT (group NM+ACh). Three monkeys received the same treatment but omitting the ME20.4-saporin, thus depleting dopamine, noradrenaline and serotonin, but sparing acetylcholine (group NM). Neither group of monkeys (NM+ACh or NM) were impaired in postoperative scene learning. We found previously that addition of fornix transection to depletion of ACh from IT severely impaired scene learning relative to fornix transection alone (Browning et al. 2009, Cerebral Cortex). Therefore we gave each monkey in groups NM and NM+ACh a bilateral fornix transection and performed a further postoperative performance test. As expected, monkeys in group NM+ACh were severely impaired in scene learning following fornix transection. However, monkeys in group NM were also severely impaired in scene learning following fornix transection, despite having no visible damage to cholinergic innervation. Depletion of cholinergic, dopaminergic, adrenergic and serotoninergic innervation of inferotemporal cortex, therefore, is not sufficient to impair monkeys' performance on an episodic memory task. Furthermore, there is a synergistic interaction between the NM depletion and fornix transection in this task, like that between ACh depletion and fornix transection. This may be due to a general reduction in cortical function after NM depletion, albeit not sufficient to cause episodic memory impairment on its own, which exacerbates the effect of fornix transection. It may point to one or more of these neuromodulators having a role in post-lesion plasticity, a role that is also played by ACh. Importantly, these data suggest that intact cholinergic innervation is not sufficient for post-lesion plasticity.
Related Products: ME20.4-SAP (Cat. #IT-15)
Browning PG, Gaffan D, Croxson PL, Baxter MG (2010) Severe scene learning impairment, but intact recognition memory, after cholinergic depletion of inferotemporal cortex followed by fornix transection. Cereb Cortex 20(2):282-293. doi: 10.1093/cercor/bhp097
Summary: In this work the authors investigated the link between connections carried by the fornix and cholinergic input to the inferotemporal cortex in scene learning. Monkeys received 56-64 0.02-µg injections of ME20.4-SAP (Cat. #IT-15) into the inferotemporal cortex, and entorhinal cortices. There was a marked impairment in memory for lesioned animals that also received a fornix transection, indicating a synergistic interaction between connections carried by the fornix and cholinergic input to the inferotemporal cortex for episodic memory.
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Croxson PL, Browning PGF, Gaffan D, Baxter MG (2008) Cholinergic depletion of the inferior temporal cortex interferes with recovery from episodic memory deficits. Neuroscience 2008 Abstracts 292.7/SS20. Society for Neuroscience, Washington, DC.
Summary: Cholinergic innervation of the temporal lobe has been suggested to have a role in episodic memory, a function which is also disrupted by lesions or disconnections of the medial temporal lobe circuit. Acetylcholine may be necessary for the specific function of some brain regions. Alternatively, it may be necessary for cortical plasticity and remodeling in those conditions in which the animal has to adapt following new task demands or injury. To investigate the role of cholinergic projections to inferotemporal cortex in episodic memory, and how loss of these projections might interact with damage to other brain structures necessary for normal memory function, we trained monkeys preoperatively on object-in-place scene discrimination problems until they could rapidly learn many problems within a testing session. Because learning occurs rapidly, mostly in a single trial, and depends on the presentation of discrimination problems in unique background scenes, this task models key features of human episodic memory. For the first stage of the experiment, the monkeys then received either a fornix transection or mammillary body ablation, both of which are known to impair learning in this task. All of the monkeys were impaired at scene learning after fornix or mammillary body lesions compared to their preoperative performance, consistent with previous results. In the second stage of the experiment, the monkeys underwent a second surgery in which we used the immunotoxin ME20.4-saporin to selectively deplete cholinergic inputs to the inferotemporal cortex. We then re-tested the monkeys on scene learning, and they were no more impaired than they were after their first surgery. This result is in striking contrast to an earlier finding by our laboratory that the effect of fornix transection is greatly exacerbated by prior depletion of acetylcholine from inferotemporal cortex (Browning et al. 2008, in press). The key difference between these two experiments is the order in which the lesions were placed: cholinergic depletion of inferotemporal cortex before fornix transection results in severe amnesia, whereas severe amnesia does not occur if the lesions are sustained in the opposite order. This finding suggests that monkeys require acetylcholine in inferotemporal cortex in order to adjust to the effects of a fornix lesion on episodic memory. This is consistent with a role for cholinergic input to neocortex in cortical plasticity and remodelling, rather than a specific role in certain brain functions such as episodic memory.
Related Products: ME20.4-SAP (Cat. #IT-15)
Baxter MG, Kyriazis DA, Croxson PL (2008) Cholinergic depletion of prefrontal cortex impairs acquisition of the delayed response task in rhesus monkeys. Neuroscience 2008 Abstracts 292.9/SS22. Society for Neuroscience, Washington, DC.
Summary: The involvement of corticopetal cholinergic projections in cognition remains difficult to define. Some investigators have suggested that normal cortical function requires an intact cholinergic input, whereas others emphasize a selective role of acetylcholine in attentional function or plasticity. Because of the anatomical and functional homology of human and macaque cortical structures, studies of the effects of selective ablation of cholinergic projections to cortical regions in the macaque would clarify the functions for which these projections are essential. We have tested 3 male rhesus monkeys with multiple bilateral injections of the immunotoxin ME20.4-saporin into lateral and orbital prefrontal cortex on a suite of cognitive tasks dependent on the integrity of orbital and ventrolateral prefrontal cortex, on which they were unimpaired. These tasks included new object-in-place scene learning, strategy implementation, and reinforcer devaluation. To determine the involvement of acetylcholine in dorsolateral prefrontal cortex function, we then trained these monkeys on the spatial delayed response task (Goldman, 1970; Bachevalier and Mishkin, 1986) in a manual testing apparatus. In this task the monkey watches as an experimenter places a small food reward in one of two wells of a test tray and then covers both wells with identical gray plaques. After a brief delay (1-5 sec) during which an opaque screen is interposed between the monkey and experimenter, the monkey is allowed to obtain the reward by displacing the plaque covering the well that was baited by the experimenter. Thus, the monkey must maintain the baited location (left or right) in memory during the brief delay interval in order to choose correctly. Performance of this task is devastated by ablation of dorsolateral prefrontal cortex. The monkeys with cholinergic depletion of lateral and orbital prefrontal cortex were also unable to learn the task to criterion, which four unoperated control monkeys learned readily. This finding suggests that acetylcholine, although not critical for functions of ventrolateral and orbital prefrontal cortex, is essential for dorsolateral prefrontal cortex function. An alternative explanation, which we are currently investigating, is that acetylcholine is necessary for the prefrontal cortex to adapt to the different task demands of delayed response, relative to the tests of discrimination learning with which these monkeys had extensive experience. This would be consistent with a role for cholinergic input to neocortex in cortical plasticity and remodeling.
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Gaffan D, Baxter MG, Browning PGF (2007) Intact delayed nonmatching-to-sample in monkeys with combined lesions of the temporal cortical cholinergic system and the fornix. Neuroscience 2007 Abstracts 341.11. Society for Neuroscience, San Diego, CA.
Summary: Rhesus monkeys were pre-operatively trained in truly trial-unique delayed nonmatching-to-sample (DNMS) in an automated apparatus. They were then divided into a control group (n=3) and an experimental group (n=3) and received injections into the inferior temporal cortex of either saline (controls) or the selective cholinergic immunotoxin ME20.4-saporin (experimentals). A postoperative DNMS test showed no significant impairment in the experimental group, both groups performing at their pre-operative level. Both groups then underwent a second surgery to transect the fornix. Again, there was no significant impairment in DNMS, both groups performing at their pre-operative level. If the lesions are confirmed histologically then these results are in marked contrast to our findings with scene learning, in which monkeys with the same combined lesion as those in the present experimental group were severely impaired. However, a number of recent studies have shown that tasks with temporally complex events extended over trials, like DNMS, discrimination learning set, and serial reversal set, depend on a short-term prospective memory strategy that is supported by the interaction of temporal cortex with prefrontal cortex. Thus, the performance of DNMS does not require the laying down of new long-term memories.
Related Products: ME20.4-SAP (Cat. #IT-15)
Browning PG, Gaffan D, Baxter MG (2007) Severe visual learning impairments in monkeys with combined but not separate lesions of the temporal cortical cholinergic system and the fornix. Neuroscience 2007 Abstracts 341.7. Society for Neuroscience, San Diego, CA.
Summary: A dense amnesia can be produced in the monkey by sectioning the anterior temporal stem, amygdala and fornix, a procedure which deafferents temporal cortex from modulatory inputs from the midbrain and basal forebrain. The present experiment investigated the neurochemical specificity of these severe learning impairments by selectively destroying cholinergic projections to the entire inferior temporal cortex by making multiple injections of the immunotoxin ME20.4-saporin into the inferior temporal cortex bilaterally. Six male macaque monkeys were preoperatively trained to learn new object-in-place discrimination problems each day until they could rapidly learn many such problems within a testing session. The monkeys then underwent surgery and received either injections of immunotoxin (n=3) or injections of saline (n=3). Both groups of monkeys were unimpaired when postoperative and preoperative performance were compared. Each monkey then underwent a second surgery to transect the fornix. After this surgery monkeys who had previously received injections of immunotoxin into temporal cortex showed a severe learning impairment, whereas monkeys who had previously received injections of saline showed a mild impairment. Monkeys with the combined immunotoxin plus fornix lesion were also severely impaired at concurrent object discrimination learning. These results suggest that different neuromodulatory inputs to inferior temporal cortex may act in concert to support cortical plasticity in visual learning such that the loss of acetylcholine only is not sufficient to disrupt normal learning behavior. The results also suggest that in monkeys, as in humans with Alzheimer’s disease, severe memory impairments occur only when a loss of acetylcholine projections to cortex is accompanied by organic tissue damage.
Related Products: ME20.4-SAP (Cat. #IT-15)
Baxter MG, Kyriazis DA, Croxson PL (2007) Cholinergic depletion of prefrontal cortex does not impair episodic memory or strategy implementation in rhesus monkeys. Neuroscience 2007 Abstracts 341.9. Society for Neuroscience, San Diego, CA.
Summary: The prefrontal cortex is involved in regulating multiple aspects of memory, decision-making, and cognitive control. Cholinergic input to prefrontal cortex is thought to be involved in supporting its functions. To examine this hypothesis we tested 4 rhesus monkeys (3 male) with cholinergic depletion of ventrolateral prefrontal cortex (N=2) or the entire prefrontal cortex, excluding its medial aspect (N=2). Selective cholinergic depletion was produced by multiple injections of the immunotoxin ME20.4-saporin (0.02 ug/ul) into the prefrontal cortex. These monkeys were tested on two tasks that each require frontal-inferotemporal interaction, as well as an intact ventrolateral prefrontal cortex. The first, strategy implementation, requires monkeys to apply different choice strategies to different categories of objects in order to maximize the rate of reward delivery, and engages decision-making and cognitive control. The second, scene memory, is a test of episodic memory in which monkeys rapidly learn 20 new object-in-place scene discrimination problems within a single test session. Cholinergic depletions of prefrontal cortex, whether they were limited to ventrolateral prefrontal cortex or included the whole of lateral and orbital prefrontal cortex, were without effect on either strategy implementation or new scene learning relative to each monkey's preoperative performance. Thus, episodic memory and strategy implementation can proceed normally even with severely disrupted cholinergic input, so loss of cholinergic input on its own cannot explain impaired prefrontal function in conditions such as Alzheimer's disease. Acetylcholine may work in tandem with other neuromodulators to affect prefrontal cortex function; alternatively, it may only be involved in very specific aspects of cortical function, for example representational plasticity.
Related Products: ME20.4-SAP (Cat. #IT-15)
Schechter LE, Smith DL, Rosenzweig-Lipson S, Sukoff SJ, Dawson LA, Marquis K, Jones D, Piesla M, Andree T, Nawoschik S, Harder JA, Womack MD, Buccafusco J, Terry AV, Hoebel B, Rada P, Kelly M, Abou-Gharbia M, Barrett JE, Childers W (2005) Lecozotan (SRA-333): a selective serotonin 1A receptor antagonist that enhances the stimulated release of glutamate and acetylcholine in the hippocampus and possesses cognitive-enhancing properties. J Pharmacol Exp Ther 314(3):1274-1289. doi: 10.1124/jpet.105.086363
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Kamke MR, Brown M, Irvine DR (2005) Origin and immunolesioning of cholinergic basal forebrain innervation of cat primary auditory cortex. Hear Res 206(1-2):89-106. doi: 10.1016/j.heares.2004.12.014
Summary: In this study the authors assessed the use of a cholinergic immunotoxin while examining cholinergic basal forebrain input to the primary auditory cortex in cat. Six 0.5 µg injections of ME20.4-SAP (Cat. #IT-15) were made into the putamen/globus pallidus, and cholinergic cell survival was examined by immunohistochemistry. The injected area showed a large reduction in number of AChE-positive fibers in the primary auditory cortex. This provides the evidence of the efficacy of ME20.4-SAP for investigating plasticity in cat auditory cortex.
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Molecular neurosurgery with targeted toxins
Wiley RG, Lappi DA (2005) Molecular neurosurgery with targeted toxins. Humana Press, Totowa, New Jersey.
Summary: The idea behind the book was to provide a road map for the users of Molecular Neurosurgery to see how experienced scientists used these exceptional reagents in their work. Experiments with several targeted toxins are described, and readers can get an idea either specifically about a targeted toxin that they’re using, or about how a type of molecule is used and at what dosage, in a paradigm similar to theirs.
Related Products: 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), SSP-SAP (Cat. #IT-11), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), IB4-SAP (Cat. #IT-10), CTB-SAP (Cat. #IT-14)
Ridley RM, Baker HF, Leow-Dyke A, Cummings RM (2005) Further analysis of the effects of immunotoxic lesions of the basal nucleus of Meynert reveals substantial impairment on visual discrimination learning in monkeys. Brain Res Bull 65(5):433-442. doi: 10.1016/j.brainresbull.2005.02.025
Summary: Several studies in marmoset monkeys indicate that cholinergic projections from the NBM to specific portions of the neocortex are necessary for visual discrimination learning. By combining analysis of studies using a total of 1.4 µg of ME20.4-SAP (Cat. #IT-15) into various areas of the brain, the authors show that degeneration of cholinergic projections contributes to the loss of functions dependent on the neocortex.
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Dudkin KN, Chueva V, Makarov FN, Bich TG, Roer AE (2005) Impairments in working memory and decision-taking processes in monkeys in a model of Alzheimer's disease. Neurosci Behav Physiol 35(3):281-289.
Related Products: ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03)
Effects of cholinergic deafferentation of the rhinal cortex on visual recognition memory in monkeys.
Turchi J, Saunders RC, Mishkin M (2005) Effects of cholinergic deafferentation of the rhinal cortex on visual recognition memory in monkeys. Proc Natl Acad Sci U S A 102(6):2158-2161. doi: 10.1073/pnas.0409708102
Summary: The rhinal cortex has been shown to play a critical role in recognition memory. The investigators examined the effect of eliminating cholinergic input to the rhinal cortex on the formation of new visual memories in macaques. Animals were given 0.01 µg injections of ME20.4-SAP (Cat. #IT-15) into the perirhinal and entorhinal cortices. The selective cholinergic deafferentation produced a substantial impairment of visual recognition memory, suggesting that cholinergic activation is essential for the formation of new visual memories.
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Impairments of working memory processes on a model of Alzheimer’s disease in monkeys
Dudkin KN, Chueva IV, Makarov FN, Beach TG, Roher AE (2003) Impairments of working memory processes on a model of Alzheimer’s disease in monkeys. Neuroscience 2003 Abstracts 626.8. Society for Neuroscience, New Orleans, LA.
Summary: We have investigated the characteristics of visual working memory in a delayed-discrimination task in a model of Alzheimer’s disease (AD) in rhesus monkeys. Three animals received unilateral stereotaxic intracerebroventricular injection of the nucleus basalis of Meynert and three monkeys received sterile saline injections and thus served as controls. The lesioning agent consisted of a ribosomal toxin, saporin, conjugated to monoclonal antibodies against (the nbM lesion) the p75 neurotrophin receptor (p75NTR), which is expressed almost exclusively on cholinergic neurons of the nbM. The rationale for the model is the same as for a rabbit model of AD (Roher et al, Ann. NY Acad Sci. 2000). The monkeys were trained to discriminate stimuli with different types of visual information (spatial frequency gratings, color, spatial choice, spatial relationships between components of objects). The data obtained demonstrate that the nbM lesioning agent had a weak effect on visual differentiation without delay (long-term memory), but significantly decreased the duration of information storage (by a factor of 2 – 3) in working memory later two months after injection. These changes depended on temporal stage after injection and stimulus properties, and were accompanied by increase of motor reaction time and of refusal of task decision. In monkeys that were sham injected, there were no alterations in working memory characteristics. The results suggest that considerable worsening of the working memory characteristics for monkeys after lesion of the nbM reflects the formation of an AD model in these monkeys. The principles of functional organization of working memory and role of pathology of the cortical mechanisms in an impairment of memory characteristics are discussed.
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Dudkin KN, Chueva IV, Makarov FN (2003) [Interaction between sensory and cognitive processes in visual recognition: the role of the associative areas of the cerebral cortex] Russian. Ross Fiziol Zh Im I M Sechenova 89(10):1226-1239.
Summary: The authors used ME20.4-SAP(Cat. #IT-15).
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Featured Article: Subplate neurons and functional maturation of thalamocortical synapses
Kanold PO (2003) Featured Article: Subplate neurons and functional maturation of thalamocortical synapses. Targeting Trends 4(4)
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Read the featured article in Targeting Trends.
See Also:
Wiley RG, Lappi DA (2003) Targeted toxins in pain. Adv Drug Deliv Rev 55(8):1043-1054. doi: 10.1016/s0169-409x(03)00102-9
Summary: The authors discuss the use of 'molecular neurosurgery' in the study of nociception. Applications using targeted toxins, which include immunotoxins, protein-toxin conjugates, or peptide-toxin conjugates, are illustrated. The authors describe the use of these molecules as research tools, as well as their potential for therapeutics. A helpful table is included that lists neuronal surface markers and class of cells targeted for each targeted toxin. Reagents discussed: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-Saporin (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP (Cat. #IT-12), Orexin-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), and acetylated LDL-SAP (Cat. #IT-08).
Related Products: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Orexin-B-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), Acetylated LDL-SAP (Cat. #IT-08)
Role of subplate neurons in functional maturation of visual cortical columns.
Kanold PO, Kara P, Reid RC, Shatz CJ (2003) Role of subplate neurons in functional maturation of visual cortical columns. Science 301(5632):521-525. doi: 10.1126/science.1084152
Summary: Subplate neurons play a role in the development of connections between the thalamus and cerebral cortex. The authors used 0.5-µl injections of 0.25-1.0 mg/ml of ME20.4-SAP (Cat. #IT-15) to eliminate p75 receptor-positive neurons in the subplate of cats to investigate whether these neurons are involved in the organization and maturation of the visual cortex. This study also uses mouse IgG-saporin (Cat. #IT-18) as a control.
Related Products: ME20.4-SAP (Cat. #IT-15), Mouse IgG-SAP (Cat. #IT-18)
Beach TG, Potter PE, Sue LI, Fisher A, Scott S, Layne KJ, Newell AJ, Roher AE, Walker DG (2002) Cerebral abeta deposition induced by cortical cholinergic deafferentation is reduced by cholinergic therapy. Neuroscience 2002 Abstracts 722.9. Society for Neuroscience, Orlando, FL.
Summary: We have previously shown that cortical cholinergic deafferentation in rabbits results in cerebral Abeta deposition (Neurosci Lett 283:9-12, 2000). We have also shown that cholinergic therapy with acetylcholinesterase inhibitors and muscarinic agonists reduces Abeta concentrations in the CSF and cortex of normal rabbits (Neurosci Lett 310:21-24, 2001; Brain Res 905:220-223, 2001). Here we show that the histologic deposition and biochemical elevations of Abeta induced by cholinergic immunotoxin are reduced by systemic therapy with AF267B, an M1-selective muscarinic agonist, and physostigmine, an acetylcholinesterase inhibitor. Rabbits received i.c.v. injections of an immunotoxin composed of the p75 NTR-directed monoclonal antibody ME20.4 conjugated to saporin, a ribosomal toxin. One group of animals received s.c. AF267B (2 mg/kg/day) while another group received s.c. physostigmine (3 mg/kg/day). Control groups received either i.c.v. immunotoxin or sham lesion (i.c.v. saline) and no treatment. Four weeks after surgery, imunohistochemical staining for Abeta showed frequent positive blood vessels and perivascular diffuse plaques in the control group which received immunotoxin injection and no treatment. This was significantly reduced in animals which received either AF267B or physostigmine. Cerebrospinal fluid Abeta concentrations were also reduced significantly by both drug treatments. These results are directly relevant to humans since cortical cholinergic deafferentation is part of normal human aging.
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Developmental regulation of GABA Receptor subunits requires subplate neurons.
Kanold PO, Shatz CJ (2002) Developmental regulation of GABA Receptor subunits requires subplate neurons. Neuroscience 2002 Abstracts 530.11. Society for Neuroscience, Orlando, FL.
Summary: Subplate neurons (SP) are required for formation and patterning of thalamocortical connections. In visual cortex, SP ablation before the onset of the critical period, but when LGN axons are already in layer 4, prevents segregation into ocular dominance columns (ODCs) and emergence of functional orientation columns. Recent studies have linked ODC plasticity with maturation of inhibitory circuitry, which requires the appropriate expression and developmental regulation of GABA receptor subunits. We therefore wondered if SP ablation alters GABA-R subunit expression. Focal injections of kainic acid or immunotoxin were made into cat SP between P7-P10, just prior to the onset of ODC formation. 3 weeks later, in situ hybridization revealed that expression of several subunits of the GABA-A receptor was reduced in the ablated region, especially in layer 4. Other genes involved in synaptic function such as Homer and mGluR subunits also decreased in expression. These changes in gene expression suggest that the efficacy of inhibition in layer 4 is reduced. A reduction in postsynaptic GABA receptors is consistent with previously observed increases in BDNF and GAD expression after SP ablation. These observations imply that SP neurons are essential for the maturation of cortical inhibition, which in turn may be needed for the formation of ODCs and for the functional maturation of thalamocortical connections.
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Cholinergic neurons in the rabbit forebrain: Chemoarchitecture, in vivo labeling, immunolesions
Varga C, Grosche J, Brauer K, Seeger J, Harkany T, Hartig W (2002) Cholinergic neurons in the rabbit forebrain: Chemoarchitecture, in vivo labeling, immunolesions. Neuroscience 2002 Abstracts 35.3. Society for Neuroscience, Orlando, FL.
Summary: While the rabbit basal forebrain and its cholinergic components became useful targets for modeling of neuropathological changes associated with Alzheimer’s disease, their neuroanatomical organization is still largely elusive. Hence, we focused on (i) the number of cholinergic basal forebrain neurons (CBFN)in the major nuclei based on choline acetyltransferase (ChAT) immunoperoxidase labeling, (ii) the density of ChAT-immunoreactive fibers in distinct neocortical and hippocampal areas, (iii) mapping of projecting CBFN by low-affinity neurotrophin receptor p75 (p75NTR ) staining and (iv) the double fluorescence labeling of ChAT and the neuronal markers p75NTR, nitric oxide synthase (NOS), calbindin, calretinin, parvalbumin, tyrosine hydroxylase and substance P. While cholinergic interneurons were found in the hippocampus, they were not detectable in the neocortex. CBFN were shown to abundantly co-express p75NTR, except in the substantia innominata and ventral pallidum. Whereas cholinergic neurons were devoid of most investigated markers, a subset also contained calbindin or NOS. The selective in vivo labeling of CBFN was achieved with intracerebroventricularly (i.c.v.) injected carbocyanine 3-conjugated ME20.4IgG that recognizes an extracellular epitope of p75NTR. Parallel experiments revealed that the i.c.v. injection of ME20.4IgG-saporin conjugates led to the specific immunolesion of cholinergic cells in about one week, whereas long-term effects of the immunotoxin remain to be further elucidated.
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Effects of cholinergic deafferentation of rhinal cortex on visual recognition in monkeys
Turchi JN, Saunders RC, Mishkin M (2002) Effects of cholinergic deafferentation of rhinal cortex on visual recognition in monkeys. Neuroscience 2002 Abstracts 82.5. Society for Neuroscience, Orlando, FL.
Summary: Excitotoxic lesions of the rhinal (perirhinal/entorhinal) cortices yield substantial deficits in visual recognition (Baxter and Murray, 2001; Malkova et al., 2001). To evaluate the mnemonic role of cholinergic inputs to this region, we compared the visual recognition performance of untreated monkeys with that of monkeys given rhinal cortex infusions of the selective cholinergic immunotoxin ME20.4-SAP. This toxin binds to the p75 receptor, borne by corticopetal cholinergic neurons of the basal forebrain, and is retrogradely transported to the cell body where it permanently destroys ribosomal function. Both groups were first trained to criterion in the rule for delayed nonmatching-to-sample (DNMS) with trial-unique stimuli at a 10-s delay in a Wisconsin General Testing Apparatus. This was followed by treatment and recovery for the experimental group (n=3) and an equivalent rest period for the control group (n=4), after which both groups were retrained on the DNMS rule and then given a memory performance test with increasing delays (30, 60, and 120 s) and list lengths (3, 5, 10, and 20 stimuli). The experimental group relearned the DNMS rule without significant impairment but then demonstrated robust deficits when tested with increasing delays (a mean of 83% vs 95% for controls) and list lengths (67% vs 86% for controls). The findings complement results obtained in a study of muscarinic receptor blockade in the perirhinal cortex (Tang et al., 1997) and indicate that cholinergic integrity of the rhinal cortex is critical for visual recognition memory.
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Easton A, Ridley RM, Baker HF, Gaffan D (2002) Unilateral lesions of the cholinergic Basal forebrain and fornix in one hemisphere and inferior temporal cortex in the opposite hemisphere produce severe learning impairments in rhesus monkeys. Cereb Cortex 12(7):729-736. doi: 10.1093/cercor/12.7.729
Summary: The authors used a combination of basal forebrain lesioning using ME20.4-SAP (Cat. #IT-15) and surgery to isolate the inferior temporal cortex and medial temporal cortex from cholinergic afferents in rhesus monkeys. Testing of the treated animals demonstrated severe impairments in learning visual scenes and object-reward associations.
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Extensive immunolesions of basal forebrain cholinergic system impair offspring recognition in sheep.
Ferreira G, Meurisse M, Gervais R, Ravel N, Levy F (2001) Extensive immunolesions of basal forebrain cholinergic system impair offspring recognition in sheep. Neuroscience 106(1):103-116. doi: 10.1016/s0306-4522(01)00265-2
Summary: Through the use of 192-Saporin (Cat. #IT-01) the association of basal forebrain cholinergic neurons to learning instrumental tasks has been well established in the rat. The authors wished to examine whether these neurons were also associated with social learning tasks, such as offspring recognition in sheep. Using ME20.4-SAP (Cat. #IT-15) the basal forebrain cholinergic neurons of sheep were lesioned by intraventricular bilateral injections (150 µg). The results demonstrate that these neurons contribute to visual discrimination learning, and are involved in formation of lamb recognition memory.
Related Products: 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15)
Ferreira G, Meurisse M, Tillet Y, Lévy F (2001) Distribution and co-localization of choline acetyltransferase and p75 neurotrophin receptors in the sheep basal forebrain: implications for the use of a specific cholinergic immunotoxin. Neuroscience 104(2):419-439. doi: 10.1016/s0306-4522(01)00075-6
Summary: ME20.4 is a monoclonal antibody (Cat. #AB-N07) that has been shown to bind the p75 receptor in rabbit, sheep, dog, cat, raccoon, pig, and several primate species. Ferreira et al. investigate ME20.4-SAP (bilateral, 150 µl per ventricle, 50-150 µg total; Cat. #IT-15) use in sheep to assess distribution and localization of p75. The authors demonstrate 80-95% loss of basal forebrain cholinergic neurons and acetylcholinesterase-positive fibers in the hippocampus, olfactory bulb, and entorhinal cortex.
Related Products: ME20.4-SAP (Cat. #IT-15), NGFr (ME20.4, p75) Mouse Monoclonal (Cat. #AB-N07)
Easton A, Ridley RM, Baker HF, Gaffan D (2000) Crossed unilateral lesions of the cholinergic basal forebrain (by me20.4IgG-saporin) and fornix from inferior temporal cortex produce severe learning impairments in rhesus monkeys. Neuroscience 2000 Abstracts 205.8. Society for Neuroscience, New Orleans, LA.
Summary: Section of the anterior temporal stem, amygdala and fornix in monkeys results in a dense anterograde amnesia. We have proposed that this impairment is a result of isolating the medial temporal lobe and inferior temporal cortex from their basal forebrain afferents. Evidence suggests that the cholinergic cells of the basal forebrain are important for learning and memory. In the present experiment we have made an immunotoxic unilateral lesion (ME20.4IgG-saporin), specific for the cholinergic cells of the basal forebrain, in combination with unilateral fornix damage in the same hemisphere, and a lesion of the inferior temporal cortex in the opposite hemisphere to disconnect these cholinergic cells from the medial temporal lobe and inferior temporal cortex. These monkeys were severely impaired at scene learning and concurrent visual discrimination learning, both of which are sensitive to sections of the anterior temporal stem, amygdala and fornix. This deficit is strongly correlated with the degree of acetylcholine loss in the basal forebrain in the hemisphere with the immunotoxic lesion. This result strengthens the proposal that the cholinergic cells of the basal forebrain are essential for new learning, and that their interaction with the medial temporal lobe and inferior temporal cortex is required for normal learning in monkey and man.
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McGaughy J, Everitt BJ, Robbins TW, Sarter M (2000) The role of cortical cholinergic afferent projections in cognition: impact of new selective immunotoxins. Behav Brain Res 115:251-263. doi: 10.1016/s0166-4328(00)00262-x
Summary: Review and comparison of immunolesioning techniques.
Related Products: 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15)
Featured Article: CBF lesioning in rabbits
Beach T (2000) Featured Article: CBF lesioning in rabbits. Targeting Trends 1(1)
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Read the featured article in Targeting Trends.
See Also:
Barefoot HC, Baker HF, Ridley RM (2000) Synergistic effects of unilateral immunolesions of the cholinergic projections from the basal forebrain and contralateral ablations of the inferotemporal cortex and hippocampus in monkeys. Neuroscience 98(2):243-251. doi: 10.1016/s0306-4522(00)00131-7
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Cortical cholinergic denervation elicits vascular A beta deposition.
Roher AE, Kuo YM, Potter PE, Emmerling MR, Durham RA, Walker DG, Sue LI, Honer WG, Beach TG (2000) Cortical cholinergic denervation elicits vascular A beta deposition. Ann NY Acad Sci 903:366-373. doi: 10.1111/j.1749-6632.2000.tb06388.x
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Cholinergic deafferentation of the rabbit cortex: a new animal model of Abeta deposition.
Beach TG, Potter PE, Kuo YM, Emmerling MR, Durham RA, Webster SD, Walker DG, Sue LI, Scott S, Layne KJ, Roher AE (2000) Cholinergic deafferentation of the rabbit cortex: a new animal model of Abeta deposition. Neurosci Lett 283:9-12. doi: 10.1016/s0304-3940(00)00916-2
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Ridley RM, Pugh P, Maclean CJ, Baker HF (1999) Severe learning impairment caused by combined immunotoxic lesion of the cholinergic projections to the cortex and hippocampus in monkeys. Brain Res 836:120-138. doi: 10.1016/s0006-8993(99)01641-8
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Ridley RM, Barefoot HC, MacLean CJ, Pugh P, Baker HF (1999) Different effects on learning ability after injection of the cholinergic immunotoxin ME20.4 IgG-saporin into the diagonal band of Broca, basal nucleus of Meynert, or both in monkeys. Behav Neurosci 113:303-315. doi: 10.1037//0735-7044.113.2.303
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Mrzljak L, Levey AI, Belcher S, Goldman-Rakic PS (1998) Localization of the m2 muscarinic acetylcholine receptor protein and mRNA in cortical neurons of the normal cholinergically deafferented rhesus monkey. J Comp Neurol 390:112-132. doi: 10.1002/(SICI)1096-9861(19980105)390:1<112::AID-CNE10>3.0.CO;2-Z
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Fine A, Hoyle C, MacLean CJ, Levatte TL, Baker HF, Ridley RM (1997) Learning impairments following injection of a selective cholinergic immunotoxin, ME20.4 IgG-saporin, into the basal nucleus of Meynert in monkeys. Neuroscience 81:331-343. doi: 10.1016/s0306-4522(97)00208-x
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