targeted-toxins

Pang KCH, Jiao X, Servatius RJ (2008) Featured Article: Role of medial septal GABAergic neurons in learning and extinction: Effects of the novel GABA immunotoxin GAT1-SAP. Targeting Trends 9(1)

Related Products: GAT1-SAP (Cat. #IT-32)

Read the featured article in Targeting Trends.

Blanco-Centurion C, Gerashchenko D, Shiromani PJ (2007) Effects of saporin-induced lesions of three arousal populations on daily levels of sleep and wake. J Neurosci 27:14041-14048. doi: 10.1523/JNEUROSCI.3217-07.2007

Summary: Orexin neurons in the basal forebrain, tuberomammillary nucleus (TMN), and locus ceruleus (LC) are thought to regulate arousal. Rats were injected with two or three of the following targeted conjugates: anti-DBH-SAP (Cat. #IT-03), 0.25 µl bilateral injections of 1 µg/µl into the LC; orexin-SAP (Cat. #IT-20), 0.25 µl injection of 0.25 µg/µl into the TMN; 192-IgG-SAP (Cat. #IT-01), 3 µl injection of 2 µg/µl into the lateral ventricle. Small differences were observed in sleep architecture, but the data do not support the traditional hypothesis that these three areas of the brain are essential links in the control of wake levels.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20), 192-IgG-SAP (Cat. #IT-01)

Berdiev RK, Chepurnov SA, Veening JG, Chepurnova NE, van Luijtelaar G (2007) The role of the nucleus basalis of Meynert and reticular thalamic nucleus in pathogenesis of genetically determined absence epilepsy in rats: A lesion study. Brain Res 1185:266-274. doi: 10.1016/j.brainres.2007.09.010

Summary: Absence seizures due to epilepsy usually occur during passive behavior. This work investigated the role of the cholinergic nucleus basalis of Meynert (NB) and the reticular thalamic nucleus (RT) in these seizures. Rats received either 75 ng of 192-IgG-SAP (Cat. #IT-01) or the control, mouse IgG-SAP (Cat. #IT-18), into the NB and the RT. Loss of cholinergic neurons in the NB resulted in an increased number of spike-and-wave discharges, a marker for absence seizures.

Related Products: 192-IgG-SAP (Cat. #IT-01), Mouse IgG-SAP (Cat. #IT-18)

Shank EJ, Seitz PK, Bubar MJ, Stutz SJ, Cunningham KA (2007) Selective ablation of GABA neurons in the ventral tegmental area increases spontaneous locomotor activity. Behav Neurosci 121:1224-1233. doi: 10.1037/0735-7044.121.6.1224

Summary: To further examine the importance of the ventral tegmental area (VTA) g-aminobutyric acid (GABA) neurons in behavioral function, the authors lesioned the VTA of rats with dermorphin-saporin (Cat. #IT-12). Lesioned animals received 1 or 2 pmol/200 nl bilateral injections of conjugate; blank-SAP (Cat. #IT-21) was used as a control. Rats treated with dermorphin-SAP displayed significantly elevated motility as compared to control animals. Rats receiving 1 pmol of dermorphin-SAP returned to normal motility 14 days after treatment, but rats receiving 2 pmol maintained the increased motility through day 14.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Blank-SAP (Cat. #IT-21)

Frederick-Duus D, Guyton MF, Fadel J (2007) Food-elicited increases in cortical acetylcholine release require orexin transmission. Neuroscience 149:499-507. doi: 10.1016/j.neuroscience.2007.07.061

Summary: In these experiments the authors examine the hypothesis that orexin fibers from the hypothalamus are necessary for basal forebrain cholinergic system (BFCS) activation in a food restriction model. Rats received 200 ng of orexin-SAP (Cat. #IT-20) into the lateral hypothalamus/perifornical area. Lesioned animals that were also deprived of food displayed increased feeding latency when presented with food. These and other data indicate orexin in the BFCS is involved in attention to stimuli associated with homeostatic challenges.

Related Products: Orexin-B-SAP (Cat. #IT-20)

Millan-Aldaco D, Arias-Carrion O, Palomero-Rivero M, Drucker-Colin R, Murillo-Rodriguez E (2007) Transplant of hypocretin neurons into the lateral hypothalamus of a narcolepsy rat model. Neuroscience 2007 Abstracts 779.2/E4. Society for Neuroscience, San Diego, CA.

Summary: Narcolepsy, a disabling neurological disorder, is characterized by excessive daytime sleepiness, sleeps attacks, sleep fragmentation, and cataplexy. This sleep disorder has been linked to a loss of neurons into the lateral hypothalamus (LH) containing the neuropeptide hypocretin (HCRT). Our group has developed an experimental model in rats that mimics several aberrant behaviours observed in human narcolepsy. The bilateral administration of the neurotoxin hypocretin-2-saporin (HCRT2-SAP) into the LH of rats destroys most of the HCRT neurons (~90%) leading to develop narcolepsy as evaluated using EEG/EMG means. In order to replace the HCRT lost neurons by the local injection of the HCRT2-SAP, a suspension of cells from the hypothalamus obtained from rat pups (3-5 days old) were processed for grafting and stained with GFP. This cell suspension was injected into the LH of lesioned rats and they were sacrificed 21 days post-transplant. The brain was cut and sections containing LH were processed for HCRT immunohistochemistry as well as for the presence of HCRT-immunoflorescence neurons. We were able to differentiate the HCRT transplanted neurons into the LH of lesioned rats. Importantly, they were present at the target area 21 days after implant. These somata were similar in size and appearance to adult rat HCRT-immunoreactive neurons. Our results are very promising since the present study indicates that HCRT neurons obtained from rat pups can be grafted into a host brain and graft survived during 21 days. This experimental approach definitely addresses the possibility to replace HCRT neurons in narcolepsy in order to reverse this disease.

Related Products: Orexin-B-SAP (Cat. #IT-20)

Cusulin C, Aztiria E, Cacci E, Battaglini PP, Kokaia Z, Leanza G (2007) Survival, integration and differentiation of human neural stem cells transplanted into an animal model of cholinergic degeneration. Neuroscience 2007 Abstracts 779.5/E7. Society for Neuroscience, San Diego, CA.

Summary: The recently characterized F7B cell line, derived from human fetal cortex (Cacci et al, 2007) has been observed able to differentiate in vitro into different glial and neuronal subtypes. However, no much data is available about its capacity for differentiation in vivo. In the present work, F7B cells were grafted to the medial septum of newborn (P8) intact rats and to littermates that had been subjected to selective cholinergic deafferentation at P4 using the 192 IgG-saporin immunotoxin. The animals were sacrificed 1 or 3 months after grafting and the dissected brains were processed for immunocytochemistry, using cell-specific (HuNu and GFP) and differentiation markers (Dcx, GFAP, NeuN, and HuD). Overall, grafted F7B cells exhibited an excellent ability to survive and differentiate into the host tissue environment. Survival rate varied among the groups, being consistently higher when the cells were grafted into lesioned, as opposed to intact, animal. Moreover, a better survival was seen at 1 month, compared to 3 months post-grafting, regardless the lesion condition. Interestingly, the presence of a cholinergic depletion in the recipient appeared to affect differentiation of grafted F7B cells. In fact, higher numbers of Dcx+ and HuD+ cells were scattered within the grafts placed in lesioned animals, as compared to controls. In lesioned, but not intact animals, at 3 months post-grafting, sparse F7B cells were found to express the mature neuronal marker NeuN. On the other hand, grafted F7B immunoreactive for GFAP were similarly detected in all transplanted animals. F7B cells appear to be feasible for transplantation, being able to survive and differentiate into a developing brain, and to positively respond to the new environment created by a lesion. Further studies are warranted to test their actual capacity for functional integration.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Camp MC, Alcantara AA (2007) Cholinergic saporin lesions in the nucleus accumbens attenuate alcohol drinking. Neuroscience 2007 Abstracts 809.4/X26. Society for Neuroscience, San Diego, CA.

Summary: Identifying specific cell types and the plasticity that occurs within those neuronal networks that lead to alcohol drinking is critical for the development of improved treatment programs for alcoholism. We have previously reported that cholinergic neurons of the nucleus accumbens (NAc) undergo alcohol-induced intracellular and receptor neuroadaptations. These changes may facilitate acetylcholine (ACh) release, which in turn modulate the neuronal circuits that underlie alcohol drinking. We postulate that alcohol-induced neuroplasticity of the cholinergic system facilitates alcohol drinking whereas removal of ACh influences attenuates alcohol drinking. Cholinergic cell lesion studies investigating a direct causal role of these neurons in drug abuse and memory have reported their importance in reinforcement, conditioned place preference, reward-related procedural learning and working memory. The effects of accumbal cholinergic lesions on alcohol drinking, however, have not been examined. To test a direct causal link between cholinergic cells and alcohol drinking, the present study employed bilateral cholinergic cell lesions in the NAc and measured alcohol drinking in C57BL/6J mice. The effects of cholinergic ablation on alcohol drinking were examined following a Drinking in the Dark model of binge drinking and on motor impairment using the fixed speed rotarod test. Cholinergic ablations were produced by microinjections of mu p75-saporin into the NAc. After recovery, animals were given 20% (v/v) ethanol in water for 4 hours a day in the home cage starting 3 hours after lights off for 1 month. Cholinergic cell eliminated mice showed a 26% decrease in alcohol drinking compared to saline microinjected controls (p<0.05) and fell from the rotarod 24% sooner than controls (p<0.05). The present study provides evidence of a direct causal link between cholinergic cells and alcohol drinking. These results suggest that increased ACh release facilitates binge drinking, whereas removal of ACh signaling attenuates drinking. These findings provide the basis for accumbal cholinergic-targeted pharmaceutical and behavioral treatment programs designed to attenuate alcohol binge drinking.

Related Products: mu p75-SAP (Cat. #IT-16)

Saeed AW, Ribeiro-Da-Silva A (2007) Changes in neurokinin-1 receptor expression in populations of spinal lamina I neurons in rats lacking non-peptidergic nociceptive fibers. Neuroscience 2007 Abstracts 821.4/FF19. Society for Neuroscience, San Diego, CA.

Summary: Neurokinin-1 receptor (NK-1r)-containing lamina I projection neurons are deeply involved in the transmission of pain-related information to the brain. Previous studies have shown that lamina I neurons can be classified morphologically into fusiform, pyramidal and multipolar cells, and that these types differ in functional properties, with the pyramidal type being non-nociceptive. Our laboratory has shown not only a considerable increase in immunoreactivity for the NK-1r in animals with CFA-induced arthritis but also a de novo expression of these receptors by pyramidal neurons (Almarestani et al., Soc.Neurosci.Abstr., Program # 249.11, 2006). Based on this, we deemed it interesting to study whether pyramidal neurons would also express NK-1r in an animal model in which we have previously shown a drastic increase in NK-1r expression but no augmented nociceptive responses. To achieve this, we injected, under anesthesia, saporin (SAP) conjugated to the lectin IB4 into the left sciatic nerve of male Sprague Dawley rats to selectively lesion the non-peptidergic nociceptive C-fibers. Animals were sacrificed from 2 weeks to 2 months post-lesion. Horizontal sections of spinal segments L5 and L6 were cut and processed for IB4 binding and NK-1r immunoreactivity using immunofluorescence. Examination of IB4-SAP treated rats at several time points post-lesion revealed increased expression of NK-1r by lamina I cells of the fusiform and multipolar types on the side ipsilateral to the lesion, compared to the contralateral side and to controls. However, pyramidal cells seldom expressed the NK-1r in both control and lesioned animals. Surprisingly, we also observed a direct innervation of lamina I neurons by IB4-positive neurons in control animals, which did not occur ipsilaterally in lesioned animals. These observations support the concept that increased activity by the peptidergic nociceptive afferents may be important in the maintenance of nociceptive responses in the absence of non-peptidergic fibers.

Related Products: IB4-SAP (Cat. #IT-10)

Kline IV RH, Lemons LL, Wiley RG (2007) Antinociceptive effects of lumbar intrathecal neuropeptide y-saporin. Neuroscience 2007 Abstracts 821.5/FF20. Society for Neuroscience, San Diego, CA.

Summary: Spinal intrathecal (i.t.) neuropeptide Y (NPY) has been shown to be antinociceptive in the rat. Using lumbar i.t. NPY, coupled to the ribosomal inactivating protein, saporin, to selectively destroy spinal dorsal horn cells that express NPY receptors, we sought to determine the effect of this lesion on nocifensive behaviors in the hotplate and formalin tests and on NPY1R staining in the lumbar dorsal horn. Twenty Sprague Dawley male rats were injected i.t. with either saline or 500ng NPY-sap and then were tested on the hotplate for 30 days. Fifteen Long Evans female rats were injected i.t. with either saline or NPY-sap (500ng or 750ng) and then tested on the hotplate for two weeks followed by hindpaw formalin injection. In order to assess responses mediated by C or A-delta thermal nociceptors, hotplate testing used three temperatures: 44C (600 sec trial duration), 47C (200 sec trials), and 52C (first response or 30 sec). In male rats, lumbar i.t. NPY-sap increased hindpaw withdrawal latencies to 44, 47 and 52C, with the greatest effect on 44C. NPY-sap also reduced the total amount of hindpaw lick/guard responding (duration and number of responses) on the 44 and 47C hotplates. Female rats injected with 750ng of NPY-sap showed a decrease in the number of hindpaw lick/guard events on the 44C hotplate. Female rats also showed a decrease in the total number of hindpaw lick/guard events during the interphase (7-21min) and phase II (22-90min) of the formalin test. Additionally operant thermal place preference testing (45C vs 12C) was compared to hotplate reflex testing. Selectivity of NPY-sap was assessed by immunocytochemistry for cells expressing NPY1R and non-selectivity was assessed by staining for NK-1R. Based on the above findings we conclude that selective destruction of dorsal horn NPY1R-expressing neurons produces decreased thermal nociception to a range of noxious heat and also decreases responses to persistent noxious chemical stimulation during the formalin test. In summary, reduced nocifensive behaviors after NPY-sap were more prominent when assessing responses elicited by input from predominately C fiber activation (44C and formalin). This study was supported by the Department of Veterans Affairs.

Related Products: NPY-SAP (Cat. #IT-28)