targeted-toxins

Q: I am interested in your product GAT1-SAP (Cat. #IT-32). Before ordering, I would like to know how long it takes until the toxin produces a lesion; Is seven days enough?

A: The usual time-course for saporin toxins is that behavioral effects start appearing at four days and usually plateau at seven days. However, keep in mind that it takes some time for dead cells to be cleared out, so histology on the animal should wait until at least two weeks after administration.

Related: Targeted Toxins

Goehler LE, Gaykema RPA (2011) Featured Article: Targeted lesion of caudal brainstem catecholamine neurons reveals their role in symptoms of fatigue. Targeting Trends 12(1)

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Read the featured article in Targeting Trends.

Zhang L, Hadley GA (2010) Application of anti-CD103 immunotoxin for saving islet allograft in context of transplantation. Chin Med J (Engl) 123(24):3644-51.

Summary: This work investigates whether depletion of CD103-positive cells protects transplanted islets from host-immune cell attack. Diabetes was induced in mice, followed by an islet transplant. Anti-CD103-SAP (Cat. #IT-50) was administered via i.p. injection (1.0 mg/kg or 2.0 mg/kg). Rat IgG-SAP (Cat. #IT-17) was used as a control. Diabetic mice treated with anti-CD103-SAP after islet transplantation had an indefinite survival time as compared to untreated mice that survived fewer than 20 days.

Related Products: Anti-CD103-SAP (Cat. #IT-50), Rat IgG-SAP (Cat. #IT-17)

Cerminara NL (2010) Cerebellar modules: individual or composite entities?. J Neurosci 30(48):16065-16067. doi: 10.1523/JNEUROSCI.4823-10.2010

Summary: This short review discusses the compartmentalization of cerebellar modules. Much research has been done to associate particular motor control functions with particular modules. Chemical lesioning is an inadequate technique because the lesion is non-specific. The use of CTB-SAP (Cat. #IT-14) to affect the function of a single module is discussed.

Related Products: CTB-SAP (Cat. #IT-14)

Joseph EK, Levine JD (2010) Mu and delta opioid receptors on nociceptors attenuate mechanical hyperalgesia in rat. Neuroscience 171(1):344-350. doi: 10.1016/j.neuroscience.2010.08.035

Summary: In this work the authors analyzed nociceptor populations mediating mechanical hyperalgesia in the rat. Rats received 3.2 µg of IB4-SAP (Cat. #IT-10) into the subarachnoid space between the L4 and L5 vertebrae. Hyperalgesia due to the administration of NGF was inhibited by DAMGO and SNC even in lesioned animals. These data indicate that most nociceptor populations are involved in mechanical hyperalgesia, and that the mu opioid and delta opioid receptors are co-expressed on some TrkA-positive nociceptors.

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

Koppen JR, Winter SS, Cheatwood JL, Wallace DG (2010) Role of the septohippocampal GABAergic system in spatial orientation. Neuroscience 2010 Abstracts 806.16/KKK21. Society for Neuroscience, San Diego, CA.

Summary: Spatial orientation depends on the integrity of multiple neural systems. For example, during the progression of Alzheimer’s Disease, degeneration of the basal forebrain is associated with cognitive impairments including episodes of wandering. The medial septum projects both cholinergic and GABAergic fibers into the hippocampus. Research and therapies have typically focused on enhancing function of the cholinergic component; however, the GABAergic component has also been shown to contribute to hippocampal function. Previous attempts to characterize the role of the GABAergic system in spatial orientation involved non-selective lesion techniques in combination with the water maze task have failed to characterize the nature of the deficit mediating the impaired performance. Development of GAT1-Saporin immunotoxin provides a novel tool to selectively destroy GABAergic neurons in the medial septum. The current study examined the effects of injecting GAT1-Saporin or saline (sham lesion) into the medial septum on spatial orientation using the food-hoarding paradigm. The food-hoarding paradigm involves training rats to search for food pellets on a large circular table and carrying the food pellet directly to a visible refuge. Three probes dissociate the use of environmental and self-movement cues: 1) Hidden probe involved placing the refuge below the surface of the table, limiting rats to use distal environmental or self-movement cues to locate the refuge; 2) Dark Probe involved using the hidden refuge with the room lights off, limiting rats to use self-movement cues to locate the refuge; 3) New probe involved placing the hidden refuge on the opposite side of table, placing environmental and self-movement cues in conflict. Both sham and GAT1-Saporin rats were accurate in returning to the refuge during the Hidden probe. Only sham rats were accurate in carrying food to the refuge during the Dark probe. During the New probe, both groups initially carried the food pellet to the former refuge location. Although sham rats consistently carried the food pellet to the new refuge location after their initial error, GAT1-Saporin rats continued to perseverate to the former refuge location. The current study demonstrates a role for the septohippocampal GABAergic system in spatial orientation related to processing self-movement cues.

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

Rossi CA, Lehmkhule MJ, Kesner RP, Dudek FE (2010) Evidence that focal hippocampal interneuron loss disrupts theta-rhythm activity in dorsal CA1. Neuroscience 2010 Abstracts 811.1/LLL64. Society for Neuroscience, San Diego, CA.

Summary: Hippocampal theta activity (6-12 Hz) is an oscillatory local field potential that is thought to play a critical role in the encoding and storage of new information. As a hypothetical mechanism for theta rhythm generation, interneurons have been proposed to appropriately time the GABAergic inhibition of principal cells, as a means of organizing the theta pattern; however, little experimental work has been done to test this hypothesis directly. The current study aims to test in a relatively direct manner the hypothesis that interneurons synchronize the activity of pyramidal cells into theta-band oscillations. In the current study, SSP-saporin (a selective interneuron-targeting neurotoxic lesioning agent) was infused into six sites located in dorsal CA1 in order to create an interneuron-only lesion confined to that area. Animals were also implanted with chronic field potential recording electrodes aimed at areas CA1, CA3, and dentate gyrus. All animals were then monitored, using video and EEG recordings, 24 h per day for the next 7 to 10 days. In addition, EEG was recorded while animals were allowed to explore a novel open field for 30 min in order to create a situation where theta rhythm activity is highly likely to occur. Local field potentials from animals that received SSP-Saporin injections into the dorsal CA1 area revealed attenuation of theta rhythm activity in the lesioned area. Recordings from controls, however, showed a robust peak of activity in the theta frequency band, similar to what has been traditionally described in the hippocampus of naive rats. Together, these results suggest that local elimination of interneurons disrupts local theta rhythm without induction of seizure activity. These experiments provide evidence concerning the possible organizational role of GABAergic interneurons in theta rhythm, an important component of normal hippocampal function.

Related Products: SSP-SAP (Cat. #IT-11)

Gielow M, Roland J, Servatius, RJ Pang KCH (2010) Do GAT1-saporin lesions of the medial septum damage GABAergic afferents to the medial septum?. Neuroscience 2010 Abstracts 811.3/LLL66. Society for Neuroscience, San Diego, CA.

Summary: 192-IgG saporin is an antibody directed to the p75 receptor conjugated to the ribosomal-inactivating compound saporin. 192-IgG saporin has been widely used to selectively ablate cholinergic cells of the basal forebrain. Cholinergic lesions are typically made by injections of 192-IgG saporin at the soma in basal forebrain nuclei. However, 192-IgG saporin is also effective in damaging specific cholinergic projections by administration of the toxin in the axon terminal region. Recently, GAT1-saporin has been developed as a tool to selectively damage cells expressing the GABA transporter GAT1. GAT1-saporin combines an antibody to the GABA transporter GAT1 with saporin. GAT1 transporters are primarily localized to neurons and GAT1-saporin has been shown to selectively damage GABAergic neurons in the BNST and medial septum. Given the similarity to 192-IgG saporin, a major question is whether GAT1-saporin is effective in damaging GABAergic afferents to the area of administration. Our previous studies found that GAT1-saporin administered to the medial septum / diagonal band of Broca (MSDB) damages GABAergic septohippocampal neurons and impaired performance on delayed match to position tasks. While it seems likely that damage of GABAergic MSDB neurons is responsible for these behavioral impairments, one cannot rule out the possibility that destruction of GABAergic afferents to the MSDB may also contribute. Therefore, the present study was undertaken to determine whether GAT1-saporin lesions of the MSDB damage the GABAergic hippocamposeptal projection. Male Sprague Dawley rats received both fluorogold and either GAT1-saporin or vehicle in medial septum. Immunocytochemistry for choline acetyltransferase and parvalbumin confirmed the extent of the lesion. The majority of hippocamposeptal GABAergic neurons contain the neuropeptide somatostatin. Quantification of double-labeled hippocampal fluorogold-positive cell bodies with anti-somatostatin immunofluorescence was performed using unbiased stereology. Preliminary data suggest that GABAergic hippocamposeptal neurons are intact. These results will be important in understanding the damage produced by GAT1-saporin.

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

Matchynski JJ, Lowrance SA, Rossignol J, Dekorver NW, Puckett ND, Pappas CA, Trainor KJ, Delongchamp JL, Radwan J, Heldt JC, Dey ND, Dunbar GL (2010) The effects of a combination of antioxidants and essential fatty acids as treatment for Alzheimer’s disease in the mu-p75 saporin-injected model. Neuroscience 2010 Abstracts 856.15/I21. Society for Neuroscience, San Diego, CA.

Summary: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is marked by a progressive loss of memory and affects over five million people nationwide (Alzheimer’s Association, 2010). It is characterized by an increase in oxidative stress, amyloid plaques, neurofibrillary tangles, and the loss of cholinergic neurons. Mice injected with the ribosome deactivating protein, mu-p75 saporin, model the deficits in memory, loss of cholinergic neurons, and increased oxidative stress observed in AD. The current study aimed to decrease the deficits observed in the saporin mouse model using a combination of antioxidants from tart cherries and essential fatty acids, Cerise© total body rhythm (TBR). Mice dosed with TBR or methylcellulose were given bilateral ventricular injections of phosphate buffer saline or saporin. Memory and motor functioning were then measured in a series of behavioural tests. Results indicate that TBR decreased the memory deficits observed in object recognition, place recognition, and Morris-water-maze tasks, as well as the inflammatory response and loss of cholinergic neurons in the medial septum. The findings suggest that TBR could provide an effective, adjunctive treatment that may delay the onset or decrease the severity of AD.

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

Hernandez MA, Hernández-Melesio M, Gonzalez-Ezquivel D, Quevedo-Corona L, Jiménez-Cataño M, Santoyo-Pérez M, Rios-Castañeda C, Pérez-Severiano F (2010) Molsidomine promotes the recovery of cognitive deficit induced by 192 IgG saporin in rats. Neuroscience 2010 Abstracts 856.27/I33. Society for Neuroscience, San Diego, CA.

Summary: The NO donor molsidomine (MOLS) has been used as a pharmacological tool in order to antagonize the cognitive deficit associated to cholinergic hypofunction produced by scopolamine. However, the participation of NO in the recovery of cholinergic deficit due to the administration of the cholinergic immunotoxin, 192 IgG saporin (SAP) has not been analyzed. The aim of the present study was to determine the effect of MOLS to counteract the cognitive deficits induced by cholinergic denervation in the object recognition task. Male Wistar rats were divided in the follow experimental groups according to the intraseptal administration of SAP and its vehicle PBS, and the injection (i.p) of the NO donor molsidomine and its vehicle saline: SAP (0.22 µg), PBS (0.1M pH 7.4), molsidomine (4mg/kg), SAP/molsidomine. The single dose of MOLS used in this study antagonized the cognitive failure related to SAP administration and increased the exploration time of novel object. We conclude that MOLS promote the acquisition of recognition memory in the model of cholinergic denervation associated to 192 IgG SAP and further immunohistological studies are being carried out in order to demonstrate that nitric oxide could have an effect over the cholinergic functionality.

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