Pokala VN, Witt-Enderby PA, Johnson DA (2003) Effect of selective cholinergic lesion of the septohippocampal pathway on the carbachol stimulated GTPγS binding in rat hippocampus. Neuroscience 2003 Abstracts 799.7. Society for Neuroscience, New Orleans, LA.
Summary: Previously we have shown that selective lesion of the septohippocampal cholinergic pathway in the rat resulted in a significant decrease in hippocampal extracellular acetylcholine concentration and an increase in muscarinic receptor binding. The intent of this study was to investigate the effect of selective cholinergic lesion of the septohippocampal pathway on muscarinic receptor-coupled G protein activation. Measurement of agonist-stimulated GTP〔γ-35S〕 binding was used as a function of ligand-receptor interactions. Sprague-Dawley rats were infused into the medial septum with either the selective cholinergic immunotoxin 192 IgG-saporin (SAP) (0.22 μg in 1μl aCSF) or vehicle. After 6 weeks the rats were euthanized and the hippocampus dissected from the brain and quickly frozen. Hippocampal homogenate was analyzed for GTPγS binding following exposure to the muscarinic agonist carbachol (1 nM-10 mM). Data were analyzed to obtain EC50 of carbachol and Emax values for GTPγS binding using non-linear regression analysis. The results demonstrated, in control animals carbachol stimulated 35S GTPγS binding to be 150% over basal with an EC50 value of approximately 100 μM. However, in SAP lesioned animals no concentration dependent increase in 35S GTPγS binding occurred. Therefore, though we saw an increase in the muscarinic receptor binding at the hippocampus on SAP lesioning, these receptors seem to be nonfunctional.
Related Products: 192-IgG-SAP (Cat. #IT-01)