GABA benzodiazepine and histamine-H1 receptors in the guinea pig cerebellum: effects of kainic acid injections studied by autoradiographic methods.

By using kainic acid (KA) to perform chemical lesions in the guinea pig cerebellum, we have caused degeneration of Purkinje cells without affecting cell morphology. Near the injection site we found a large decrease in autoradiographically labeled histamine-H1 and benzodiazepine receptors of the molecular layer while those receptors distant from the injection site were unaffected. GABA receptors in the granule cell layer remained uniformly constant even immediately adjacent to the lesion site. This evidence suggests that histamine-H1 and benzodiazepine receptors are present on neuronal elements (possibly on Purkinje cell dendrites) in the molecular layer of the cerebellum and that GABA receptors area associated with the KA-resistant granule cells.