Neuronal localization of benzodiazepine receptors in the murine cerebellum.

Selective genetic and chemical lesions which affect specific neuronal populations in the cerebellum were studied for changes in benzodiazepine receptors. Destruction of cerebellar climbing fibers with 3-acetylpyridine, did not affect cerebellar benzodiazepine receptors. Destruction of Purkinje, basket and stellate cells with intracerebellar kainic acid, caused moderate decreases in benzodiazepine receptor density. Destruction of Purkinje cells with chronic high doses of phenytoin also caused a significant decrease in benzodiazepine receptor density. In "weaver" mice, which have a severe loss of granule cells, benzodiazepine receptor density was unchanged, while the absolute number of benzodiazepine receptors decreased by 57%. In "staggerer" mice which have diminished Purkinje cells dendritic thickenings at their synapses with parallel fibers and subsequent granule cell loss, there was a 45% decrease in benzodiazepine receptor density and a 90% decrease in the absolute number of benzodiazepine receptors. These results suggest that benzodiazepine receptors exist on cerebellar Purkinje cells, that they probably also occur on cerebellar granule cells, and that they do not appear to be present on cerebellar glial cells or on climbing fibers.