Chronic lisuride hydrogen maleate administration enhances muscarinic receptor binding in senescent rat brain

Changes in the regional density of muscarinic-1 (M1) receptors and the effect of lisuride hydrogen maleate on these changes were studied in senescent rat brain by in vitro autoradiography. In young adult controls, M1 receptor binding was most dense in the striatum and hippocampus, followed by the cerebral cortex and amygdala. Binding to M1 receptors was markedly lower in these areas of the senescent brain compared with the young adult brain. These decreases were reversed by intraperitoneal administration of 50 micrograms/kg.day lisuride for 14 days. The present results indicate that the therapeutic efficacy of lisuride depends on normalization of not only monoamine systems but also acetylcholine systems.