[Chronic administration of bifemelane hydrochloride increases somatostatin receptor binding in aged rat brain]

Changes in the distribution and densities of somatostatin receptors (SS-R) in young adult and aged rat brain and the effects of chronic administration of bifemelane hydrochloride (bifemelane) on these changes were studied by in vitro quantitative autoradiography of iodinated [Tyr11] SS-14. SS-R was highest in density in the amygdala, followed by the cingulate cortex, temporal cortex, frontal cortex, hippocampus and septal nucleus in the young adult rats. In contrast, SS-R binding was markedly reduced in the frontal cortex, temporal cortex, cingulate cortex, hippocampus, amygdala and septal nucleus of aged rats compared to young adult rats. However chronic administration of bifemelane significantly increased SS-R binding in the frontal cortex, temporal cortex, cingulate cortex, hippocampus and septal nucleus of aged rats without effects on young adult rats. This bifemelane-induced increase in SS-R is considered to have important implications in the mechanism of the therapeutic efficacy of bifemelane.