Effects of bifemelane hydrochloride, a brain function improver, on muscarinic receptors in the CNS of senescence-accelerated mouse.

Senescence-accelerated mouse (SAM-P/8) is known as a murine model of aging and memory dysfunction, compared with control mouse (SAM-R/1). In the hippocampus of 9-month-old SAM-P/8, the Bmax of [3H]QNB binding was decreased compared with that of SAM-R/1 at the same age. Single and repeated administrations of bifemelane to SAM-P/8 induced an increase in the Bmax of [3H]QNB binding in the hippocampus. From these results, bifemelane seems to exert pharmacological effects through possible activation of the cholinergic system in the hippocampus of SAM.