The carbachol-stimulated [~35S]GTP r S binding method was used to observe theeffect of ZMS

an active component from Zhimu

on the coupling of M-receptor toG-protein. The effect of ZMS on the ability of learning and memory in aged rats wasalso observed. It was shown that the carbachol-stimulated elevation of [~35S]GTP r Sbinding was significantly decreased in aged rats as compared with young rats. Thecarbachol-induced [~35S]GTPr S binding showed that administration of ZMS atmedian or high dose have a definite elevation effect on the coupling activity ofM-receptors to G-protein in brain

and this elevation was accompanied by animprovement of learning and memory ability.