抄録
Both bethanechol and physostigmine produced dose-dependent negative chrono-, dromo- and inotropic effects in the dog isolated atrial preparation. Within a relatively small dose of bethanechol and physostigmine, negative inotropic effect was clearly induced but no significant chrono- and dromotropic changes were observed. With a relatively large dose, the two cholinomimetics caused negative chrono-, dromo- and inotropic effects. The order of the negative actions of the drugs in % changes was inotropism >dromotropism≥chronotropism. These results indicate that pacemaker activity, sinoatrial conductivity and atrial contractility may be differentially sensitive to actions of cholinomimetics.
