抄録
Using a direct in situ perfusion technique of the AV node artery, the effect of bethanechol, a selective muscarinic stimulant, was investigated in 18 mongrel dogs and compared with other muscarinic stimulants, methacholine and carbachol which are used clinically. The injection of bethanechol into the AV node artery induced various degrees of AV block. The threshold dose was 1 to 3μg. for inducing a second degree of AV block. More than 10μg. of bethanechol induced long lasting complete AV block. When complete AV block was induced, a constant rate of 32±2.1 (mean±S.E.) beats/min. of nodal rhythm was obtained in 15 cases. During complete AV block, atrial fibrillation was occasionally induced and also ventricular tachycardia at a rate of 110±5.8 (mean±S.E.) beats/min. (n=11). These effects of bethanechol were similar to those of methacholine or carbachol.
