利血平与戊脉安对豚鼠左心房的作用比较

利血平具有浓度依赖性负性肌力作用。对异丙肾上腺素量-效反应的影响与戊脉安相似,不同于β-受体竞争性拮抗剂心得安.对Ca~(2+)量-效反应的影响与戊脉安相似,表现为非竞争性拮抗作用,还具有频率依赖性负性肌力反应.结果说明利血平对豚鼠左心房肌的作用与戊脉安相似,可能具有Ca~(2+)拮抗作用.

COMPARISON OF THE EFFECTS OF RESERPINE WITH VERAPAMIL ON THE LEFT AURICLE OF GUINEA PIG

The introvenous or intromuscular injection of reserpine can acutely decrease blood pressure and reduce. the contractile force of cardiac muscles.In order tostudy the mechanism of these actions this paper reportsits negative inotropic effects in comparison withverapamil and its effects on the dose-reponse curvesof isoproterenol and calcium and the frequency-force re-lationship in the left auricle of guinea pig.Reserpine pos-sesses dose-dependent negative inotropic on the leftauricle of guinea pig.The potency of reserpine to thatof verapamil was 1:189.Similar to verapamil but differ-ent from propranolol,reserpine shifted the isoprenalinedose-reponse curve non-parallelly to the right with adecrease of its a decrease of its maximum effect.Reserpine and verapamil shifted the calciumdose-response curve non-parallelly to the right and de-cresed their maximum effect.Reserpine producted fre-quency-dependent depression of contratile in the leftauricle of guinea pig in the presence of reserpine andverapamil,th depression of the contractile force was more pronounced at high than at low frequencies.It isconcluded that the effects of reserpine on the leftauricle of guinea pig are similar to those of verapamil,and are antagonistic to Ca~(2 ).