ABSTRACT
In the isolated rabbit aorta, like verapamil ( Ver ) anisodamine ( Ani ) might inhibit the contraction induced by phenylephrine ( PE ) and high K+ with IC50 value of 120 and 86 ? mol/L, respectively. PE/K+ ratio of IC50 was 1.4 which was less than that of Ver. It showed that although PDC may be more sensitive to Ani than ROC, the difference in sensitivity of Ani on 2 calcium chan- nel are less marked than that of some calcium antagonists. Ani had inhibitory effects on 2 contractile components of serotonin (5-HT ) . Ani and Ver could obviously inhibit post-resting potentiatipn and staircase phenomenon in guinea pig atria. Ani also might inhibit the contraction induced by calcium and shift concentration-response nonparallelly to right on both tissues above.The results suggest that Ani possesses nonspecific calcium antagonistic effect and reduces the tension by affecting PDC and ROC to decrease extracellular calcium influx and inhibiting intracellular calcium release.