Effects of henbane drugs on electrophysiological and mechanical properties of guinea pig papillary muscle

The henbane drugs (HD) had similar effects on fast action potentials (AP) and contractile force (FC) of guinea pig papillary muscle. Either atropine (Atr) 50μmol/L or scopolamine (Sco) 0.3 mmol/L or anisodamine (Ani) 0.3 mmol/L could increase ERP/APD ratio, prolong CT and suppress FC. The spontaneous rhythms were almost abolished after treatment with Atr 10μmol/L，Sco 0.l mmol/L or Ani 0.l mmol/L, respectively. Slow AP was induced by isoprenaline or histamine (1μmol/L) after cardiac cells were depolarized in K+-rich (22 mmol/L) solution. Either Atr 0.1 mmol/L or Sco 0.6 mmol/L or Ani 0.6 mmol/L had partial inhibitory effect on both kinds of slow AP. The results suggest that comparative high concentration of HD possess antiarrhythmic effect and unspecific calcium channel-blocking effect.