ABSTRACT
The effects of nicorandil ( NICO ) on the contractility, automati -city, excitability, functional refractory period ( FRP ) & dose-response curves for isoprenaline as well as calcium were studied in guinea pig papillary muscles. NICO could decrease the amplitude of contraction of papillary muscles dose-dependently. Propranolol and NICO might antagonize the inotropic effect of isoprenallne. Verapamil & NICO induced Ca2+ antagonistic effects in a non-competitive manner, & the maximal Ca2+ response of papillary muscles decreased signifi- cantly. The automaticity of papillary muscles was decreased Significantly when the concentration of NICO reached 1.4 mmol/L, but exerted no effect on their excitability & the functional refractory period.
ABSTRACT
Intravenous injection of SPD 10 mg/kg could increase the tolerant dose of ouabain, and prevent the arrhythmias induced by acute myo-cardial ischemia in rats and that elicited by adrenaline-chloroform model in rabbits. SPD 60 mg/kg intraperitoneally could abolish the ventricular fibrillation produced by chloroform inhalation in mice. It inhibited the contractility, prolonged the functional refractory period and decreased the automaticity significantly of the isolated guinea pig papillary muscles, but no significant effect on excitability.
ABSTRACT
This paper reported that lidocaine given intravenously 5mg/kg 9 min before occlusion of left ventricular coronary artery (CO) may shorten the latent period for ventricular arrhythmias from 6.2?1.9 min to 3.7?0.9 min (P