NEGATIVE EFFECTS OF ETHANOL ON ISOLATED GUINEA PIG LEFT ATRIUM AND PAPILLARY MUSCLES

Objective To investigate the effects of ethanol on physiological characteristics of the isolated guinea pig left atrium and papillary muscles.Methods The effects of ethanol on contractility, post-rest potentiation and positive staircase phenomenon were observed in isolated left atrium and papillary muscles of guinea pig.Results Ethanol(50.0,100.0,200.0mmol·L -1)prominently inhibited the contraction of papillary muscles. Ethanol(12.5,25.0,50.0,100.0,200.0mmol·L -1) inhibited the contraction of left atrium, and markedly decreased the post-rest potentiation of myocardial contractility in left atrium. High concentration of ethanol(100,200mmol·L -1) depressed the positive staircase phenomenon of isolated guinea pig left atrium.Conclusion These results suggest that ethanol induces inhibitory effects of the contractility, post-rest potentiation, positive staircase phenomenon of left atrium. The mechanism by which ethanol induces the negative inotropic effects may be related to decrease the amount of calcium released from the intracellular stores.