Electrophisiological Effects Of Estradiol With Progesterone On Action Potential And Contraction Of Guinea Pig Papillary Muscle

Objective: To study the effects of estradiol with progesterone on actionpotential(AP) and contraction of guinea pig papillary muscle.Methods: Using conventional glass microelectrode and mechanicalreceding of myocardial contraction.Results: E₂ or P slowed down the maximal rate of rise of phase 0 (Vmax)of AP, decreased the action potential amplitude(APA), prolonged APduration(APD9o and APD) and ERP ,decreased the maximal isometrictension.Conclusion: All the results suggested that E₂ or P inhibits the k+channels may be also the Ca2+ channels of guinea pig papillary muscle.Pcan strenghten E₂ in some degree.