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Electrophysiological effects of hydrogen sulfide on guinea pig papillary muscles {sl in vitro}

Xu Meng, Wu Yuming, Li Qian, Wang Fuwei, He Ruirong

Department of Physiology,Institute of Basic Medicine,Hebei Medical University.Shijiazhuang 050017,Hebei

Abstract

The cardiac electrophysiological effects of hydrogen sulfide (H_(2)S) were examined in guinea pig papillary muscles in vitro using intracellular microelectrode technique. The results obtained were as follows: (1) the duration of action potential (APD) in the normal papillary muscles was decreased by NaHS (H_(2)S donor, 50, 100, 200 #mu#mol/L) in a concentration-dependent manner; (2) in partially depolarized papillary muscles, 100 #mu#mol/L NaHS not only reduced APD, but also decreased the amplitude of action potential (APA), overshoot (OS) and maximal velocity of depolarization at phase 0 (V_(max)); (3) pretreatment with ATP-sensitive K~(+) (K_(ATP)) channel blocker glibenclamide (20 #mu#mol/L) partially blocked the effects of NaHS (100 #mu#mol/L); (4) pretreatment with L-type Ca~(2+) channel agonist Bay K8644 (0.5 #mu#mol/L) also partially blocked the effects of NaHS (100 #mu#mol/L); (5) pretreatment with Ca~(2+)-free KrebsHenseleit solution containing glibenclamide (20 #mu#mol/L) completely blocked the effects of NaHS (100 #mu#mol/L); (6) APD in the normal papillary muscles was increased by DL-propargylglycine (PPG, an inhibitor of cystathionine #gamma#-lyase, 200 #mu#mol/L). All these results suggest that the electrophysiological effects of H_(2)S on papillary muscles in our study are due to an increase in potassium efflux through the opening of K_(ATP) channels and a decrease in calcium influx. Endogenous H_(2)S may act as an important regulator in electrophysiological characters in papillary muscles.

Key words: electrophysiological;hydrogen sulfide;Action potential;papilary muscles

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Citing This Article：

Xu Meng, Wu Yuming, Li Qian, Wang Fuwei, He Ruirong. Electrophysiological effects of hydrogen sulfide on guinea pig papillary muscles {sl in vitro}. Acta Physiol Sin 2007; 59 (2): 215-220 (in Chinese with English abstract).