results claim that H2S may inhibit L type calcium currents depending on the sulfhydryl group in rat cardiomyocytes. In addition to the carbon monoxide and gasotransmitters nitric-oxide, hydrogen order FK866 sulfide could be the next biologic indication gaseous molecule and is considered as a crucial physiologic regulator in the circulatory, anxious, endocrine and immune systems. Within the study of broad bodily functions, the cardio protective effect of H2S was first found and drew much attention in the area of life sciences. H2S may be endogenously generated from cysteine by the cystathionine U lyase molecule within the cardiovascular system. In vitro and in vivo studies showed that H2S induced bad cardiac inotropic effects and played a cardio-protective role in various models of diseases. It had been also found that exogenous H2S post conditioning played a protective function in chronic heart failure and effectively secured isolated rat hearts against ischemia reperfusion injury. However, the process responsible for the bad cardiac inotropic effects of H2S hasn’t been Cellular differentiation fully understood. L type calcium channels are critical in the excitation contraction coupling in cardiomyocytes, and they supply the main pathway through which Ca2 enters into myocardial cells, therefore, the Ca2 entering through these channels might trigger the Ca2 induced Ca2 release. The total amount of Ca2 released from intracellular calcium stores and the Ca2 entering the sarcoplasmic reticulum from outside the cells maintain intracellular calcium homeostasis, which plays significant position in myocardial physiology and pathology. et al. demonstrated that H2S could hinder L order Celecoxib type calcium channels in cardiomyocytes. However, the potential targeting website on Ltype calcium channels has not been solved. H2S is more potently toxic than cyanide as it blocks cytochrome C oxidase that leads to mitochondrial respiration inhibition. The change of disulfide bridges in to groups of the cysteine containing proteins in the heart of cytochrome C oxidase was seen as the process for intoxication of H2S. Toxicological studies showed that pre treatment with oxidized glutathione or methemoglobinemia can defend fresh mammals against a subsequent deadly challenge from inorganic sulfide poisoning, alternately, a way of p intoxication of H2S involves holding free sulfide which might prevent it from reaching a vital enzymatic site. Ergo, the disulfide bridges or the sulfhydryl groups of the cysteine containing proteins could be the targets of H2S. Meanwhile, the sub-units of the L type calcium channel and ATP sensitive and painful potassium channel were found to contain functionally essential free sulfhydryl groups that regulate gating. Therefore, we hypothesized that a novel mechanism of activation of the channels might have an accommodating entrance on the channels mentioned above with Cys SH and that H2S might resulted from the formation of a disulfide bridge between cysteine residues of the pore as the critical target.