Hydrogen sulfide donors in the cardiovascular system
Since the evolution of H2S as an essential gasotransmitter at cellular level, and based on the fact that H2S characteristically similar to NO; researchers aimed to investigate the physiological effects of H2S on cardiovascular system, proposing that H2S donors may become a potential treatment for various cardiovascular abnormalities including atherosclerosis, hypertension, vasoconstriction and cellular apoptosis induced by reactive oxygen species [24-26]. The cellular mechanism by which H2S induce cardiovascular effects is not well illustrated yet. A recent study suggested that H2S can reduce heart rate and blood pressure through KATP ...view middle of the document...
L-type calcium channel inhibition
The release of calcium from the sarcoplasmic reticulum plays an essential role in cardiomyocytes excitability and contraction, and the influx of calcium through L-type calcium channels is a crucial determinant of intracellular calcium amount as well. Thus, L-type calcium channels has been recognized as an effective treatment for various cardiovascular disorders include myocardial ischemia, arrhythmias, hypertension and heart failure.
The first evidence of the influence of H2S donor on L-type calcium channels carried out by Sun and associates on isolated cardiomyocytes of spontaneously hypertensive and rats . Their study found that NaHS (H2S donor) significantly (p< 0.05) reduced the peak of L-type calcium channel current by average of 19.61 % in isolated cardiomyocytes. In addition; NaHS associated with significant (P< 0.05) reduction on the time to 25, 50, and 90% repolarization when compared to control. Based on these results the authors concluded that H2S is a novel inhibitor of L-type calcium channels in cardiomyocytes but required further investigation as a potential treatment for different cardiovascular diseases contributed in calcium homeostasis.
The high mortality rate associated with myocardial infarction reduced significantly with proper treatment and management [27-28]. H2S constitute a new treatment pathway in myocardial infarction through Vasorelaxation, decreasing oxygen consumption and preventing myocardial apoptosis. A group of researchers induced myocardial infarction surgically on 80 rats and divided them into three groups receiving either vehicle, 14 micro mol/kg of NaHS (H2S donor), or 50 mg/kg propargylglycine (Irreversible inhibitor of CSE; the main H2S synthesizing enzyme in cardiomyocytes) daily for 1 week before MI inducement surgery and 2 days pot surgery. After confirming myocardial infarction by electrocardiography, propargylglycine treated group showed the highest infarct size/total area of myocardium while NaHS treated group had the lowest infarction size (62.9 %, 52.9% and 43.4 %, p< 0.05 between al groups). The size of infarction was further translated to mortality rate when NaHS group had the least mortality rate among three groups followed by control and finally propargylglycine showed the highest mortality rate again (27.5%, 35% and 40%, p< 0.05 between all groups).
Epidemiological studies have shown that the possibility of heart failure post myocardial may reach 24% - 40%, which is mainly started in a form cardiomyocytes apoptosis prior functional heart failure [30-32]. Several studied aimed to investigate cardioprotective characteristics of H2S In animal model of heart failure [33,39]. In order to elucidate the cardiomyocytes protective feature of H2S; a group of researchers tested the effects of NaHS and propargylglycine among Male Sprague–Dawley rats induced to heart failure post acute myocardial infarction surgery. Animals...