Progress in calcium regulation in myocardial and vascular ischemia-reperfusion injury / 生理学报

Ischemia-reperfusion injury (IRI) has been recognized as a serious problem for therapy of cardiovascular diseases. Calcium regulation appears to be an important issue in the study of IRI. This article reviews calcium regulation in myocardial and vascular IRI, including the calcium overload and calcium sensitivity in IRI. This review is focused on the key players in Ca(2+) handling in IRI, including membrane damage resulting in increase in Ca(2+) influx, reverse-mode of Na(+)-Ca(2+) exchangers leading to increased Ca(2+) entry, the decreased activity of sarcoplasmic reticulum (SR) Ca(2+)-ATPase causing SR Ca(2+) uptake dysfunction, and increased activity of Rho kinase. These key players in Ca(2+) homeostasis will provide promising strategies and potential targets for therapy of cardiovascular IRI.

Effect of ischemia/hypoxia on mesenteric vasomotor function in spontaneously hypertensive rats and its possible mechanism / 生理学报

Hypertension is a common cardiovascular disease and can induce many complications, such as stroke and coronary heart disease. The purpose of the present study was to investigate the effect of ischemia/hypoxia on mesenteric artery vasomotor function in spontaneously hypertensive rats (SHR). Rat mesenteric arterial rings were cultured in modified ischemia-mimetic solution in a hypoxia incubator for a certain time period. Isometric tension changes of isolated mesenteric arterial rings were recorded continuously by a myograph system. The results obtained were as follows: In SHR group, the maximum contractions to KCl and phenylephrine (PE) were increased, and the maximum relaxation to acetylcholine (ACh) was decreased, compared to those in Wistar-Kyoto (WKY) rats group. Compared with SHR group and WKY with acute ischemia/hypoxia (WKY+H) group, SHR with acute ischemia/hypoxia (SHR+H) increased the maximum contractions induced by KCl and PE and inhibited the maximum relaxations by ACh. In SHR+H and SHR groups, the vasodilation induced by ACh was unaffected by N(G)-nitro-L-arginine methylester (L-NAME), whereas in WKY group, the relaxation to ACh was attenuated by L-NAME. CaCl2-induced contraction in depolarized rings in SHR+H group significantly shifted to the left compared with SHR group. In Ca(2+)-free K-H solution, the maximum contractions induced by PE and caffeine were increased in SHR+H group compared to those in WKY+H group; the PE- and caffeine-induced contractions were also enhanced in SHR group versus WKY group; the maximum contraction induced by PE was significantly increased in SHR+H group versus SHR group. These findings suggest that acute ischemia/hypoxia aggravates mesenteric artery dysfunction in SHR. The mechanism may be related to the decreased NO generation and increased sarcoplasmic reticulum Ca(2+) release.