科研之友
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摘要
Aim To investigate the mechanism of Ca2 + handling involved in constriction of coronary arteries in C57BL/6 mice. Coronary artery contractions induced by vasoconstrictors were measured using the Multi Myograph System, and the responses to different blockers were observed in diabetic mice. Results The contraction of coronary artery was mainly mediated by L type calcium channel and Ca2r release from the sarcoplasmic reticulum of VSMCs, and the store-operated calcium channel did not mediate it. 5-HT and U46619 induced concentration-dependent vasoconstriction in coronary arteries of diabetic mice, and the constrictions elicited by different agonists were markedly reduced compared with control (P<0.01).The vasoconstrictions evoked by 5-HT and U46619 were significantly reduced in coronary artery after incubation with nifedipine. And the inhibition rate of nifedipine on the diabetic mice. Methods Diabetic model was established by intraperitoneal injection of streptozotocin into coronary artery contractile response of diabetic mice was significantly lower than that of wild-type mice (P <0.01), In Ca2+free solution containing nifedipine, the responses to different vasoconstrictors in diabetic mice were markedly lower than those in wild-type mice (P<0.01). The high potassium-elicited contractions in diabetic mice significantly decreased compared with control (P <0.01 ). Conclusions The responses to vasoconstrictors in coronary artery of diabetic mice are significantly reduced, which is associated with the down-regulation of L-type calcium channel and Ca2+ release from the SR of VSMCs. ? 2020 Publication Centre of Anhui Medical University.
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