Background L-type calcium channel participates in the regulation of a variety of physical and pathological process. In vasculature, it mainly mediated agonist-induced vascular smooth muscle contraction. However, it is not clear whether there are differences in L-type calcium channel mediated vessel responses to certain vasoconstrictors among different species. Methods The coronary arteries were dissected from the heart of rats and mice respectively. The coronary arterial ring contraction was measured by Multi Myograph System. Results Endothelin-1, U46619 and 5-HT could produce concentration-dependent vasoconstriction of coronary arterial rings from rats and mice. Compared with rats, the vessel rings of mice were more sensitive to ET-1 and U46619, and less sensitive to 5-HT. The L-type Ca2~ channel blocker nifedipine could significantly inhibit the coronary artery contractions induced by ET-1, U46619 and 5-HT. The inhibitory effect of i ixM nifedipine on ET-1 and 5-HT-induced coronary artery contractions were stronger in mice than in rats, but its effect on U46619 induced-vessel contractions was much weaker in mice than in rats. Conclusions L-type Ca2＋ channel plays an important role in the coronary arterial contraction, but the responses to vasoconstrictor and L-type Ca2＋ channel blocker are different between rats and mice, thus suggesting that the coronary arteries of rats and mice have different biological characteristics.
Background MicroRNAs （miRNANAs） are endogenous, small non-coding RNAs that negatively regulate gene expression in diverse cardiovascular diseases. However, the roles of miRNANAs in atherosclerogenesis needs to be elucidated. In the present study, the effect of miRNA-21 on pro-atherosclerotic genes expression was examined. Methods The pro-atherosclerotic genes including COX2, VCAM1, ICAM1, MCP1 and miRNA-21 were detected in ox-LDL-treated mouse macrophage RAW264.7 cells. ApoE knock-out （ApoE- KO） mice were fed with high-fat diet for 16 weeks, and the abdominal aorta were fixed and used for miRNA- 21 hybridization. Lentivirus-based vectors for enforced expression of miRNA-21 and antisense miRNA-21were prepared. The expression of proatherosclerotic genes was determined in the RAW264.7 cells with lentivirus- mediated up-regulation of miRNA-21. Results COX2, VCAM1, ICAM1 and MCP1 could be up-regulated by ox-LDL treatment, and 50 Ixg/mL ox-LDL could significantly increase the expression of above four genes in ox-LDL EAW264.7 cells, miRNA-21 could also be markedly up-regulated in ox-LDL-induced RAW264.7 cells. The result of miRNANA hybridization showed that miRNA-21 was strongly expressed in atherosclerotic plaques but not in normal aorta. Lentivirus-mediated over-expression of miRNA-21 could significantly enhance expressions of COX2, VCAM1, ICAM1 and MCP1 in RAW264.7 cells, which could be reversed by antisense miRNA-21 mediated by lentivirus vector. Conclusions miRNA-21 could be modulated by ox-LDL in macrophage RAW264.7 cells, and miRNA-21 could enhance COX2, VCAM1, ICAM1 and MCP1 expressions in macrophages.
