Species-specific differences in the role of L-type Ca²⁺ channels in the regulation of coronary arterial smooth muscle contraction.
The L-type calcium channel (LCC) plays a regulatory role in various physical and pathological processes. In the vasculature, LCCs mediate agonist-induced vascular smooth muscle contraction. However, whether LCC-mediated vessel responses to certain vasoconstrictors vary among species remains unclear. The coronary arteries were dissected from the hearts of rats and mice. Coronary arterial ring contraction was measured using the Multi Myograph system. High K+ (60 mM)-induced coronary artery contractions were stronger in rats than in mice, whereas CaCl2-induced contraction curves did not differ significantly between the two groups. Endothelin-1, U46619 (thromboxane A2 receptor agonist), and 5-hydroxytryptamine (5-HT) induced concentration-dependent vasoconstriction of coronary arterial rings in rats and mice. The vessel rings of mice were more sensitive to ET-1 and U46619 and less sensitive to 5-HT than those of rats. The LCC blocker nifedipine significantly inhibited coronary artery contractions induced by ET-1, U46619, and 5-HT. The inhibitory effect of 1 μM nifedipine on ET-1- and 5-HT-induced coronary artery contractions was stronger in mice than in rats, whereas its effect on U46619-induced vessel contractions was weaker in mice than in rats. The 5-HT2A receptor and LCC mRNA levels were higher in the coronary arteries of rats than in those of mice, whereas the expressions of the ETA and TXA2 receptors and Orai1 mRNA levels were comparable between the two groups. LCC plays an important role in coronary arterial contraction. Rats and mice show different responses to vasoconstrictors and LCC blockers, suggesting that the coronary arteries of rats and mice have different biological characteristics.
Hui
H
Yang
Su-Juan
SJ
Kuang
Fang
F
Rao
Yu-Mei
YM
Xue
Xiao-Ying
XY
Liu
Zhi-Xin
ZX
Shan
Xiao-Hong
XH
Li
Jie-Ning
JN
Zhu
Zhi-Ling
ZL
Zhou
Xiao-juan
XJ
Zhang
Qiu-Xiong
QX
Lin
Xi-Yong
XY
Yu
Chun-Yu
CY
Deng
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D003331:Coronary Vessels / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009213:Myography; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D014662:Vasoconstrictor Agents