Effects of m-nisoldipine on contraction and 45Ca influx in isolated rat aorta.
m-Nisoldipine caused a concentration-dependent depression of the contractile response and 45Ca influx evoked by KCl in isolated rat thoracic aorta. The IC50 value for contraction and 45Ca influx were 0.69 (95% confidence limits 0.32-1.5) nmol.L-1 and 0.35 (95% confidence limits 0.06-2.0) nmol.L-1, respectively. There was a positive correlation between the inhibition of KCl-evoked contraction and 45Ca influx (r = 0.996). m-Nisoldipine (0.1-10 mumol.L-1) did not influence the 45Ca influx into resting cells and failed to inhibit noradrenaline (1.0 mumol.L-1)-evoked contraction and 45Ca influx. The results suggest that the relaxant effect of m-nisoldipine on rat aorta may be closely related to the blockade of Ca2+ entry through a potential-dependent calcium channel.
Zhou
B J
BJ
Department of Pharmacology, Hebei Medical College, Shijiazhuang, China.
Li
Y S
YS
Fu
S X
SX
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D005260:Female; D007536:Isomerism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D015737:Nisoldipine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015737:Nisoldipine; D002118:Calcium