Effects of captopril and enalapril on intracellular Ca2+ in vascular smooth muscle cell.
OBJECTIVE
To determine whether angiotensin-converting enzyme inhibitors can affect Ca2+ handling in cultured aortic smooth muscle cells (ASMC) directly.


METHODS
Cultured ASMC derived from rat aorta were loaded with the intracellular Ca2+ ([Ca]2+i) fluorescent indicator Fura 2-AM and digital image processing technique was used.


RESULTS
Resting [Ca2+]i was greater in ASMC from SHR vs WKY (P < 0.01). KCl-, norepinephrine (NE)-, and angiotensin II (Ang)-induced [Ca2+]i increases were enhanced in ASMC of SHR vs WKY (220 +/- 6, 212 +/- 8, and 215 +/- 14 vs 199 +/- 6, 202 +/- 7, and 195 +/- 7 nmol.L-1, respectively). Captopril (Cap) and enalapril (Ena) had no inhibitory effect on KCl-, NE-, and Ang-induced [Ca2+]i increases in ASMC of WKY. Cap and Ena inhibited KCl-, NE-, and Ang-increased [Ca2+]i in ASMC of SHR (210 +/- 7, 194 +/- 6, and 201 +/- 6 nmol.L-1, respectively). Ena and nifedipine similarly decreased KCl-, NE-, and Ang-increased [Ca2+]i.


CONCLUSIONS
Cap blocked KCl-, NE-, and Ang-increased ([Ca2+]i) via a voltage-dependent Ca2+ channel of which function and specificity was altered in ASMC of SHR.
Qi
J H
JH
Department of Pharmacology, Shanghai Second Medical University, China.
Zhang
L
L
Wang
J
J
Wei
P J
PJ
Gu
P K
PK
Jin
Z J
ZJ
Huang
M Z
MZ
Wang
H Y
HY
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D002216:Captopril / Q000494:pharmacology*; D002478:Cells, Cultured; D004656:Enalapril / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D002216:Captopril; D002118:Calcium