[Effect of Bay K 8644 on arteriole smooth muscle cell membrane potential in rats with severe hemorrhagic shock].
OBJECTIVE
To investigate the effect of Ca(2+) influx through L-type Ca(2+) channels on normal and hyperpolarized membrane potential of arteriole smooth muscle cells (ASMCs) in rats.


METHODS
The ASMCs isolated from normal rats and those with severe hemorrhagic shock were labeled with DiBAC4 (3) for membrane potential detection.


RESULTS
Ca(2+) influx caused hyperpolarization of the membrane potential in the normal ASMCs but depolarization in the cells from rats with hemorrhagic shock, and this effect could be inhibited by TEA.


CONCLUSIONS
Ca(2+)-activated potassium channels activated by Ca(2+) influx through L-type Ca(2+) channels in normal ASMCs to cause hyperpolarization but leads directly to membrane potential depolarization in ASMCs from rats with severe hemorrhagic shock. This finding can be meaningful for treatment of vascular hyporeactivity in advanced stage of severe shock.
Zhao
Qing
Q
Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China. qingzhao@fimmu.com
Zhao
Ke-sen
KS
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000503:physiopathology; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000378:metabolism; D005260:Female; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012771:Shock, Hemorrhagic / Q000503:physiopathology*
D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D024681:Potassium Channels, Calcium-Activated; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester