AJP - Cell Physiology, Vol 273, Issue 3 C834-C842, Copyright © 1997 by American Physiological Society
Inhibition of oxidative phosphorylation, vascular tone, and [Ca2+]i in the perfused rat tail artery
N. N. Tran, A. Robert, J. Atkinson and C. Capdeville-Atkinson
Laboratoire de Pharmacologie Cardio-vasculaire, Faculte de Pharmacie, Universite Henri Poincare-Nancy 1, France.
We investigated the possibility that the inhibition of oxidative
phosphorylation in vascular smooth muscle attenuates norepinephrine- or
KCl-evoked vasoconstriction with no change in mobilization of intracellular
calcium concentration ([Ca2+]i). Experiments were performed in perfused
segments of the rat tail artery loaded with the intracellular calcium dye
fura 2, in the absence and presence of dinitrophenol or sodium cyanide;
inhibition of oxidative phosphorylation was evaluated from the fall in
intracellular ATP levels. The metabolic inhibitors reduced vasoconstriction
with no change in [Ca2+]i handling, suggesting that 1) inhibition of
oxidative phosphorylation attenuates vasoconstriction via a mechanism
downstream of [Ca2+]i, and 2) [Ca2+]i homeostasis (both increases and
decreases in [Ca2+]i) can be maintained in the presence of inhibitors of
oxidative phosphorylation.
