[Attenuation of acetylcholine-induced hyperpolarization of aortic endothelial cells in rats fed by high-salt diet and its correction with enalapril].
High-salt diet is known to result in attenuation of endothelium-dependent relaxation in rat aorta. We investigated the possible alterations in electrical responses of rat aortic endothelial cells to acetylcholine as one of the eventual mechanisms that lead to inhibition of endothelium-dependent relaxation induced by high-salt diet. It was shown that endothelial resting membrane potential in rats fed by high-salt diet did not differ significantly from that observed in the control group (-40.6+/-2.3 mV and -41.2+/-0.9 mV, respectively). The amplitude of acetylcholine-induced hyperpolarization of endothelial cells in rats fed by high-salt diet was significantly attenuated (9.0+/-1.5 mV vs 22.7+/-1.3 mV in the control group). The amplitude of hyperpolarization increased to 25.7+/-1.3 mV when high-salt diet was administered with enalapril, the angiotensin-converting enzyme inhibitor. We conclude that high-salt diet leads to attenuation of hyperpolarization of rat aortic endothelial cells in response to acetylcholine, that may mediate inhibition of NO synthesis and endothelium-dependent relaxation. Angiotensin-converting enzyme inhibitor enalapril prevents the observed alterations in endothelial electrical responses induced by high-salt diet.
Bondarenko
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OI
Sahach
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VF
D000109:Acetylcholine / Q000494:pharmacology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004656:Enalapril / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D051381:Rats; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*
D000806:Angiotensin-Converting Enzyme Inhibitors; D017673:Sodium Chloride, Dietary; D004656:Enalapril; D000109:Acetylcholine