Involvement of sensory nerves in vasodilator responses to acetylcholine and potassium ions in rat hepatic artery

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Abstract

In the presence of ouabain (1 mM), acetylcholine and KCl (5 mM) evoked endothelium-independent relaxations in rat hepatic arteries. Treatment with capsaicin (10 μM), scopolamine (1 μM) or CGRP8-37 (3 μM) prevented these relaxations. Acetylcholine-induced relaxations in intact arterial segments in the presence of indomethacin (10 μM) and N(G)-nitro-L-arginine (0.3 mM) were only partially inhibited by ouabain plus BaCl2 (30 μM). However, ouabain plus BaCl2 almost abolished such relaxations in capsaicin-pre-treated preparations. In arteries without endothelium, the neurosecretagogue α-latrotoxin (1 nM) induced complete relaxations, which were abolished by CGRP8-37 or pre-treatment with capsaicin. α-Latrotoxin also induced a smooth muscle hyperpolarization (12 ± 2 mV), which was abolished by CGRP8-37. The ability of ouabain to disclose a CGRP-mediated neurogenic relaxation must be considered when this agent is used as a pharmacological tool. The results further suggest that CGRP is a nerve-derived hyperpolarizing factor in the rat hepatic artery.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmacology and Toxicology

Keywords

  • Endothelium-derived hyperpolarizing factor, Endothelium-derived relaxing factors, Hyperpolarization, Membrane potential, Nitric oxide, Potassium channels, Vascular endothelium
Original languageEnglish
Pages (from-to)27-32
Number of pages6
JournalBritish Journal of Pharmacology
Volume130
Issue number1
Publication statusPublished - 2000 Jan 1
Publication categoryResearch
Peer-reviewedYes