Peroxynitrite hyperpolarizes smooth muscle and relaxes internal carotid artery in rabbit via ATP-sensitive K+ channels

Masuo Ohashi; Frank Faraci; Donald Heistad

doi:10.1152/ajpheart.00254.2005

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Peroxynitrite hyperpolarizes smooth muscle and relaxes internal carotid artery in rabbit via ATP-sensitive K+ channels

Journal article

Peer reviewed

Peroxynitrite hyperpolarizes smooth muscle and relaxes internal carotid artery in rabbit via ATP-sensitive K+ channels

Masuo Ohashi, Frank Faraci and Donald Heistad

American journal of physiology. Heart and circulatory physiology, Vol.289(5), pp.H2244-2250

11/2005

DOI: 10.1152/ajpheart.00254.2005

PMID: 16219814

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Abstract

The goal of this study was to determine the effects of peroxynitrite (ONOO-) on smooth muscle membrane potential and vasomotor function in rabbit carotid arteries. ONOO- is known to affect vascular tone by several mechanisms, including effects on K+ channels. Xanthine (X, 0.1 mM), xanthine oxidase (XO, 0.01 U/ml), and a low concentration of sodium nitroprusside (SNP, 10 nM) were used to generate ONOO-. In the common carotid artery, X and XO (X/XO) in the presence of SNP tended to increase tension. In contrast, in the internal carotid artery, X/XO in the presence of SNP transiently hyperpolarized the membrane (-8.5 +/- 1.8 mV, mean +/- SE) and decreased tension (by 85 +/- 5.6%). In internal carotid arteries, in the absence of SNP, X/XO did not hyperpolarize the membrane and produced much less relaxation (by 23 +/- 5.6%) than X/XO and SNP. Ebselen (50 microM) inhibited both hyperpolarization and relaxation to X/XO and SNP, and uric acid (100 microM) inhibited relaxation. Glibenclamide (1 microM) abolished hyperpolarization and inhibited relaxation during X/XO and SNP. Charybdotoxin (100 nM) or tetraethylammonium (1 mM) did not affect hyperpolarization or relaxation, respectively. These results suggest that ONOO- hyperpolarizes and relaxes smooth muscle in rabbit internal carotid artery but not in common carotid artery through activation of K(ATP) channels.

Catalase - pharmacology

Reactive Oxygen Species - metabolism

Carotid Artery, Internal - drug effects

Potassium Channels - physiology

Male

Organoselenium Compounds - pharmacology

Glyburide - pharmacology

Charybdotoxin - pharmacology

Potassium Channels, Calcium-Activated - metabolism

Potassium Channel Blockers - pharmacology

Muscle, Smooth, Vascular - drug effects

Membrane Potentials - drug effects

Rabbits

Superoxide Dismutase - pharmacology

Muscle Tonus - drug effects

Antioxidants - pharmacology

Azoles - pharmacology

Potassium Channels - drug effects

Hydrogen Peroxide - metabolism

Hypoglycemic Agents - pharmacology

Tetraethylammonium Compounds - pharmacology

Animals

Peroxynitrous Acid - pharmacology

Uric Acid - pharmacology

Potassium Channels, Calcium-Activated - drug effects

Muscle Relaxation - drug effects

In Vitro Techniques

Details

Title: Subtitle: Peroxynitrite hyperpolarizes smooth muscle and relaxes internal carotid artery in rabbit via ATP-sensitive K+ channels
Creators: Masuo Ohashi - Cardiovascular Center and Dept. of Internal Medicine, Univ. of Iowa and Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1801, USA
Frank Faraci
Donald Heistad
Resource Type: Journal article
Publication Details: American journal of physiology. Heart and circulatory physiology, Vol.289(5), pp.H2244-2250
Publisher: United States
DOI: 10.1152/ajpheart.00254.2005
PMID: 16219814
ISSN: 0363-6135
eISSN: 1522-1539
Grant note: DK-54759 / NIDDK NIH HHS HL-16066 / NHLBI NIH HHS HL-38901 / NHLBI NIH HHS NS-24621 / NINDS NIH HHS DK-15843 / NIDDK NIH HHS HL-62984 / NHLBI NIH HHS DK-52617 / NIDDK NIH HHS HL-55006 / NHLBI NIH HHS
Language: English
Date published: 11/2005
Academic Unit: Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
Record Identifier: 9984040244602771

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