期刊
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
卷 289, 期 5, 页码 H2244-H2250出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00254.2005
关键词
hyperpolarization; membrane potential; vasomotor function; reactive oxygen species
资金
- NHLBI NIH HHS [HL-62984, HL-55006, HL-38901, HL-16066] Funding Source: Medline
- NIDDK NIH HHS [DK-54759, DK-15843, DK-52617] Funding Source: Medline
- NINDS NIH HHS [NS-24621] Funding Source: Medline
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 mu M) inhibited both hyperpolarization and relaxation to X/XO and SNP, and uric acid (100 mu M) inhibited relaxation. Glibenclamide (1 mu M) 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.
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