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Titolo:
Magnesium modulates contractile responses of rat aorta to thiocyanate: A possible relationship to smoking-induced atherosclerosis
Autore:
Li, WY; Zheng, T; Altura, BT; Altura, BM;
Indirizzi:
SUNY Hlth Sci Ctr, Hlth Sci Ctr, Dept Physiol, Brooklyn, NY 11203 USA SUNYHlth Sci Ctr Brooklyn NY USA 11203 t Physiol, Brooklyn, NY 11203 USA SUNY Hlth Sci Ctr, Hlth Sci Ctr, Dept Med, Brooklyn, NY 11203 USA SUNY Hlth Sci Ctr Brooklyn NY USA 11203 Dept Med, Brooklyn, NY 11203 USA SUNY11203 Sci Ctr, Hlth Sci Ctr, Ctr Cardiovasc & Muscle Res, Brooklyn, NYSUNY Hlth Sci Ctr Brooklyn NY USA 11203 iovasc & Muscle Res, Brooklyn, NY
Titolo Testata:
TOXICOLOGY AND APPLIED PHARMACOLOGY
fascicolo: 1, volume: 157, anno: 1999,
pagine: 77 - 84
SICI:
0041-008X(19990515)157:1<77:MMCROR>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
VASCULAR SMOOTH-MUSCLE; ENDOTHELIUM-DEPENDENT DILATION; CARDIOVASCULAR RISK-FACTORS; CIGARETTE-SMOKING; CAROTID ATHEROSCLEROSIS; SEXUAL DIMORPHISM; YOUNG-PEOPLE; CALCIUM; CELLS; ARTERY;
Keywords:
thiocyanate; extracellular magnesium ions; intracellular free calcium ions; rat aortic smooth muscle cells; vasospasm; atherosclerosis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Li, WY SUNY Hlth Sci Ctr, Hlth Sci Ctr, Dept Physiol, Brooklyn, NY 11203 USA SUNY Hlth Sci Ctr Brooklyn NY USA 11203 ol, Brooklyn, NY 11203 USA
Citazione:
W.Y. Li et al., "Magnesium modulates contractile responses of rat aorta to thiocyanate: A possible relationship to smoking-induced atherosclerosis", TOX APPL PH, 157(1), 1999, pp. 77-84

Abstract

Thiocyanate anions (SCN-) as the end products of tobacco smoke and found in the blood of cigarette smokers have been implicated in atherogenesis and heart diseases. Magnesium deficiency has also been implicated in the etiology of atherogenesis. The contractile responses of rat aorta to SCN- and themodulation of extracellular magnesium ions ([Mg2+](o)) on the effect of SCN- were, therefore, studied in isolated rat aortic rings. SCN- exposure at a range of concentrations (from 10(-5) to 5 x 10(-2) M) induces contractileresponses of isolated rat aortic rings with and without endothelium in a concentration-dependent manner. Significant differences in responsiveness toSCN- were found in rat aortic ring segments with and without endothelial cells. Preincubation of these vessels with low [Mg2+](o) markedly shifted the contractile concentration-effect curves to the left, and the contractile effects of SCN- in rat aortic rings were potentiated. In contrast to lowering [Mg2+](o), increasing [Mg2+](o) to 2.4 mM was found to dramatically attenuate the contractile responses to SCN-. In the absence of extracellular Ca2+ ([Ca2+](o)), SCN--induced contractions were, however, almost abolished after exposure to Mg2+-free medium. In order to investigate the mechanisms of [Mg2+](o) modulation of SCN--induced contractile response of rat aorta, changes in intracellular Ca2+ ([Ca2+](i)) were measured in cultured primary smooth muscle cells isolated from rat aorta. The resting level of [Ca2+](i)in the rat aortic smooth muscle cells was 80.6 +/- 6.6 nM. Exposure of these cells to SCN- (5 x 10(-5) to 5 x 10(-3) M) produced rises in [Ca2+](i) in a concentration-dependent manner. Preincubation of these cells with low [Mg2+](o) (0 or 0.3 mM, the lowest physiological range) for 24 h significantly potentiated increments in [Ca2+](i) induced by SCN-. These rises in [Ca2](i) induced by SCN- were completely inhibited by pretreating the cells with 2.4 mM [Mg2+](o) for 24 h. These results support a hypothesis whereby cigarette smoking or exposure to smoking can induce cardiovascular diseases, at least partly, probably by causing spasm and thicknening of arterial blood vessels as a consequence of large rises in [Ca2+](i) in vascular smooth muscle cells. The chronic presence of or exposure to both thiocyanate and low Mg2+ in the blood of smokers can result in rapid flux of Ca2+ into vascular smooth muscle cells, thus accelerating or initiating atherosclerotic processes in smokers, (C) 1999 Academic Press.

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Documento generato il 29/03/20 alle ore 11:41:30