In:
Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 79, No. 5 ( 1989-05), p. 1118-1124
Abstract:
To study the effects of magnesium (Mg2+) on human coronary arteries and to compare those effects with those of diltiazem and nitroglycerin, we measured the tension of ring segments from isolated human coronary arteries obtained at autopsy within 5 hours after death. Precontracted segments with 3 x 10(-6) M prostaglandin F2 alpha were studied after adding cumulative concentrations of these agents (1.0-8.0 mM, 10(-9)-10(-5) M, and 10(-10)-10(-6) M, respectively). Mg2+ significantly inhibited the tonic contraction compared with the time-matched controls at 1.0 and 2.0 mM (48.7 +/- 5.6% vs. 88.6 +/- 2.2%, p less than 0.01, 36.2 +/- 6.1% vs. 78.9 +/- 3.0%, p less than 0.01, respectively). 1.0 and 2.0 mM Mg2+ did not suppress, but actually increased, the amplitude of periodic contraction, but 8.0 mM Mg2+ reduced the amplitude compared with the controls (6.6 +/- 5.2% vs. 73.3 +/- 10.7%, p less than 0.01). Diltiazem at a concentration of 10(-5) M moderately inhibited the tonic contraction, and reduced the amplitude of periodic contraction almost completely. Nitroglycerin reduced the tonic contraction almost completely at a concentration of 10(-6) M but did not reduce the amplitude of periodic contraction at any concentration. We conclude that 1.0 and 2.0 mM Mg2+ inhibits the tonic contraction and that 8.0 mM Mg2+ inhibits the periodic as well as the tonic contraction of isolated human coronary arteries. Diltiazem inhibits the periodic contraction, whereas nitroglycerin suppresses tonic contraction without affecting the periodic contraction.
Type of Medium:
Online Resource
ISSN:
0009-7322
,
1524-4539
DOI:
10.1161/01.CIR.79.5.1118
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
1989
detail.hit.zdb_id:
1466401-X
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