Faculty Collaboration Database

Hypomagnesemia inhibits nitric oxide release from coronary endothelium: protective role of magnesium infusion after cardiac operations. Ann Thorac Surg 1998 Apr;65(4):967-72

Date

05/16/1998

Pubmed ID

9564911

DOI

10.1016/s0003-4975(98)00020-4

Scopus ID

2-s2.0-0031898918 (requires institutional sign-in at Scopus site)   104 Citations

Abstract

BACKGROUND: Postoperative hypomagnesemia is common in patients who have undergone cardiac operations and is associated with clinically significant morbidity resulting from atrial and ventricular dysrhythmias. Magnesium supplementation may increase the cardiac index in the early postoperative period.

METHODS: The action of the magnesium cation on coronary vascular reactivity was studied. Segments of canine epicardial coronary artery were suspended in organ chambers to measure isometric force (95% O2/5% CO2, 37 degrees C).

RESULTS: In coronary segments constricted with prostaglandin F2alpha (2 x 10[-6] mol/L), acetylcholine and adenosine diphosphate (10[-9] to 10[-4] mol/L) induced vasodilation in arteries with endothelium (n=10, each group; p < 0.05). Acetylcholine-mediated vasodilation was blocked by NG-monomethyl-L-arginine (10[-4] mol/L) and NG-nitro-L-arginine (10[-4] mol/L), two inhibitors of nitric oxide synthesis from L-arginine (n=10, p < 0.05). The removal of magnesium from the organ chamber solution impaired vasodilation in response to acetylcholine and adenosine diphosphate. However, normal endothelium-dependent vasodilation could be restored by return of magnesium to the bathing solution. Vascular relaxation in response to bradykinin (10[-9] to 10[-6] mol/L), which was found to induce endothelium-dependent vasodilation independent of nitric oxide production, was unaffected by magnesium removal (n=10).

CONCLUSIONS: Hypomagnesemia selectively impaired the release of nitric oxide from the coronary endothelium. Because nitric oxide is a potent endogenous nitro-vasodilator and inhibitor of platelet aggregation and adhesion, hypomagnesemia could promote vasoconstriction and coronary thrombosis in the early postoperative period.

Author List

Pearson PJ, Evora PR, Seccombe JF, Schaff HV

Author

Paul Joseph Pearson MD, PhD Chief, Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acetylcholine
Adenosine Diphosphate
Animals
Arrhythmias, Cardiac
Bradykinin
Cardiac Output
Cardiac Surgical Procedures
Coronary Thrombosis
Coronary Vessels
Dinoprost
Dogs
Endothelium, Vascular
Enzyme Inhibitors
Female
Infusions, Intravenous
Magnesium
Male
Nitric Oxide
Nitric Oxide Synthase
Nitroarginine
Pericardium
Platelet Aggregation Inhibitors
Postoperative Complications
Vasoconstriction
Vasoconstrictor Agents
Vasodilation
Vasodilator Agents
omega-N-Methylarginine