IMR Press / FBL / Volume 2 / Issue 1 / DOI: 10.2741/A156

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article

Magnesium protects against cocaine-induced hemorrhagic stroke in a rat model: a 31P-NMR in-vivo study

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1 Department of Physiology, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
2 Departments of Medicine, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
3 The Center for Cardiovascular and Muscle Research , State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
4 Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
Front. Biosci. (Landmark Ed) 1997, 2(1), 9–12; https://doi.org/10.2741/A156
Published: 15 May 1997
Abstract

In-vivo 31P-nuclear magnetic resonance (NMR) studies were undertaken with anesthetized rats to determine: a. whether systemic administration of MgCl2 could protect animals against cocaine-induced hemorrhagic stroke, and b. whether a relationship exists between basal levels of brain intracellular free magnesium ions ([Mg2+]i), phosphometabolites, and stroke risk. Repeat 31P-NMR spectra were obtained at various intervals of time (3-120 min, or up until death) after administration of cocaine (5 + 30 mg/kg). Ion selective electrodes were used to measure plasma Mg2+, K+, Na+ and Ca2+. Forty percent of animals died in the absence of Mg2+ infusion following high dosage of cocaine. Only 13% died with cocaine following Mg2+ infusion (p <0.005). In the Mg2+-protected animals, neither brain [Mg2+]i,intracellular pH (pHi), [phosphocreatine-PCr]/[ATP], nor brain [inorganic phosphate-Pi]/[ATP] fell when toxic and lethal doses of cocaine were given. Low basal brain [Mg2+]i (275 +/- 24 vs. 466 +/- 35 microM, p <0.01) and low basal brain [PCr] (3.36 +/- 0.35 vs. 4.26 +/- 0.24 mM, p <0.01) were found to be associated with a 3-fold increased incidence of stroke. A positive correlation (r = 0.31, p <0.03) between brain [Mg2+]1 and [PCr]/[ATP] was found. It is possible that both brain [Mg2+]i and [PCr] may be useful as important predictors of susceptibility to cocaine-induced hemorrhagic stroke.

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