Dogfish pressor response to potassium blocked by magnesium and phentolamine

In vivo infusion of MgCl2 blocks the dogfish pressor response to K+. This action of Mg2+ was contrasted to phentolamine in in vivo and in vitro experiments. Mg2+ blocks the spontaneous release of catecholamines from dogfish chromaffin tissue but does not alter the norepinephrine-induced contraction...

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Bibliographic Details
Published inThe American journal of physiology Vol. 242; no. 3; pp. R185 - R188
Main Authors Carroll, R.G, Opdyke, D.F, Keller, N.E
Format Journal Article
LanguageEnglish
Published United States 01.03.1982
Subjects
Animals
Blood Pressure - drug effects
Catecholamines - pharmacology
Chromaffin System - physiology
Dogfish - physiology
Magnesium - pharmacology
Muscle, Smooth, Vascular - physiology
Phentolamine - pharmacology
Potassium - pharmacology
Sharks - physiology
Squalus acanthias
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Summary:In vivo infusion of MgCl2 blocks the dogfish pressor response to K+. This action of Mg2+ was contrasted to phentolamine in in vivo and in vitro experiments. Mg2+ blocks the spontaneous release of catecholamines from dogfish chromaffin tissue but does not alter the norepinephrine-induced contraction of the isolated dogfish artery. In vivo infusion of Mg2+ causes a significant decrease in resting catecholamine levels and diminishes the catecholamine release caused by K+ challenge. Both Mg2+ and phentolamine block the pressor action of K+, Mg2+ by preventing the K+-induced release of catecholamines and phentolamine by preventing the circulating catecholamines from interacting with alpha-adrenergic receptor sites.
ISSN:0002-9513
2163-5773
DOI:10.1152/ajpregu.1982.242.3.r185