A comparative study of potassium-induced relaxation in vascular smooth muscle of tiger salamanders and rats.

G. M. Malvin, R. C. Webb

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Abstract

This study compares potassium-induced relaxation in vascular tissue of an amphibian (Ambystoma tigrinum) and a mammal (rat). Aortas (salamanders) and tail arteries (rats) were cut into helical strips for isometric force recording. After norepinephrine-induced contraction in potassium-free solution, arteries relaxed in response to added potassium (1-20 mmol/l). Potassium-induced relaxation was greater in rat tail arteries than in salamander aortas. Half-maximal relaxation occurred at a potassium concentration of ~3 mmol/l in both species. Ouabain inhibited potassium-induced relaxation; salamanders were more sensitive to the glycoside than rats. Potassium-induced relaxation decreased as the temperature of the bathing medium was lowered; half-maximal inhibition occurred at 19 and 29°C for salamander aortas and rat tail arteries, respectively. Potassium-induced relaxation also varied with the interval in potassium-free solution, the hydrogen ion concentration (rats only), and the magnitude of norepinephrine-induced contraction. It appears that the cellular mechanism causing potassium-induced relaxation is similar in blood vessels of salamanders and rats. The observations are consistent with the hypothesis that stimulated electrogenic sodium transport produces membrane hyperpolarization and relaxation in vascular smooth muscle.

Original languageEnglish (US)
JournalThe American journal of physiology
Volume247
Issue number1 Pt 2
StatePublished - Jul 1 1984

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Ambystoma
Urodela
Vascular Smooth Muscle
Tail
Potassium
Arteries
Aorta
Blood Vessels
Norepinephrine
Amphibians
Ouabain
Glycosides
Mammals

ASJC Scopus subject areas

  • Physiology

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A comparative study of potassium-induced relaxation in vascular smooth muscle of tiger salamanders and rats. / Malvin, G. M.; Webb, R. C.

In: The American journal of physiology, Vol. 247, No. 1 Pt 2, 01.07.1984.

Research output: Contribution to journalArticle

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