A comparative and regional study of potassium induced relaxation of vascular smooth muscle

R. Clinton Webb, David F. Bohr

Research output: Contribution to journalArticlepeer-review


The current study was undertaken to assess species and regional variations in the relaxation of vascular smooth muscle in response to potassium and in the ouabain sensitivity of this relaxation. The effect of species variation was investigated through the use of tail arteries from rats, dogs, cats, monkeys, and pigs; the effect of regional variation was studied in tail, middle cerebral, femoral, and posterior coronary arteries from baboons. Helical strips from all of these vessels were made to contract with norepinephrine or serotonin in a potassium-free solution. The vessels relaxed when potassium was added back to the solution. Strips of tail artery from rats, dogs, and monkeys showed greater relaxation in response to potassium than did strips from pigs and cats. Helical strips from tail, cerebral, and coronary arteries of the baboon relaxed to a greater degree in response to potassium than did strips from the femoral artery. Ouabain produced a concentration-dependent decrease in the magnitude of potassium relaxation in all vessel types. Half-maximal inhibition occurred at approximately 10-8 to 10-7 M in all arterial strips except those obtained from rat tail artery (5×10-5 M). The inhibition of potassium relaxation by ouabain was fully reversed by 30 min exposure to a ouabain-free solution in only the rat tail artery strips. A component of potassium-induced relaxation in tail artery strips from monkeys and baboons was not inhibited by ouabain. The results show that the magnitude of response, potassium and ouabain sensitivity, and recovery from ouabain treatment of potassium relaxation are species related. The regional bed from which the vascular smooth muscle is derived also determines the magnitude and potassium sensitivity of the relaxation. These parameters of potassium-dependent relaxation may reflect corresponding differences in the electrogenic pumping of sodium and potassium among various animal species and various regional vascular beds.

Original languageEnglish (US)
Pages (from-to)357-363
Number of pages7
JournalJournal of Comparative Physiology □ A
Issue number4
StatePublished - Dec 1980
Externally publishedYes

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Animal Science and Zoology
  • Behavioral Neuroscience


Dive into the research topics of 'A comparative and regional study of potassium induced relaxation of vascular smooth muscle'. Together they form a unique fingerprint.

Cite this