Calcium and contractile responses to ouabain and potassium-free solution in aortae from spontaneously hypertensive rats

Fred S. Lamb, Robert S. Moreland, R Clinton Webb

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

This study examines the role of calcium in contractions induced by Na+, K+ ATPase inhibition in blood vessels from spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY). Helical strips of aortae from SHR contract more rapidly in response to ouabain or potassium-free conditions than those from WKY rats. Dose-response curves to calcium in SHR aortae treated with 10-3 mol/l ouabain were shifted to the left of those in WKY. Treatment with 10-3 mol/l EGTA shifted dose-response curves to calcium in ouabain-treated strips to the left in both strains. The magnitude of the leftward shift induced by EGTA was greater in WKY aortic strips than in those from SHR. Similarly, treatment with EGTA increased the rate of contractile responses to potassium-free solution in WKY aortae to a greater extent than in SHR aortae. Verapamil (10-6 mol/l) depressed contractions induced by ouabain and potassium-free solution and abolished the differences between SHR and WKY aortae in terms of contraction rate. Calcium-free conditions completely blocked contractions caused by sodium pump inhibition. These results suggest that the difference in responsiveness to sodium pump inhibition in SHR and WKY rats results from an alteration in calcium entry through verapamil-sensitive calcium channels.

Original languageEnglish (US)
Pages (from-to)821-828
Number of pages8
JournalJournal of hypertension
Volume6
Issue number10
StatePublished - Jan 1 1988

Fingerprint

Inbred WKY Rats
Inbred SHR Rats
Ouabain
Aorta
Potassium
Calcium
Egtazic Acid
Sodium-Potassium-Exchanging ATPase
Verapamil
Calcium Channels
Contracts
Blood Vessels

Keywords

  • EGTA
  • Electrogenic sodium pump
  • Vascular smooth muscle
  • Verapamil
  • Wistar-Kyoto rats

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Calcium and contractile responses to ouabain and potassium-free solution in aortae from spontaneously hypertensive rats. / Lamb, Fred S.; Moreland, Robert S.; Webb, R Clinton.

In: Journal of hypertension, Vol. 6, No. 10, 01.01.1988, p. 821-828.

Research output: Contribution to journalArticle

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