Sensitivity and adrenoceptor affinity in the mesenteric artery of the deoxycorticosterone acetate hypertensive rat

P. A. Perry, R. C. Webb

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

This study examines vascular reactivity to α-adrenoceptor agonists in mineralocorticoid (deoxycorticosterone acetate (DOCA-salt)) hypertensive and normotensive rats. The rats were anesthetized and the mesenteric artery was excised and cut helically into strips that were mounted in a muscle bath for the measurement of isometric force development. Addition of norepinephrine, epinephrine, phenylephrine, methoxamine, or clonidine to the bath contractions in all arteries. Arteries from hypertensive rats were more sensitive (lower ED50 values) to each of the agonists than arteries from normotensive rats. α-Adrenoceptor affinity for phentolamine (Schild analysis; norepinephrine as the agonist) in hypertensive arteries was not significantly different from that in normotensive arteries. Maximal force generation to clonidine was greater in hypertensive arteries than in normotensive arteries. These results demonstrate an augmented vascular sensitivity to several α-adrenoceptor agonists in DOCA hypertensive rats. This change in sensitivity is independent of a change in affinity for the adrenoceptor antagonist, phentolamine. It may be that a change in receptor number or an alteration in a post-receptor activation event accounts for this enhanced adrenoceptor responsiveness in mineralocorticoid hypertension.

Original languageEnglish (US)
Pages (from-to)1095-1099
Number of pages5
JournalCanadian Journal of Physiology and Pharmacology
Volume66
Issue number8
DOIs
StatePublished - Jan 1 1988
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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