MECHANISM OF CONTRACTION OF RAT AORTA TO VARIOUS AGONISTS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 220  (2) , 180-188
Abstract
To elucidate the mechanism of contraction of the smooth muscle of the rat aorta, its response to norepinephrine (NE), 5-hydroxytryptamine (5-HT) and KCl was determined before and after pretreatment with reserpine and .beta.-diethylaminoethyl-2-2-diphenylpropyl acetate (SKF 525-A). Unlike rabbit aorta, contraction of the rat aorta induced by NE was inhibited by SKF 525-A. After the induction of maximal contraction, SKF 525-A induced a graded rapid relaxation after KCl, less so after 5-HT and least after NE. Pretreatment with reserpine failed to induced supersensitivity to NE. After incubation in a Ca2+-free or Na+ and Ca2+-free Krebs solution, rat aorta failed to contract even on the addition of Ca2+ or NE.