RT Journal Article
SR Electronic
T1 CORTICOSTEROID ANTAGONISM OF THE POSITIVE INOTROPIC EFFECT OF OUABAIN
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 294
OP 299
VO 151
IS 2
A1 Allan M. Lefer
YR 1966
UL http://jpet.aspetjournals.org/content/151/2/294.abstract
AB A variety of corticosteroids were evaluated as ouabain antagonists in the isolated cat papillary muscle preparation. Aldosterone, 2α-methyl 9α-fluorocortisol, deoxycorticosterone, 9α-fluorocortisol, dexamethasone and corticosterone antagonized the positive inotropic effect of ouabain at 37°C in low-calcium buffer. Cortisol, Reichstein’s Substance S, 11-dehydrocorticosterone, prednisolone and 6α-methylprednisolone did not antagonize ouabain. At concentrations much higher than those of other effective corticosteroids, progesterone also antagonized ouabain. However, this antagonism occurred after a large negative inotropic effect and probably represents a toxic response. At 27°C aldosterone failed to antagonize ouabain, but at this lower temperature aldosterone exerted a much greater positive inotropic effect than at 37°C. A dual receptor mechanism hypothesis is offered to explain tentatively both the inotropic and anti-ouabain effects of aldosterone. The Williams & Wilkins Comapny