A comparison of the vasorelaxant effects of enoximone and dibutyryl cyclic AMP measured in rat aortic rings.
After preconstriction of rat aortic rings by norepinephrine (NE; 5*10(-5) M) or by high potassium (K+; 3*10(-2) M), a dose-dependent relaxation was induced by enoximone (E) in a range of 1*10(-5) M - 2*10(-4) M. The time to 50% dilatation was constant in that range, with mean values of 2.2 (NE) and 3.8 (K+) minutes. Also dibutyryl cyclic AMP (Db cAMP) in a range of 6*10(-5) M - 2*10(-3) M produced a dose-dependent relaxation. Comparison of the concentrations of E and Db cAMP producing equal extent of vasorelaxation demonstrated that inhibition of phosphodiesterase with E proved to be more effective than adding Db cAMP in equimolar dose.
Schweitzer
D H
DH
Department of Internal Medicine, University Hospital Leiden, The Netherlands.
Koek
G H
GH
Meinders
A E
AE
van der Laarse
A
A
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D003994:Bucladesine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D017335:Enoximone; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011914:Rats, Inbred BN; D014664:Vasodilation / Q000187:drug effects*
D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D003994:Bucladesine; D017335:Enoximone; D011188:Potassium; D009638:Norepinephrine