Effect of TMB-8 on alpha-adrenoceptor agonist and KC1 induced-contractions in isolated rabbit aorta.
1. TMB-8 (10(-6) M-10(-4) M) depresses the contractile effect of the selective alpha 1-adrenoceptor agonists methoxamine and phenylephrine in the isolated rabbit aorta. 2. TMB-8 also depresses contractions evoked by 80 mM KCl in this tissue when used at similar concentrations. 3. The calcium antagonist nifedipine potentiates the inhibitory effect of TMB-8 on the alpha 1-contractions. 4. In preparations mounted in Ca-free solution containing 0.5 mM EGTA, 10(-4) M TMB-8 markedly depressed the contractions caused by both alpha 1-adrenoceptor agonists. 5. The Ca2+ agonist BAY K 8644 (10(-6) M) partially prevented the inhibitory effect of TMB-8 on 80 mM KCl contractions.
Aleixandre
M A
MA
Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
King
A P
AP
Puerro
M
M
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008729:Methoxamine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010656:Phenylephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011189:Potassium Chloride / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011817:Rabbits; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D011189:Potassium Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D008729:Methoxamine