[Interactions between alpha 1, alpha 2 and beta receptors in the blood pressure effects of adrenaline and noradrenaline in the dog].
In anaesthetized dog, the adrenaline induced hypertension is reversed by both alpha 1- and alpha 2-adrenoceptor blocking agents such as AR-C 239 and yohimbine. After alpha 1 or alpha 2 and beta-blockade, adrenaline induced again an increase in blood pressure. This hypertensive effect was suppressed by an alpha 2-adrenoceptor blocking agent when an alpha 1-adrenoceptor blocking was responsible for the reversal of adrenaline-induced hypertension, and conversely. After beta-blockade, both alpha 1- and alpha 2-adrenoceptor blockade is necessary for suppressing any tensional effect of adrenaline. On the other hand, alpha 1- and alpha 2-adrenoceptor blockade are both required to prevent beta-blockade from restoring adrenaline hypertensive effect. Similar effects were observed wih noradrenaline. In fact, only a significant decrease of the noradrenaline-induced hypertension was observed after each alpha-blocker. Both alpha 1- and alpha 2-adrenoceptor blocking agent also significantly inhibited the hypertension induced by noradrenaline. For completely suppressing the effect of noradrenaline on blood pressure, a combination of alpha 1, alpha 2 and beta-blockade is necessary. These results are compatible with a stimulation by adrenaline and noradrenaline of both alpha 1- and alpha 2-adrenoceptors to produce increase in blood pressure.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004285:Dogs; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D015016:Yohimbine / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D015016:Yohimbine; D011433:Propranolol; D009638:Norepinephrine; D004837:Epinephrine
Interactions entre les récepteurs alpha 1, alpha 2 et beta dans les effets tensionnels de l'adrénaline et de la noradrénaline chez le chien.