Sensitization of Noradrenaline Responses by Inhibitors of Extraneuronal Uptake in a Coronary Artery Preparation

Abstract

Inhibition of neuronal uptake with cocaine had no significant effect on the dose-response curve to noradrenaline in strips of beef coronary artery. However, responses were enhanced about 3-fold by 173-oestradiol and the haloalkylamine GD-131, two known inhibitors of extraneuronal uptake.The coronary blood vessels of diverse species generally respond to the sympathetic nerve transmitter, noradrenaline, with 3-adrenoceptor mediated relaxation, although under in vivo conditions the intensity of the overall effect may be related to the metabolic state of the heart (Gaal, Kattus, Kolin & Ross, 1966;Parratt, 1967 give a stock concentration of 10 mg/ml. The volume of propylene glycol usually added to the muscle chambers was 0.015 ml and when used alone it had no effect on the basal tone of strips or on their responses to potassium or noradrenaline. Strips were exposed to cocaine (10 g/ml) or to 17.-oestradiol (1O,ug/ml) for 15 min and responses to agonists were then obtained without washout of the muscle chambers.The haloalkylamine compound, GD-131

Inhaled corticosteroids: effects on the airway vasculature in bronchial asthma

“…A similar phenomenon has been reported recently in the rat sciatic nerve [149] and the human bronchial mucosa [29]. Corticosteroids have also been shown to acutely enhance responses to vasoconstrictors in several systemic vascular beds, including radial [150], coronary [151], ophthalmic [152], and bronchial arteries [153]. Furthermore, corticosteroids may acutely (within 60 min) restore vasoconstrictor responses to norepinephrine in patients with medical conditions of impaired production of endogenous corticosteroids [154], and in experimental adrenalectomy [155].…”

The classification of β‐adrenoceptors in isolated ring preparations of canine coronary arteries

“…In fact, potentiation, by ex-traneuronal uptake inhibitors, of responses known to be mediated exclusively by f1-adrenoceptors has not previously been described. Although extraneuronal uptake inhibitors potentiated responses of coronary arteries of sheep to isoprenaline (Brine et al, 1979) and of ox to noradrenaline (Kalsner, 1974;Kalsner et al, 1975), the absence of a minor population of 02-adrenoceptors in the preparations from these two species has not yet been experimentally established. In the present study, responses of the canine left circumflex artery to isoprenaline (mediated exclusively by 131-adrenoceptors, vide supra) were potentiated by corticosterone and by metanephrine.…”

Effects of Uptake Inhibitors on Responses of Sheep Coronary Arteries to Catecholamines and Sympathetic Nerve Stimulation

“…The importance of these inactivation processes in modifying catecholamine responses in coronary arteries has only been studied previously with exogenous amines. There is general agreement that the neuronal uptake inhibitor, cocaine, does not sensitize isolated coronary arteries to noradrenaline (Nishioka, 1971;Kalsner, 1974;De la Lande et al, 1974;. 0007-1188/79/120553-09 $01.00…”