In vitro studies on 6-fluoronoradrenaline at several peripheral sympathetic neuroeffector junctions.
A comparison of the effects of noradrenaline and 6-fluoronoradrenaline has been made at several peripheral sympathetic neuroeffector junctions. In the rat vas deferens preparation in the presence of 1 microM cocaine, 6-fluoronoradrenaline was found to be about 9 times more potent than noradrenaline as an agonist at presynaptic inhibitory alpha 2- adrenoceptors. In the rabbit aorta, 6-fluoronoradrenaline had approximately one tenth of the potency of noradrenaline in stimulating the postsynaptic alpha 1-adrenoceptors. Furthermore 6-fluoronoradrenaline, in contrast to previous reports, appears to be a substrate for the neuronal uptake process since exposure to cocaine potentiated the inhibition of the twitch response of the vas deferens by 6-fluoronoradrenaline. In addition, 6-fluoronoradrenaline increased the spontaneous outflow of radioactivity from rabbit pulmonary artery strips prelabelled with 3H-noradrenaline and this increase was blocked by cocaine (30 microM). These results demonstrate that 6-fluoronoradrenaline is a preferential alpha 2-adrenoceptor agonist which is a substrate for the neuronal uptake process in peripheral sympathetically innervated smooth muscle preparations.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009451:Neuroeffector Junction / Q000187:drug effects*; D009638:Norepinephrine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D014649:Vas Deferens / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; C024884:6-fluoronorepinephrine; D009638:Norepinephrine