1. Field electrical stimulation elicited an increase of the tritium efflux over the basal level from cat cerebral arteries previously incubated with (+/-) [3H]noradrenaline ([3H]NA). 2. This efflux was: (a) reduced by clonidine, NA or B-HT 920; (b) unaffected by methoxamine, prazosin and yohimbine (10(-6) M); (c) reduced by yohimbine (5 x 10(-6) M), and (d) increased by phentolamine. 3. The effect of clonidine was blocked by yohimbine. 4. The daily treatment with the neuronal uptake blockers desipramine (10 mg/kg, i.p.) or cocaine (10 mg/kg, i.p.) [during 12 days], antagonized the inhibitory action of clonidine totally or partially, respectively. 5. These results suggest: (1) the existence of presynaptic alpha 2-adrenoceptors in these arteries, which modulate the NA release, and (2) that chronic treatment with desipramine or cocaine induces a subsensitivity of these alpha 2-receptors, which facilitates the NA release.
Cerebral blood flow and vascular reactivity after removal of the superior cervical sympathetic ganglion in the goat
Neurogenic dilator and constrictor responses of pial arteries in vitro. Differences between dogs and sheep
Pre- and postsynaptic effects of yohimbine stereoisomers on noradrenergic transmission in the pulmonary artery of the rabbit
Noradrenaline release in the human pulmonary artery is modulated by presynaptic alpha 2-adrenoceptors
Reduced peripheral presynaptic adrenoceptor sensitivity following chronic antidepressant treatment in rats.
Activation and desensitization of presynaptic alpha 2-adrenoceptors after inhibition of neuronal uptake by antidepressant drugs in the rat vas deferens
Responsiveness of isolated cerebral and peripheral arteries to serotonin, norepinephrine, and transmural electrical stimulation
Presynaptic activity of the imidazolidine derivative ST 587, a highly selective alpha 1-adrenoceptor agonist
Experimental conditions required for the enhancement by alpha-adrenoceptor antagonists of noradrenaline release in the rabbit ear artery
An investigation of presynaptic alpha-adrenoceptor subtypes in the pithed rat heart and in the rat isolated vas deferens
Transmitter release modulated by alpha-adrenoceptor antagonists in the rabbit mesenteric artery: a comparison between noradrenaline outflow and electrical activity
Pharmacological properties of prejunctional alpha-adrenoceptors in isolated feline middle cerebral arteries; comparison with the postjunctional alpha-adrenoceptors
Binding of an imidazolidine (clonidine), an oxazoloazepin (B-HT 933) and a thiazoloazepin (B-HT 920) to rat brain alpha-adrenoceptors and relation to cardiovascular effects
Investigation into different types of post- and presynaptic alpha-adrenoceptors at cardiovascular sites in rats
alpha 2-Adrenoreceptors in rat brain are decreased after long-term tricyclic antidepressant drug treatment
Regulation of noradrenaline release in human cerebral arteries via presynaptic alpha 2-adrenoceptors.
Involvement of alpha 2-adrenoceptors and protein kinase C on nicotine-induced facilitation of noradrenaline release in bovine cerebral arteries
Effect of neuropeptide Y on adrenergic and non-adrenergic, non-cholinergic responses in the rat anococcygeus muscle.
Characterization of the subtype of presynaptic alpha 2-adrenoceptors modulating noradrenaline release in cat and bovine cerebral arteries
Evidence for alterations in alpha2-adrenergic receptor sensitivity in rats exposed to repeated cocaine administration
Adrenergic Receptors: Trafficking
Adrenergic receptor trafficking is an active physiological process where adrenergic receptors are relocated from one region of the cell to another or from one type of cell to another. Discover the latest research on adrenergic receptor trafficking here.