The isolated internal anal sphincter from cats shows a myogenic spontaneous rhythmic activity. Basal tension and frequency of contraction waves from internal anal sphincter strips are inhibited by muscarinic and beta-adrenergic receptors and excited by alpha-adrenergic receptors. Isoprenaline in high doses had an alpha-adrenoceptor-stimulating activity in strips from the internal sphincter. The...

Both a(vasoconstrictor) and (3(vasodilator) receptor activity was demonstrated in the coronary arteries of the unanesthetized dog independent of adrenergic receptors in the myocardium. In the y3-receptor blocked animal, a-adrenergic receptor activity was demonstrated after intravenous and intracoronary injections of epinephrine and norepinephrine by the occurrence of coronary vasoconstriction w...

Activation of human alpha1A-adrenergic receptors in PC12 cells causes many second messenger, mitogenic, and transcriptional responses. We examined the role of G protein activation in these responses by uncoupling the receptor through deletion of the first three amino acids from the third intracellular loop (Delta208-210). Expression levels of retrovirus-transfected wild-type and Delta(208-210) ...

BACKGROUND Mammalian spermatozoa have been shown to have beta(1,2,3)- and alpha(2A)-adrenergic receptors, the former functioning only in uncapacitated spermatozoa and the latter only in capacitated cells. Cathine, an amphetamine-related metabolite of a compound found in Catha edulis leaves, accelerates capacitation and inhibits spontaneous acrosome loss by regulating cAMP production. This study...

Introduction : The present study is aimed at investigation of the mechanism action a new 3-substituted thietane-1,1-dioxide derivative (N-199/1) exhibiting antidepressant properties, in several tests neuropharmacological interaction. Materials and methods To N-199/1, its effect on 5-hydroxytryptophan (5-HTP)-induced head-twitch response (50 mg/kg 300 mg/kg), haloperidol-induced catalepsy (1 are...

Stress can trigger the relapse of drug use in recovering cocaine addicts and reinstatement in rodent models through mechanisms that may involve norepinephrine release and β-adrenergic receptor activation. The present study examined the role of β-adrenergic receptor subtypes in the stressor-induced reinstatement of extinguished cocaine-induced (15 mg/kg i.p.) conditioned place preference in mice...

The genetically, seasonally, and diet-induced obese, glucose-intolerant states in rodents, including ob/ob mice, have each been associated with elevated hypothalamic levels of norepinephrine (NE). With the use of quantitative autoradiography on brain slices of 6-wk-old obese (ob/ob) and lean mice, the adrenergic receptor populations in several hypothalamic nuclei were examined. The binding of [...

The nonselective alpha-adrenergic antagonist, phenoxybenzamine, has been used in the treatment of neuropathic pain syndromes, specifically, complex regional pain syndrome (CRPS) types I and II. This agent has also previously been used in intravenous regional peripheral blocks for treatment of CRPS I; however, an intravenous preparation of phenoxybenzamine is not currently available in the U.S.A...

Discontinuous density sucrose gradient centrifugation was used to isolate membrane vesicles from the left ventricle of three normal subjects (one prospective organ donor and two traffic victims whose hearts were obtained 1 hour after death) and nine patients undergoing cardiac transplantation as a consequence of idiopathic dilated cardiomyopathy. Sarcolemma-enriched subcellular fractions, detec...

Luteal cells are known to possess receptors for LH/hCG and receptors of the beta-adrenergic type. Interactions of specific agonists with either receptor lead to the activation of adenylate cyclase and subsequently to an increase of cAMP. Since in the human there is also evidence for the presence of alpha-adrenergic receptors, we have investigated whether activation of these receptors is linked ...