Prolonged exposure of cells or tissues to drugs or hormones such as catecholamines leads to a state of refractoriness to further stimulation by that agent, known as homologous desensitization. In the case of the beta-adrenergic receptor coupled to adenylate cyclase, this process has been shown to be intimately associated with the sequestration of the receptors from the cell surface through a cA...

Beta-adrenergic drugs affect lens epithelial and fiber cells. The regulation and cellular integration of lens beta-adrenergic responses are largely unknown. These studies further characterize beta-adrenergic receptors in lens cells with respect to cyclic adenosine monophosphate (cAMP) production and identification of receptor polypeptides. Stimulation of beta-adrenergic receptors in organ-cultu...

α(1)-Adrenergic receptor subtypes are widely distributed in the central nervous system and are involved in autonomic functions such as micturition. We investigated the presence and the role of supraspinal and/or spinal α(1)-adrenergic receptors in modulating the micturition reflex in conscious female Wistar rats. The expression of α(1)-adrenergic receptor subtypes in rat brain and lumbosacral s...

'H](±)Carazolol, " newly available ^-adrenergic receptor antagonist, has been used to characterize /f-adrenergic receptor subtypes present in membrane vesicles derived from canine ventricular myocardium and canine lung. [H](±)Carazolol binding is saturable, of high affinity, and in displaceable by /J-adi-e.nergic agents in accordance with their known pharmacological potencies. The interaction o...

To elucidate the mechanisms responsible for the increase in alpha 1-adrenergic receptors during ischemia in vivo, we developed a procedure for measuring alpha 1-adrenergic receptors in isolated, calcium-tolerant adult canine myocytes. Specific [3H]prazosin binding was rapid, saturable, reversible, and demonstrated the expected order of potency and stereospecificity for the alpha 1-adrenergic re...

To elucidate the mechanisms responsible for the increase in a,-adrenergic receptors during ischemia in vivo, we developed a procedure for measuring a,-adrenergic receptors in isolated, calcium-tolerant adult canine myocytes. Specific pH]prazosin binding was rapid, saturable, reversible, and demonstrated the expected order of potency and stereospecificity for the a,-adrenergic receptor. Myocytes...

Alpha (alpha)- and beta (beta)-adrenergic receptors in the bovine mammary gland are mainly present in the teat muscles and in the region where large milk ducts reach the cisternal cavities. The aim of the study was to test the hypothesis that the region of the large mammary ducts is the most important location of alpha- and beta-adrenergic receptor stimulation affecting milk ejection and milk r...

cirrhosis is characterized by marked abnormalities in the cardiovascular system. a hyperdynamic splanchnic and systemic circulation is typical of cirrhotic patients and has been observed in all experimental forms of portal hypertension. the hyperdynamic circulation is most likely initiated by arterial vasodilatation, leading to central hypovolemia, sodium retention, and an increased intravascul...

the study was carried out to desensitize spontaneously active isolated chick rectum with salbutamol in log doses starting from 100 nanogram and resensitize with various drugs as a result to revive the desensitized tissue and respond to salbutamol. the tissue response after desensitization to alpha, beta adrenergic and muscarinic acetylcholine receptor antagonists was isotonically recorded for 1...

Abbreviations: A1R: Adenosine A1 Receptor; A2AR: Adenosine A2A Receptor; A2BR: Adenosine A2B Receptor; A3R: Adenosine A3 Receptor; Cpd: Compound; D2R: Dopamine D2 Receptor; Emax: Efficacy; gp: Guinea-pig; GPCR: G-Protein Coupled Receptor; h: Human; H1R: Histamine H1 Receptor; H3R: Histamine H3 Receptor; r: rat; 5-HT1AR: Serotonine 5-HT1A Receptor; βR: β-Adrenergic Receptors; β2R: Adrenergic β2 ...