By measurement of the specific binding of 3H-dihydroalprenolol, the densities of beta-adrenergic receptors on membranes prepared from homogenized corneas and iris--ciliary bodies of rabbits were studied. Sympathetic denervation, as a result of subconjunctival treatment with 6-hydroxydopamine, causes an increase in the density of beta-adrenergic receptors in membranes prepared from the ipsilater...

Molecular cloning of the alpha 2A-adrenergic receptor has shown that this receptor is a member of the gene superfamily of guanine nucleotide-binding protein (G protein)-coupled receptors. The alpha 2A-adrenergic receptor expressed in Chinese hamster ovary (CHO) cells attenuates and potentiates forskolin-stimulated cAMP production through independent signaling pathways. To examine the role of th...

BACKGROUND Autoantibodies against synthetic peptides of beta-adrenergic receptors have been observed in human cardiomyopathy. However, it has never been shown that such antibodies really interact with native human beta-adrenergic receptors, nor has the clinical impact of such an interaction been investigated in larger groups of patients. METHODS AND RESULTS We screened 104 patients with dilat...

FRTL-5 rat thyroid cells grown and maintained in a medium containing 0.05 nM thyrotropin have a 10-fold higher number of alpha 1-adrenergic receptors on their cell surface than FRTL-5 cells maintained in the absence of thyrotropin in their medium. The increased number of alpha 1-adrenergic receptors, measured as increased specific [3H]prazosin binding per microgram of DNA, is not associated wit...

We have used two different cultured cell lines--S49 lymphoma cells and BC3H-1 muscle cells--to examine the regulation of beta-adrenergic receptors by receptor antagonists. Rather than an increase ("up-regulation") of receptor number that such antagonists often produce, we found that certain beta-blockers elicit a decrease ("down-regulation") of beta-adrenergic receptors. Alprenolol and proprano...

The appearance of P-adrenergic receptors and isoproterenol-stimulated adenylate cyclase during differentiation of embryonic quail muscle cells in tissue culture has been examined. P-Adrenergic receptors first appear during the fusion stage of myogenesis. ['"I]]Iodohydroxybenzylpindolol (['2sI]IHYP) was used as the ligand to characterize &adrenergic receptors. In equilibrium binding studies, mat...

Background—Autoantibodies against synthetic peptides of b-adrenergic receptors have been observed in human cardiomyopathy. However, it has never been shown that such antibodies really interact with native human b-adrenergic receptors, nor has the clinical impact of such an interaction been investigated in larger groups of patients. Methods and Results—We screened 104 patients with dilated or is...

Adrenergic receptors for adrenaline and noradrenaline belong to the large multigenic family of receptors coupled to GTP-binding proteins. Three pharmacologic types have been identified: alpha 1-, alpha 2-, and beta-adrenergic receptors. Each of these has three subtypes, characterized by both structural and functional differences. The alpha 2 and beta receptors are coupled negatively and positiv...

BACKGROUND We have recently shown that genetic inactivation of phosphoinositide 3-kinase gamma (PI3Kgamma), the isoform linked to G-protein-coupled receptors, results in increased cardiac contractility with no effect on basal cell size. Signaling via the G-protein-coupled beta-adrenergic receptors has been implicated in cardiac hypertrophy and heart failure, suggesting that PI3Kgamma might play...

The various subtypes of receptors for catecholamines, termed adrenergic receptors, represent excellent models for the study of receptor-mediated transmembrane signalling because of their ubiquity, their coupling to well-defined effector mechanisms, and the clinical importance of drugs which interact with them. In general, the adrenergic receptor systems consist of three components which are cou...