β-Adrenergic receptor blockers (β-blockers) are commonly used to treat heart failure, but the biologic mechanisms governing their efficacy are still poorly understood. The complexity of β-adrenergic signaling coupled with the influence of receptor polymorphisms makes it difficult to intuit the effect of β-blockers on cardiac physiology. While some studies indicate that β-blockers are efficaciou...

To identify a physiological role for renal alpha 2 adrenergic receptors, renal vascular and tubular responses to administration of graded frequencies of renal nerve stimulation or graded doses of adrenergic agonists were determined in anesthetized spontaneously hypertensive, Wistar-Kyoto, and Sprague-Dawley rats. Renal vasoconstrictor responses to renal nerve stimulation and alpha 1-adrenergic ...

b-Adrenergic receptor blockers (b-blockers) are commonly used to treat heart failure, but the biologic mechanisms governing their efficacy are still poorly understood. The complexity ofb-adrenergic signaling coupled with the influence of receptor polymorphisms makes it difficult to intuit the effect of b-blockers on cardiac physiology. While some studies indicate that b-blockers are efficacious...

The sympathetic nervous system plays an important role in the regulation of blood pressure. There is increasing evidence for positive and negative interactions between dopamine and adrenergic receptors; the activation of the alpha-adrenergic receptor induces vasoconstriction, whereas the activation of dopamine receptor induces vasorelaxation. We hypothesize that the D1-like receptor and/or D3 r...

Aims: Polymorphisms of the β-adrenergic receptor, the frequency of which may differ in ethnic groups, alters β-receptor function. The aim of this study was to elucidate the frequency of β1 and β2-adrenergic receptor polymorphisms in healthy Greeks and to compare with those of Caucasian European (Euro) and African American (AA) origin. Methods: Ninetynine individuals with a median age of 63 with...

We have used two different cultured cell lines—S49 lymphoma cells and BC3H-1 muscle cells— to examine the regulation of /3-adrenergic receptors by receptor antagonists. Rather than an increase ("up-regulation") of receptor number that such antagonists often produce, we found that certain /3-blockers elicit a decrease ("down-regulation") of beta-adrenergic receptors. Alprenolol and propranolol, ...

We tested the hypothesis that the human 1-adrenergic receptor displays constitutive activity and that -adrenergic antagonists differ in their ability to modulate this constitutive activity. Transfection of the cDNAs of the human 1and 2-adrenergic receptors into COS-7 cells caused increases in basal cAMP that were proportional to the receptor levels, thus demonstrating constitutive activity for ...

Tocolytic therapy with beta-adrenergic receptor agonists is a standard regimen to prevent preterm birth. Agonists exposure of beta-adrenergic receptors causes receptor desensitization in other organs, and this may limit the therapeutic value of beta-adrenergic receptor agonists. To study the effects of prolonged beta-adrenergic agonist treatment in human myometrium, we obtained biopsies during ...

AGAP2 [Arf (ADP-ribosylation factor) GAP (GTPase-activating protein) with GTP-binding-protein-like, ankyrin repeat and PH (pleckstrin homology) domains] is a multidomain Arf GAP that was shown to promote the fast recycling of transferrin receptors. In the present study we tested the hypothesis that AGAP2 regulates the trafficking of β2-adrenergic receptors. We found that AGAP2 formed a complex ...