To determine the site and possible mechanism of action of adrenergic agents in regulating intraocular pressure, experiments were undertaken to identify, localize, and characterize beta-adrenergic receptors associated with adenylate cyclase in various ocular tissues involved in secretion and reabsorption of aqueous humor. The ciliary process epithelium was found to be enriched in an adenylate cy...

Signals mediated by G-protein-linked receptors display agonist-induced attenuation and recovery involving both protein kinases and phosphatases. The role of protein kinases and phosphatases in agonist-induced attenuation and recovery of beta-adrenergic receptors was explored by two complementary approaches, antisense RNA suppression and co-immunoprecipitation of target elements. Protein phospha...

We describe the cloning and functional expression of a cDNA encoding a novel G protein-coupled receptor, which was isolated from the central nervous system of the pond snail Lymnaea stagnalis. The amino acid sequence predicted by this cDNA shows highest similarity with the sequence of the Locusta tyramine receptor, the Drosophila tyramine/octopamine receptor, and the mammalian alpha-adrenergic ...

The pharmacodynamic activities of two beta adrenergic antagonists, propranolol and practolol, were compared in eight hypertensive patients. The activity of each antagonist was established in relation to its blood concentration at maximal and submaximal adrenergic blockade defined by inhibition of exercise tachycardia. Maximal inhibition of exercise tachycardia was comparable with both drugs and...

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...

Circadian rhythms are daily cycles that control our sleep-wake patterns, hormone release, and body temperature, and are found in virtually all life forms. Because our internal clock runs just over 24 hours, our bodies set it to match day length using environmental cues such as light. Information about light levels travels from the eyes to a brain structure called the pineal gland, which adjusts...

The role of adrenergic agents in augmenting proximal tubular salt and water flux, was studied in a preparation of freshly isolated rabbit renal proximal tubular cells in suspension. Norepinephrine (NE, 10(-5) M) increased sodium influx (JNa) 60 +/- 5% above control value. The alpha adrenergic antagonist, phentolamine (10(-5) M), inhibited the NE-induced enhanced JNa by 90 +/- 2%, while the beta...

The alpha 2 and beta 2 adrenergic receptors, both of which are activated by epinephrine, but which can be differentiated by selective drugs, have opposite effects (inhibitory and stimulatory) on the adenylyl cyclase system. The two receptors are homologous with each other, rhodopsin, and other receptors coupled to guanine nucleotide regulatory proteins and they contain seven hydrophobic domains...

The highly specific a -adrenergic agonist, dexmedetomidine, has hypnotic-sedative, anesthetic-sparing and analgesic effects, and it 2 protects neurons against ischemia. The a -adrenergic agonist, phenylephrine, does not share dexmedetomidine’s pharmacological 1 21 21 properties, although both dexmedetomidine and phenylephrine increase free cytosolic Ca ([Ca ] ) in astrocytes, and most of i dexm...