To better understand the nature of interaction of various amines with adrenergic receptors in te human ciliary process, beta-adrenergic-stimulated adenylate cyclase activity was characterized in broken cell preparations of this tissue from donor eyes. Among various agonists, isoproterenol was the most potent activator of enzyme activity (Ka = 3.4 x 10(-7)M), followed in order by epinephrine (Ka...

The molecular nature of mammalian beta-adrenergic receptors in situ was probed using immunoblotting and functional reconstitution techniques. Membrane proteins of cells replete with beta-adrenergic receptors were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the resolved proteins were transferred to nitrocellulose and then probed with anti-receptor antibodies. When...

Vasopressor agents may affect cerebral oxygenation (rScO2) as determined by near-infrared spectroscopy on the forehead. This case series evaluated the effect of calcium chloride vs. α and β-adrenergic receptor agonists on rScO2 in patients (n = 47) undergoing surgery during i.v. anesthesia. Mean arterial pressure (MAP) and cardiac output (CO) were assessed by Model-flow(®) and ephedrine (55 ± 3...

We show that adrenergic agents modulate hematopoietic reconstitution after syngeneic bone marrow transplantation (BMT) in mice. Chemical sympathectomy by 6-hydroxydopamine (6-OHDA) significantly increased the number of peripheral blood leukocytes after syngeneic BMT. The alpha 1-adrenergic antagonist prazosin mimicked and extended the effect of 6-OHDA, with an additional rapid and significant i...

unteers to determine the effects of catecholamines and adrenergic-blocking agents on plasma and urinary levels of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP). Plasma cyclic AMP rose in response to infusions of the P-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinephrine alone or -in combination with the ...

Propranolol is a nonselective beta-adrenergic receptor blocking agent possessing no other autonomic nervous system activity. It specifically competes with beta-adrenergic receptor agonist agents for available receptor sites. When access to beta-receptor sites is blocked by propranolol, the chronotropic, inotropic, and vasodilator responses to beta-adrenergic stimulation are decreased proportion...

A proposed theory for the development of bmmhial asthma suggests the presence of partial or complete blockage of the beta-adrenergic nervous sy~ tem. l~~ Evidence to support this hypothesis stems from observations that individuals with bronchial astbma have increased sensitivity to beta-adrenergic blocking agents, as well as specific pharmacologic, physiologic and biochemical alteration~.~-~ Th...

Although quinidine is known to have antiadrenergic effects in the cardiovascular system, the precise mechanism by which it exerts these effects is not well defined. We asked whether quinidine binds directly to adrenergic receptors. Radioligand-binding assays were used to identify <*i -adrenergic receptors ([H]prazosin-binding sites) on membranes prepared from rat heart and kidney, a2-adrenergic...

Although quinidine is known to have antiadrenergic effects in the cardiovascular system, the precise mechanism by which it exerts these effects is not well defined. We asked whether quinidine binds directly to adrenergic receptors. Radioligand-binding assays were used to identify <*i -adrenergic receptors ([H]prazosin-binding sites) on membranes prepared from rat heart and kidney, a2-adrenergic...

Clonidine is reported to inhibit the az-adrenoceptor mediated pinnal reflex in mice (3). Clonidine produces its effect by acting as an oc2-adrenergic autoreceptor agonist (1). As such, clonidine is also agonist for presynaptic histamine Hz-receptors (8). To test whether the clonidine-induced inhibition of the pinnal reflex is mediated through adrenergic and/or histaminergic system, the interact...