1. Stimulation of the vagal non-adrenergic inhibitory innervation caused the release of adenosine and inosine into vascular perfusates from the stomachs of guinea-pigs and toads.2. Stimulation of portions of Auerbach's plexus isolated from turkey gizzard caused the release of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP).3. ATP, added to solutions p...

Film receptor autoradiography was used to study the distribution of ml-, (r2-, and @-adrenergic receptors in the occipital lobe of developing rhesus monkeys ranging in age from the 65th embryonic day (E65) to adulthood (5 years of age). The study shows that each adrenergic receptor subtype has a unique distribution in the cortical plate and transient embryonic zones of the developing cerebral w...

The adrenergic innervation of the canine kidney was studied with the fluorescence histochemical method of Falck and Hillarp in conjunction with chemical assays for catecholamines in specific portions of the kidney. Adrenergic nerve fibers were seen traveling along the interlobar, arcuate, and interlobular arteries and along the afferent arterioles. The vasa recta of the outer medulla also recei...

RATIONALE In heart failure, myofilament proteins display abnormal phosphorylation, which contributes to contractile dysfunction. The mechanisms underlying the dysregulation of protein phosphorylation on myofilaments is not clear. OBJECTIVE This study aims to understand the mechanisms underlying altered phosphorylation of myofilament proteins in heart failure. METHODS AND RESULTS We generate...

,6-Adrenergic receptors from basal membranes of human placenta were purified from digitonin extracts by sequential rounds of affinity chromatography, hydrophobic chromatography, ion-exchange chromatography and steric-exclusion h.p.l.c. Basal membranes display both j%and fl2-adrenergic receptors, in the ratio 65:35. Affinity chromatography, hydrophobic chromatography on heptylamine-Sepharose and...

Studies were performed in healthy volunteers 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 beta-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinep...

Attenuation of sympathetic vasoconstriction (sympatholysis) in working muscles during dynamic exercise is controversial. A potential mechanism is a reduction in alpha-adrenergic-receptor responsiveness. The purpose of this study was to examine alpha(1)- and alpha(2)-adrenergic-receptor-mediated vasoconstriction in resting and exercising skeletal muscle using intra-arterial infusions of selectiv...

OBJECTIVE Increases in adrenergic activity are associated with stress, anxiety, and other psychiatric, neurological, and medical disorders. To improve understanding of normal CNS adrenergic function, CBF responses to adrenergic stimulation were determined. METHODS Using PET, the CBF changes after intravenous yohimbine, an alpha2-adrenoreceptor antagonist that produces adrenergic activation, w...

α1-Adrenergic stimulation increases blood vessel tone in mammals. This process involves a number of intracellular signaling pathways that include signaling via phospholipase C, diacylglycerol (DAG), and protein kinase C. So far, it is not certain whether signaling via phospholipase D (PLD) and PLD-derived DAG is involved in this process. We asked whether PLD participates in the α1-adrenergic-me...

Myocardial ischemia elicits an enhanced responsivity to alpha 1-adrenergic stimulation and a reversible increase in alpha 1-adrenergic receptor number. In adult cardiac myocytes, alpha 1-adrenergic receptor number increases two- to threefold after 10 min of hypoxia, an increase similar to that seen during ischemia in vivo. To determine whether this increase in alpha 1-adrenergic receptor number...