In order to elucidate the mode of action of beta-adrenoreceptor antagonists in essential tremor, the efficacy of chronic oral administration of metoprolol, atenolol and sotalol was compared in a randomised, double-blind placebo controlled trial in twenty-four patients. Only sotalol proved superior to placebo on both subjective and "objective" assessments. Metoprolol and sotalol produced compara...

Two subtypes of beta-adrenoceptors, beta 1 and beta 2, mediate cardiac catecholamine effects. These two types differ qualitatively, e.g., regarding G protein coupling and calcium channel stimulation. Transgenic mice overexpressing human beta 2-adrenoceptors survive high-expression levels, unlike mice overexpressing beta 1-adrenoceptors. We examined the role of inhibitory Gi proteins, known to b...

Convertino, Victor A. Evidence for altered -adrenoreceptor responsiveness after a single bout of maximal exercise. J Appl Physiol 95: 192–198, 2003. First published April 4, 2003; 10.1152/japplphysiol.00123.2003.—We studied hemodynamic responses to and -receptor agonists in eight men to test the hypothesis that adrenoreceptor responsiveness is altered within 24 h of the performance of maximal e...

Sato et al. (1) showed that b2-adrenoreceptor–mediated phosphorylation of mammalian target of rapamycin complex 2 (mTORC2) in skeletal muscles increased GLUT4 translocation to the plasma membrane and thus increased cellular glucose uptake. In diabetes and obesity, an upregulated G-protein–coupled receptor kinase, which inhibits G-protein–coupled receptors, has been reported to contribute to ins...

We measured a2-adrenoreceptor density as well as affinity for and sensitivity to agonist on intact platelets of normotensive and hypertensive subjects before and after physiological increases in plasma catecholamines. In normotensives, posture-induced rises in plasma catecholamines correlated with reduced C2-adrenoreceptor agonist affinity and fewer high affinity state receptors. Platelet aggre...

In order to study the mode of action of beta-adrenoreceptor antagonists in essential tremor the efficacy of single oral doses of 2, 4 and 10 mg LI 32-468, a peripherally acting, selective beta-2 adrenoreceptor antagonist, was compared with a single oral dose of 120 mg propranolol in a randomised, double blind, placebo controlled trial. Both the lowest dose of LI and propranolol were shown to be...

This study tested whether activation of adrenoreceptors in chondrocytes has roles in degenerative remodelling of temporomandibular joint (TMJ) and to determine associated mechanisms. Unilateral anterior crossbite (UAC) was established to induce TMJ degeneration in rats. Saline vehicle, α2- and β-adrenoreceptor antagonists or agonists were injected locally into the TMJ area of UAC rats. Cartilag...

Subcutaneous administration of the alpha 2-adrenoreceptor antagonists, yohimbine and tolazoline, at doses up to 1000 micrograms/kg, had no effect on water intake of female rats. However, when these compounds were administered SC in combination with either the beta-adrenoreceptor agonist, isoproterenol (10 to 25 micrograms/kg, SC), or with angiotensin II (200 micrograms/kg, SC), water intake was...

The damaging effects of excessive glutamate receptor activation have been highlighted recently during injury in developing central white matter. We have examined the effects of acute exposure to four other neurotransmitters that have known actions on white matter. Eighty minutes of Glycine or GABA-A receptor activation produced a significant fall in the compound action potential recorded from i...

We studied hemodynamic responses to alpha- and beta-receptor agonists in eight healthy men before and after 14 days of 6 degrees head-down tilt (HDT) to test the hypothesis that increased adrenoreceptor responsiveness is induced by prolonged exposure to simulated microgravity. Steady-state infusions of isoproterenol (Iso) at rates of 0.005, 0.01, and 0.02 microgram.kg-1.min-1 were used to asses...