BACKGROUND The effects of acute and repeated treatment with desipramine on the functional response of alpha2-adrenoceptors were tested in adult and 13-day old rats. The functional response measured was hypothermia that was induced by brimonidine, an alpha2-adrenoceptor agonist. The change in the extent of the brimonidine-induced hypothermia following pretreatment with either single or 4 twice-d...

The involvement of supraspinal alpha-adrenergic receptors in tonic pain was assessed in formalin-induced pain in rats. The alpha2 adrenoceptor agonist clonidine, along with yohimbine and prazosin, α2 and α1 receptor antagonists, were introduced intracerebroventrically (icv) and/or systemically in different doses. The data show that 1) clonidine exerts an alpha adrenergic analgesic effect, ...

The insular cortex (IC) has been reported to be involved in central cardiovascular control. In the present study, we investigated the cardiovascular responses evoked by microinjection of noradrenaline into the IC as well as the central and peripheral mechanisms involved in their mediation. Microinjection of noradrenaline into the IC (3, 7, 10, 15, 30 and 45 nmol/100 nL) caused long-lasting dose...

We have studied rats with chronically implanted subarachnoid catheters. Xylazine, an alpha 2 adrenoceptor agonist, was injected intrathecally and nociceptive thresholds measured at two skin sites: the tail and the neck. Intrathecal xylazine (dose range 24.3-389 nmol) produced increases in electrical thresholds for nociception in the tail without any change in the neck; this observation suggeste...

Beta1- and beta2-adrenoceptors in heart muscle cells mediate the catecholamine-induced increase in the force and frequency of cardiac contraction. Recently, in addition, we demonstrated the functional expression of beta3-adrenoceptors in the human heart. Their stimulation, in marked contrast with that of beta1- and beta2-adrenoceptors, induces a decrease in contractility through presently unkno...

The present study was designed to verify our previous hypothesis that carteolol, a beta1/beta2-adrenoceptor-blocking agent, is a nonconventional partial agonist of cardiac beta1-adrenoceptors. To this purpose, we characterized the effects of carteolol in guinea pig myocardial preparations and measured the affinities of carteolol for high- and low-affinity sites of beta1-adrenoceptors labeled by...

Gorman, Mark W., Martin Farias III, Keith N. Richmond, Johnathan D. Tune, and Eric O. Feigl. Role of endothelin in -adrenoceptor coronary vasoconstriction. Am J Physiol Heart Circ Physiol 288: H1937–H1942, 2005. First published December 9, 2004; doi:10.1152/ajpheart.01076.2004.—It has been proposed that -adrenoceptor vasoconstriction in coronary resistance vessels results not from -adrenoceptor...

Dexmedetomidine is a highly selective α2-adrenoceptor agonist that demonstrates anxiolytic and analgesic properties without inducing respiratory compromise, which makes it a suitable agent for procedural sedation and imaging studies. In our current case reports, intravenous dexmedetomidine infusion was used to provide sedation to 2 pediatric patients over more than 20 sessions of radiation ther...

β2-Adrenoceptor (β2-AR) agonists promote muscle growth. The aim of this study was to elucidate some effects of the selective β2-adrenoceptor agonist clenbuterol (CLB) on myoblast proliferation. We found that CLB induces cell cycle arrest in C2C12 myoblasts. This effect is partly due to the enhanced stability of p27, rather than the increased gene transcription via cAMP response element-binding ...

Severe asthma is the most common respiratory emergency treated in casualty departments of most hospitals. Intravenous aminophylline has been the mainstay of bronchodilator treatment for several years, although sudden death may occur after rapid administration,1 2 and it may be cardiotoxic.3 We thought that a selective adrenoceptor agonist might therefore be worthy of trial, and we report here o...