Functional role of endothelial alpha(2)-adrenoceptor in coronary circulation remains unclear. Clonidine, an agonist of alpha(2)-adrenoceptors, was reported to induce coronary vasodilatation via stimulation of endothelial alpha(2)-adrenoceptors or coronary vasoconstriction involving vascular smooth muscle alpha(2)-adrenoceptors. Moreover, H(2) receptor-dependent responses to clonidine were descr...

Experiments were carried out to examine the components of the intracellular second messenger system that is involved in beta 3-adrenoceptor (atypical beta-adrenoceptors)-mediated relaxation in the guinea pig taenia caecum. Propranolol and butoxamine caused competitive antagonism of the relaxant response to isoprenaline. However, propranolol or butoxamine did not significantly affect the relaxan...

This study was performed to distinguish central and peripheral a -adrenoceptors in the inhibition of rat pineal melatonin synthesis. The 2 rats received lipoor hydrophilic a -adrenoceptor ligand injections at middark; after 1 or 2 h the pineal melatonin contents were 2 measured. The lipophilic agonist medetomidine (100 mg/kg s.c.) suppressed the melatonin contents significantly, while the hydro...

Extensive evidence indicates that norepinephrine modulates memory storage through an activation of beta-adrenoceptors in the basolateral nucleus of the amygdala (BLA). Recent findings suggest that the effects of beta-adrenergic activation on memory storage are influenced by alpha1-adrenoceptor stimulation. Pharmacological findings indicate that activation of postsynaptic alpha1-adrenoceptors po...

The preclinical pharmacological profile of indacaterol, a novel, chirally pure inhaled beta(2) adrenoceptor agonist, is described in this chapter. In various in vitro systems, indacaterol is close to a full agonist at the human β2-adrenoceptor with nanomolar potency. In isolated superfused human and guinea pig trachea, indacaterol has a fast onset of and a long duration of action. In the consci...

Systemic subchronic oxytocin treatment significantly and substantially increased the B(max) values of the alpha 2 agonist [(3)H]UK14.304 binding sites in the hypothalamus, the amygdala and the paraventricular thalamic nucleus of the rat as shown by quantitative receptor autoradiography. These results suggest that long-term modulation of autonomic and neuroendocrine functions and emotional behav...

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, in ad...