The present study examined the influence of alpha-2 adrenoceptor ligands on circling behavior in rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal pathway. The alpha-2 adrenoceptor agonists, clonidine and UK 14304, inhibited both the ipsilateral rotation induced by the indirect dopaminergic agonist, methylphenidate, and the contralateral circling induced by the direct dopamine...

Cerebral blood volume and intracranial pressure may be modified by influences on cerebral veins. The known adrenergic innervation of cerebral veins and their sensitivity to norepinephrine raised the question, whether pial veins can be selectively influenced through adrenoceptors in vivo. Therefore, alpha 1 and alpha 2 adrenoceptor agonists and antagonists were locally injected into the perivasc...

1. The effects of beta(3)-adrenergic stimulation were studied on the L-type Ca(2+) channel in single myocytes from rat portal vein using the whole-cell mode of the patch-clamp technique. 2. Reverse transcription-polymerase chain reaction showed that beta(1)-, beta(2)- and beta(3)-adrenoceptor subtypes were expressed in rat portal vein myocytes. Application of both propranolol (a non-selective b...

ρ-Da1a is a three-finger fold toxin from green mamba venom that is highly selective for the α1A-adrenoceptor. This toxin has atypical pharmacological properties, including incomplete inhibition of (3)H-prazosin or (125)I-HEAT binding and insurmountable antagonist action. We aimed to clarify its mode of action at the α1A-adrenoceptor. The affinity (pKi 9.26) and selectivity of ρ-Da1a for the α1A...

Clinical studies conducted with carvedilol suggest that beta-adrenoceptor antagonism is an effective therapeutic approach to the treatment of heart failure. However, many beta-adrenoceptor antagonists are weak partial agonists and possess significant intrinsic sympathomimetic activity (ISA), which may be problematic in the treatment of heart failure. In the present study, the ISAs of bucindolol...

Since the first report of clonidine, an alpha2-adrenoceptor agonist, the indications for this class of drugs have continued to expand. In December 1999, dexmedetomidine was approved as the most recent agent in this group and was introduced into clinical practice as a short-term sedative (<24 hours). Alpha2-adrenoceptor agonists have several beneficial actions during the perioperative period. Th...

transcutaneous electrical nerve stimulation (tens) is an analgesia inducing method with increasing applications in clinical procedures. in this study we tried to evaluate the role of the adrenergic system and its different adrenoceptor subtypes in tens-induced analgesia. two types of low and high frequency electrical stimuli were used in rats through needle electrodes, inserted at the base of t...

The goal of this in vitro study was to examine the effect of the alpha-2 adrenoceptor agonist dexmedetomidine on phenylephrine (alpha-1 adrenoceptor agonist)-induced contraction in isolated rat aortae and to elucidate the associated cellular mechanisms, with a particular focus on alpha-1 adrenoceptor antagonism. Dexmedetomidine dose-response curves were generated in isolated endothelium-intact ...

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 objective of the present study was to evaluate the effects of a selective beta(3)-adrenoceptor agonist, (R, R)-5-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]-1, 3-benzodioxole-2,2-dicarboxylate (CL 316243), on the acutely obstructed ureter in anesthetized dogs. After a complete ureteral obstruction produced by the inflation of a balloon catheter placed within the left lower ureter,...