AIM To elucidate the involvement of noradrenergic system in the mechanism by which diazepam suppresses basal hypothalamic-pituitary-adrenal (HPA) axis activity. METHODS Plasma corticosterone and adrenocorticotropic hormone (ACTH) levels were determined in female rats treated with diazepam alone, as well as with diazepam in combination with clonidine (α(2)-adrenoreceptor agonist), yohimbine (α...

BACKGROUND Coronary flow reserve (CFR) is not normalized shortly after coronary stenting. We hypothesized that alpha-adrenergic coronary vasoconstriction acts to limit CFR. METHODS AND RESULTS We assessed flow velocity by Doppler wires and cross-sectional area by angiography in 46 patients undergoing coronary culprit lesion stenting (81+/-4% stenosis). Hyperemia was induced by adenosine (24 m...

Antibodies were raised against a newly synthesized analog (CP57.609) of the o,-selective antagonist prazosin, and against the a.-selective antagonist, yohimbine, by Immunization of rabbits with antigens prepared by covalent linkage of these Uganda to albumin. Competitive Inhibition of [H]prazosln binding to anti-CP57,609 antiserum by a variety of nnlabeled Uganda revealed a spectrum of antibody...

In this study using clonidine (a mixed ?2 /I1 receptors agonist), tizanidine (pure ?2-receptor agonist), rilmenidine (I1 receptor agonist) and yohimbine (?2-receptor antagonist), we tried to clarify the role of imidazoline and ?2-receptors in morphine withdrawal syndrome. Morphine-dependence was induced by administration of increasing doses of morphine in mice. After the last administration of ...

In this study using clonidine (a mixed ?2 /I1 receptors agonist), tizanidine (pure ?2-receptor agonist), rilmenidine (I1 receptor agonist) and yohimbine (?2-receptor antagonist), we tried to clarify the role of imidazoline and ?2-receptors in morphine withdrawal syndrome. Morphine-dependence was induced by administration of increasing doses of morphine in mice. After the last administration of ...

objective: tthe objective of this study was to assess the efficacy and safety of sx (combination of yohimbine and l-arginine) in the treatment of erectile dysfunction (ed) methods: this trial was a 4-week, double blind study of parallel groups of patients with mild to moderate ed. forty married male patients with ed of mild-to-moderate severity were screened for the study entry;among them, thos...

This study was designed to elucidate the possible participation of L-type calcium channels in the expression of clonidine-withdrawal precipitated by yohimbine in clonidine-dependent animals. Mice implanted for 5 days with osmotic minipumps containing the alpha 2-adrenoceptor agonist clonidine showed symptoms of a withdrawal syndrome (jerks, headshakes, defecations and weight loss) when yohimbin...

BACKGROUND/OBJECTIVE In the present study, the effect of acute lead exposure in the presence and absence of dopamine or alpha (alpha)-adrenoceptor agents on contractile response of rat isolated thoracic aorta was studied. METHODS Male Wistar rats were used in all experiments. Thoracic aorta was carefully removed, cleaned, and cut into 2-mm thick rings. The rings were mounted for measurement o...

-According to the "epinephrine hypothesis," circulating epinephrine taken up by sympathetic nerves is coreleased with norepinephrine during sympathetic stimulation and binding of coreleased epinephrine to presynaptic beta-adrenoceptors augments exocytotic release of norepinephrine, contributing to high blood pressure. This study examined whether infusion of a physiologically active amount of ep...