The role of dynorphin A (1-17; Dyn) and its associated kappa opioid receptor (KOR) in nociception represents a longstanding scientific conundrum: Dyn and KOR (Dyn/KOR) have variously been reported to inhibit, facilitate, or have no effect on pain. We investigated whether interactions between sex and pain type (which are usually ignored) influenced Dyn/KOR-mediated antinociception. Blockade of t...

Polycystic ovary syndrome (PCOS) is a complex, multifaceted, heterogeneous disorder, affecting 4% to 18% of reproductive-aged women and is associated with reproductive, metabolic and psychological dysfunction. Evidences from studies on women with PCOS and on an experimental rat PCO model suggest that the sympathetic regulatory drive to the ovary may be unbalanced (disturbance of ovarian noradre...

Chronic opioid exposure induces neuroadaptative changes in several brain systems. Amongst others the alpha adrenergic system appears to be extremely sensitive to opioid exposure and has, therefore, been proposed to play a key role in opiate withdrawal symptoms. In order to better understand the influence of the noradrenergic system in opioid withdrawal and be able to develop new therapeutic str...

BACKGROUND/AIM To assess the therapeutic effects of naloxone and yohimbine on polycystic ovary syndrome (PCOS) in a rabbit model in terms of body weight and endocrinological parameters (luteinizing hormone, insulin, and estradiol). MATERIALS AND METHODS A total of 50 adult, reproductively mature female rabbits (Oryctolagus cuniculus) were divided into five groups (n = 10/group). In the contro...

Effectiveness of E-643, a newly developed alpha-blocker, and four alpha-antagonists in blocking pre- and postsynaptic alpha-adrenoceptors were compared in the isolated rat vas deferens. The inhibitory effect of clonidine on the field-stimulated twitch response was antagonized in the presence of the alpha-antagonist. The order of affinity (pA2) for presynaptic alpha-receptors, as assessed from p...

Ketamine, an NMDA receptor antagonist, is commonly used in combination with xylazine, an alpha 2-adrenergic receptor agonist, to induce surgical anesthesia in birds and other vertebrates. Problems associated with this anesthetic combination include impaired thermoregulation, compounded by the inability to feed while anesthesia lasts (approximately 6 h after a single dose), and the ketamine-indu...

Kreiss, Christianna, Sandra Toegel, and Anthony J. Bauer. 2-Adrenergic regulation of NO production alters postoperative intestinal smooth muscle dysfunction in rodents. Am J Physiol Gastrointest Liver Physiol 287: G658–G666, 2004; 10.1152/ajpgi.00526.2003.— 2-Adrenergic receptor activation plays an important role in the development of postoperative ileus. 2-Adrenergic receptors also regulate ni...

Masuki, Shizue, Frank A. Dinenno, Michael J. Joyner, and John H. Eisenach. Selective 2-adrenergic properties of dexmedetomidine over clonidine in the human forearm. J Appl Physiol 99: 587–592, 2005. First published March 31, 2005; doi:10.1152/japplphysiol.00147.2005.— We tested the hypothesis that dexmedetomidine (Dex) has greater 2vs. 1 selectivity than clonidine and causes more 2-selective va...

The purpose of this study was to determine whether both a,and a,-adrenergic receptors exist on vascular smooth muscle of microvessels and whether adrenergic constriction of anatomically distinct microvascular segments is differentially subserved by either receptor subtype. The cremaster skeletal muscle of anesthetized rats was acutely denervated and suspended in a Krebs bath containing cocaine,...

Patients with autonomic failure have disabling orthostatic hypotension because of impaired sympathetic activity. Norepinephrine transporter blockade with atomoxetine raises blood pressure in autonomic failure by increasing synaptic norepinephrine concentrations in postganglionic sympathetic neurons. This effect requires tonic release of norepinephrine, which is decreased in patients with low sy...