AIM ETA receptor antagonists reverse opioid tolerance but the involvement of ETB receptors is unknown. In morphine or oxycodone tolerant mice we investigated (1) the effect of ETB receptor agonist, IRL-1620, on analgesic tolerance; (2) changes in expression of the brain ETA and ETB receptors; and (3) alterations in the brain VEGF, NGF, PI3K and notch-1 expression. MAIN METHODS Body weight, bo...

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The action mechanism for the production of spinal analgesia of KK-3, tyrosyl-N-methyl-gamma-aminobutylyl-phenylalaninol, was examined by the tail pinch and tail flick methods. Intrathecal KK-3, 2.5, 5 and 10 nmol/mouse, dose-dependently produced an analgesic effect in both methods. In the tail pinch method, the analgesia was suppressed by 2 mg/kg but not by 1 mg/kg of naloxone; however, the ana...

Purpose: To investigate the anti-inflammatory and analgesic activities of the Amorphophallus Bulbifer in Wistar rats and mice. Methods: The anti-inflammatory activity of the hydroalcohol extract of A. bulbifer whole plant at dose levels of 100 and 200 mg/kg p.o. in rats was determined with a plethysmograph paw volume difference of the animals preand post-treatment. Ibuprofen (10 mg/kg) was empl...

Prior work suggests that spinal systems are sensitive to the stimulus relationships that underlie Pavlovian conditioning. We studied this phenomenon in Sprague-Dawley rats by pairing a vibrotactile conditioned stimulus (CS) with a tailshock unconditioned stimulus (US). Experiment 1 showed that spinal rats exhibit differential conditioning, having longer tail-flick latencies on the tail-flick te...

the antinociceptive effect of elaeagnus angustifolia fruits was studied in mice. the antinociceptive effect of ethanolic and boiling water extracts was studied using two thermal stimuli, the hot-plate and tail-flick tests. the intraperitoneal and oral administration of the ethanolic extract of seed 0.75-7.00 g/kg), but not pericarp and medulla had significant antinociceptive activity in the hot...

introduction: the antinociceptive effect of morphine is, in part, mediated through the activation of a descending pathway. one of the major components of this pathway is the nucleus raphe magnus (nrm). our previous study demonstrated the involvement of nrm in the analgesic effect of morphine microinjected into the nucleus cuneiformis (ncf) in a descending manner. the aim of the current study wa...

First, the antinociception with the tail-flick test of D-Pro-endomorphin-1 and D-Pro-endomorphin-2 given i.t. was compared with that produced by endomorphin-1 and -2 in male CD-1 mice. High doses of D-Pro-endomorphin-1 (0.2–0.4 pmol) and D-Pro-endomorphin-2 (300–800 pmol) given i.t. produced antinociception with low intrinsic activity [about 25% maximum possible effect (MPE)] compared with that...