We have investigated the effects of systemic administration of two N-methyl-D-aspartate (NMDA) receptor antagonists and two opiate agonists on nociception during and after tail ischaemia in conscious ...rats. The two NMDA receptor antagonists, D-2-amino-5-phosphonovalerate (APV) and ketamine hydrochloride, did not alter tail flick latencies in rats not subjected to ischaemia but inhibited post-ischaemic hyperalgesia (PIH) in a dose-dependent manner. Neither of these agents impaired motor function of the rats, as assessed by rotarod performance, suggesting a purely sensory antinociceptive effect. The antinociceptive effect of APV during reperfusion following ischaemia was not antagonised by the mu-opiate receptor antagonist naloxone (1 mg/kg). The two opiate receptor agonists, morphine and pethidine, increased tail flick latencies in rats not subjected to ischaemia, inhibited PIH in a dose-dependent manner, and also caused significant motor malfunction, all in naloxone-reversible fashion. We conclude that the role of the NMDA receptor in mediating afferent nociceptive traffic is confined to its involvement in neuronal events mediating hyperalgesia.
Analyzes the use of problem-based learning as a catalyst for developing and implementing curriculum for gifted students that is both challenging and constructivist in approach. It relates ...metacognition to problem-based learning and describes inservice programs developed for teachers and administrators at the College of William and Mary (Virginia). (DB)
Alcohol consumption and alcohol expectation were separately evaluated in terms of effects on psychophysiological levels prior to stress and reduction of the magnitude of response to stress. 96 male, ...experienced drinkers were assigned to 8 conditions in a between-Ss design in which beverage consumed (alcohol or tonic), beverage expected (alcohol or tonic), and stressor (self-disclosing speech or threat of shock) were manipulated. Dosage for Ss receiving alcohol was 1 g ethanol/kg. Results indicate strong effects of alcohol consumption on prestress levels, consisting of accelerated heart rate (HR), lower HR variability, higher skin conductance, longer pulse transmission time (PTT), higher "cheerfulness" and lower "anxiety" ratings. Alcohol consumption significantly reduced the magnitude of the HR, PTT, and anxiety responses of Ss to the stressors. No effects attributable to alcohol expectation were found. Results are integrated with the existing literature concerned with pharmacological and cognitive effects of alcohol as they pertain to stress, psychophysiological responses to stress, and tension reduction. (32 ref)
