We reported previously that nitrous oxide induces pre-emptive analgesia that is partially antagonized by naloxone and totally antagonized by halothane. The aims of this study were to determine if halothane and isoflurane are similar in this respect and to examine if volatile anaesthetics antagonize the analgesic effect of exogenous opioids. We found that 75% nitrous oxide prolonged tail-flick l...

The antinociceptive effects of MDMA and morphine were examined in rats using the tail-flick and hot-plate analgesiometric tests. MDMA, in the dose range of 1.5-6.0 mg/kg IP, produced a dose-dependent elevation in hot-plate latency, but did not elevate tail-flick latency. In contrast, morphine (2-8 mg/kg, IP) produced analgesia on both the tail-flick and hot-plate tests in a dose-dependent manne...

Environmental noise is a known stress, which induces alterations of various physiological responses in individuals exposed to it. Stress has been shown to cause changes in the perception of various sensations including pain and stress-induced analgesia has been observed following exposure to a diverse set of stimuli. To examine the algesic behavior of rats exposed to loud environmental noise, f...

We have studied rats with chronically implanted subarachnoid catheters. Xylazine, an alpha 2 adrenoceptor agonist, was injected intrathecally and nociceptive thresholds measured at two skin sites: the tail and the neck. Intrathecal xylazine (dose range 24.3-389 nmol) produced increases in electrical thresholds for nociception in the tail without any change in the neck; this observation suggeste...

The effect of morphine on regional cerebral glucose metabolism was measured in rats using high resolution [14C]2-deoxyglucose autoradiography with concurrent confirmation of morphine-induced analgesia measured by tail-flick latency to noxious heat. Within the limits of resolution of this technique, doses of morphine sufficient to inhibit the tail-flick reflex had no significant effect on glucos...

conclusions these findings suggest that apelin does not play any significant role in regulating the pain threshold in type 1 diabetes mellitus during exercise training. results plasma apelin level was higher (0.3 vs. 0.1, p < 0.0001) and the tail-flick latency was lower (2.2 vs. 3.8, p < 0.0001) in the d group than in the nd group. after the training program, plasma apelin levels decreased in t...

Recent neuroanatomical and behavioral evidence has indicated that vasopressin (VA) increases pain threshold. The dorsal raphe nucleus (DRN) is an important nucleus in pain modulation. Anatomical studies have shown that DRN receives vasopressinergic fibers originating in the hypothalamic paraventricular nucleus. The aim of the present study was to examine the effects of intra-DRN injection of de...

We have studied the involvement of the N-methyl-D-aspartate receptor (NMDAR) glycine site and the strychnine-sensitive glycine receptor (GlyR) in the ventrolateral periaqueductal gray (VL-PAG) on nociceptive behavior (tail flick) and pain-related changes on neuronal activity in the rostral ventromedial medulla (RVM). Glycine or D-serine increased the tail-flick latency, reduced OFF-cell pause, ...

backround and aim: in the present time, analgesic and anti-inflammatory drugs such as nonseroidal anti-inflammatory drugs and opioid compounds are used for the releif of pain, but due to their side effects and economical issues, the significance of research on finding analgesic drugs with less side effects and their ability to substitute these synthetic drugs and substituting newer analgesic co...

Recent neuroanatomical and behavioral evidence has indicated that vasopressin (VA) increases pain threshold. The dorsal raphe nucleus (DRN) is an important nucleus in pain modulation. Anatomical studies have shown that DRN receives vasopressinergic fibers originating in the hypothalamic paraventricular nucleus. The aim of the present study was to examine the effects of intra-DRN injection of de...