Clinical and experimental pharmacology & physiology
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Clin. Exp. Pharmacol. Physiol. · May 2007
The effects of isosteviol against myocardium injury induced by ischaemia-reperfusion in the isolated guinea pig heart.
1. This study aimed to investigate the protective effects of isosteviol against myocardial ischaemia-reperfusion (IR) injury and its effects on mitochondrial adenosine triphosphate (ATP)-sensitive potassium channel (mitoK(ATP)) activity in vitro. 2. Groups of eight guinea pigs were treated as follows: constant perfusion control (PC), IR control, ischaemic preconditioning (IPC) + IR, isosteviol (50, 250 or 500 nmol) + IR, 5-hydroxydecanoate acid (5-HD) (5 micromol) + isosteviol (500 nmol) + IR. ⋯ Pretreatment with the mitoK(ATP) blocker 5-HD partially antagonized the effects of 500 nmol isosteviol, with a statistically significant attenuation of its protective effects on HR, LVDevP, dP/dt(max) and dP/dt(min) compared with isosteviol alone pretreatment. 6. The IR injury on the Langendorff perfused guinea pig heart was alleviated by isosteviol, which appears to mediate its effects through mitoK(ATP) channels. Future research might aim to investigate the interaction of isosteviol with mitoK(ATP) channels in order to clarify its mechanism of action.
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Clin. Exp. Pharmacol. Physiol. · May 2007
Studies with ketamine and alfentanil following Freund's complete adjuvant-induced inflammation in rats.
1. N-Methyl-D-aspartate (NMDA) receptor antagonists suppress inflammatory hyperalgesia and the development of acute opioid tolerance. They may also enhance opioid-induced antinociception, while suppressing postopioid-induced hyperalgesia and opioid-enhanced inflammatory hyperalgesia. 2. ⋯ These findings complement previous studies in which non-competitive NMDA receptor antagonists suppressed behavioural hyperalgesia. 7. However, racemic and (S)-ketamine did not further enhance alfentanil's antinociceptive effects, although they appeared to prolong alfentanil's antinociceptive effects in the non-inflamed hind paw. These findings suggest that factors such as time-course, frequency and the mode of administration of NMDA receptor antagonists, in addition to the type of antinociceptive model (i.e. inflammatory compared with acute) and the nociceptive testing procedure (i.e. noxious mechanical compared with low threshold stimuli) may influence their effects on opioid-induced antinociception.
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Clin. Exp. Pharmacol. Physiol. · Jan 2007
The specific free radical scavenger edaravone suppresses bleomycin-induced acute pulmonary injury in rabbits.
1. Intratracheal instillation of bleomycin induces a condition in rabbits that serves as a useful model of human pulmonary fibrosis. Bleomycin-induced production of reactive oxygen species leads to acute lung inflammation and induction of apoptosis, which is followed by pulmonary fibrosis at a later chronic stage. ⋯ In addition, significantly increased numbers of TUNEL-positive (apoptotic) and transforming growth factor-beta-positive cells were seen. All these effects were significantly attenuated by treatment with edaravone. 4. The findings of the present study suggest that edaravone may be useful in the prevention of acute lung injury resulting from the production of reactive oxygen species.
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Clin. Exp. Pharmacol. Physiol. · Jan 2007
Interactions between metoclopramide and morphine: enhanced antinociception and motor dysfunction in rats.
1. Opioid analgesics and anti-emetics are often used concomitantly to treat pain and nausea and vomiting in people with malignant disease. We investigated interactions between the opioid analgesic morphine and the anti-emetic metoclopramide, a dopamine D2 receptor antagonist, on nociception and gross motor function. 2. ⋯ Only the high dose of metoclopramide compromised running performance when administered with saline. However, coadministering morphine with metoclopramide (both doses) decreased motor performance. 5. Therefore, metoclopramide, possibly through its actions on D2 receptors and not 5-HT(3) receptors, enhances the analgesic and antihyperalgesic effects of morphine, but morphine exacerbates metoclopramide-induced motor dysfunction in rats.
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Clin. Exp. Pharmacol. Physiol. · Jan 2007
Effects of hyperbaric oxygen on glucose, lactate, glycerol and anti-oxidant enzymes in the skeletal muscle of rats during ischaemia and reperfusion.
1. Hyperbaric (HBO(2)) and topical oxygen represent two accepted options to oxygenate tissues. The aim of the present study was to investigate the effect of HBO(2) on energy metabolism and anti-oxidant enzymes in a rat model of ischaemia-reperfusion (IR) skeletal muscle injury. 2. ⋯ Catalase activity and MDA increased significantly after 1 h of reperfusion. The HBO(2) attenuated the reperfusion-induced increase in CAT activity and MDA. 6. The results of the study suggest that HBO(2) may have some beneficial effect by decreasing lactate and glycerol levels and modulating anti-oxidant enzyme activity in postischaemic skeletal muscle in our rat model of tourniquet-induced IR skeletal muscle injury.