PubMed · 14908322
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B C CORBUS, A D BOYD. 1952. Urological anesthesia.. https://pubmed.ncbi.nlm.nih.gov/14908322/
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Positron emission tomography (PET) measurements in 6-month-old F344/N rats were performed in the conscious state and the influence of chloral hydrate, ketamine, and pentobarbital anesthesia on dopamine D(1) (DA-D(1)) receptor binding was evaluated using [(11)C]SCH23390, a selective DA-D(1) receptor ligand. To perform the PET study in conscious rats, an original fixation apparatus was developed and the animals were trained to acclimate to the scanning atmosphere for 3 h. This training was carried out twice a day for 2 weeks. PET measurements in conscious rats were successful, since the trained rats scarcely moved during the scanning (as monitored by video camera) and since highly reproducible measurements of binding potential (BP) were derived from their scanning. Chloral hydrate and ketamine anesthesia significantly increased the striatal BP of DA-D(1) receptors by 36% and 46%, respectively, compared to that observed in the conscious state. In contrast, pentobarbital markedly decreased the BP by 41%. These BP values of DA-D(1) receptors were calculated using a curve-fitting method. Our results indicate that PET studies in rats should be performed in the conscious state since the anesthetics dramatically modified ligand-receptor bindings, such as DA-D(1) receptor binding, in rat brain.
Neuropathic pain arising from peripheral nerve injury is a clinical disorder characterized by a combination of spontaneous pain, hyperalgesia and tactile pain (allodynia), and remains a significant clinical problem since it is often poorly relieved by conventional analgesics. To seek an analgesic compound(s) in Chinese herbs, we examined the effect of seven Chinese herbs that are routinely prescribed for pain management in two neuropathic pain models: allodynia induced by intrathecal administration of prostaglandin F2alpha (PGF2alpha) and by selective L5 spinal nerve transection. The extracts of Moutan cortex and Coicis semen dose-dependently alleviated the PGF2alpha-induced allodynia by oral administration 1 h before intrathecal injection of PGF2alpha. When orally administrated every day for 7 days, these extracts attenuated neuropathic pain in the ipsilateral side, but not in the contralateral side, day 7 after L5 spinal nerve transection. The increase in NADPH diaphorase activity in the spinal cord associated with neuropathic pain was also blocked by these extracts. These results suggest that Moutan cortex and Coicis semen contain substances effective in neuropathic pain.
Trimetazidine is a widely used anti-ischemic agent, but its effect on myocardial preconditioning in anesthetized animals has not been investigated. The aim of this study was to examine the effects of trimetazidine on ischemic preconditioning and carbachol preconditioning in anesthetized rats. Ischemic preconditioning, induced by 5-min coronary artery occlusion and 5-min reperfusion, decreased the incidence of ventricular tachycardia and abolished the occurrence of ventricular fibrillation during 30-min ischemia. Trimetazidine (10 mg/kg, i.v.) alone attenuated these parameters of arrhythmia. Carbachol infusion induced preconditioning with a marked depression of mean arterial blood pressure, heart rate and ventricular tachycardia. The marked reductions in parameters of arrhythmia induced by ischemic preconditioning and carbachol preconditioning were preserved in the presence of trimetazidine. Arrhythmia scores and myocardial infarct size were significantly reduced with ischemic preconditioning or carbachol preconditioning and were not inhibited by trimetazidine. These results show that trimetazidine protects the heart against ischemia-induced arrhythmias, reduces myocardial infarct size, preserves the effects of ischemic preconditioning and pharmacological preconditioning, and is able to mimic ischemic preconditioning in anesthetized rats.