Journal of anesthesia
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Journal of anesthesia · Sep 1995
Dose-dependent effects of repeated ketamine administration on muscarinic acetylcholine receptors in the mouse forebrain.
To study the effects of repeated ketamine administration (0: saline, 12.5, 25, and 50 mg·kg-1 every 3 days for a total of five times, subcutaneously) on the central muscarinic acetylcholine receptors (mAchRs), receptor binding assays of mAchR were carried out in the forebrain of mice, using [3H]quinuclidinyl benzilate ([3H]QNB) as a ligand. We also examined whether repeated ketamine administration could modify the sensitivity to scopolamine (0.5 mg·kg-1) (a muscarinic antagonist). ⋯ Repeated ketamine reduced scopolamine-induced hyperlocomotion at 50 mg·kg-1 (P<0.05). We conclude that repeated ketamine administration produces up-regulation of mAchRs, which is probably associated with the altered Ach transmission of the central nervous system.
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Journal of anesthesia · Sep 1995
Halothane suppresses the increase in intracellular calcium concentration of isolated rat myocytes during hydrogen peroxide perfusion.
Ischemia-reperfusion injury is probably caused by the generation of oxygen free radicals. The final common pathway to cell injury may be mediated by intracellular calcium overloading induced by oxygen free radicals. Volatile anesthetics have been shown to improve myocardial function following reperfusion. ⋯ Halothane delayed the onset of the increase in [Ca2+]i induced by H2O2, whereas sevoflurane and isoflurane accelerated the onset. Furthermore, sevoflurane caused more pronounced accumulation of intracellular calcium than did halothane and isoflurane. Therefore, the reduction of excessive intracellular calcium accumulation caused by halothane may have beneficial effects on myocardial function following reperfusion.
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Journal of anesthesia · Sep 1995
Does cyclosporine affect the duration of action of vecuronium in renal transplant recipients?
The duration of action of vecuronium was tested in 41 surgical patients to evaluate whether cyclosporine modulates the action of vecuronium. The patients were divided into three groups: 12 patients with normal renal function (group A); 14 renal transplant recipients who had received cyclosporine before surgery (group B); and 15 patients with chronic renal failure undergoing surgery other than renal transplantation and who did not receive cyclosporine (group C). ⋯ There was no significant difference in the duration of action of vecuronium between the patients of groups B and C. In summary, cyclosporine did not prolong the duration of action of vecuronium in the renal transplant recipients when the same dose was administered compared with the patients with chronic renal failure who did not receive cyclosporine.
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Journal of anesthesia · Sep 1995
N-methyl-D-aspartate receptor agonists and antagonists partially affect the duration of ketamine anesthesia in the rat.
The effects of intracerebroventricular injection of excitatory amino acids which act on the N-Methyl-D-aspartate (NMDA) receptor complex on the duration of loss of righting reflex (DLRR) induced by intravenous injection to ketamine (20 mg/kg) were investigated in rats. Ketamine-induced DLRR was 10.3 min, but NMDA receptor agonistsD-alanine (200 μg) or NMDA (0.15 μg) did not change DLRR. ⋯ The NMDA receptor antagonist 7-chlorokynurenic acid (10 μg) alone prolonged DLRR significantly (16.2 min), but not when combined withD-alanine. These data suggest that NMDA receptor blockade contributes at least partially to the mechanism of ketamine anesthesia.
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Journal of anesthesia · Sep 1995
Comparison of the placental transfer of halothane, enflurane, sevoflurane, and isoflurane during cesarean section.
The concentrations of placental transfer of halothane (H), enflurane (E), sevoflurane (S), and isoflurane (I) were measured in 46 patients during cesarean section. The mean inhalation times of H (0.5%), E (1%), S (0.8%), and I (0.6%) were 13 min 27 s, 13 min 49s, 13 min 20s, and 8 min 8s, respectively. The mean concentrations in the maternal artery (MA) were 5.2mg·dl-1 in H, 12.3 mg·dl-1 in E, 5.2mg·dl-1 in S, and 2.4mg·dl-1 in I. ⋯ The Apgar scores in these four groups were not different from that in the group given only 66% nitrous oxide in oxygen as anesthetic (N2O group). The cardiovascular changes induced by skin incision were bigger in the N2O group than in the other groups. The use of a low concentration of H, E, S, or I is, therefore, suggested to be a useful and acceptable anesthetic method for cesarean section.