Articles: anesthetics.
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Dexmedetomidine, a highly selective and potent alpha-2 adrenoceptor agonist, reduces halothane anesthetic requirements by over 90% in rats. The present study examined whether dexmedetomidine produces a hypnotic-anesthetic action in rats. Dexmedetomidine induced a hypnotic-anesthetic state in rats characterized by loss of righting reflex at doses greater than or equal to 0.1 mg/kg. ⋯ Antagonists with beta-2 receptor blocking properties also enhanced dexmedetomidine-induced hypnosis. Selective beta-1 receptor antagonists did not affect the hypnotic action of dexmedetomidine. These results suggest that dexmedetomidine produces a hypnotic-anesthetic action in rats via activation of central alpha-2 adrenoceptors.
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Acta Anaesthesiol Scand · Jul 1989
Randomized Controlled Trial Comparative Study Clinical TrialComparative clinical study of induction and emergence time in sevoflurane and enflurane anaesthesia.
The induction and emergence times in patients who received minor oral surgery under sevoflurane with nitrous oxide or enflurane with nitrous oxide were compared. The induction time required for the loss of eyelid reflex when using sevoflurane (1.6 +/- 0.2 min) was significantly shorter than that in the enflurane group (2.9 +/- 0.4 min). There was no significant difference in the recovery time in the two groups.
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J. Pharmacol. Exp. Ther. · Jul 1989
Quantitative histologic analysis of local anesthetic-induced injury to rat sciatic nerve.
Quantitative measurements of endoneurial edema, cytoplasmic lipid droplets, nerve fiber injury and Schwann cell damage were used to elucidate the pathogenesis of local anesthetic-induced injury to sciatic nerve in the rat. All histopathologic measurements were conducted on rat sciatic nerves removed at 48 hr after the extraneural injection of one of three concentrations of the local anesthetic 2-chloroprocaine, procaine, etidocaine or lidocaine. ⋯ Quantitative electron microscopic evaluation of Schwann cell injury indicated that the Schwann cells of unmyelinated fibers were more likely to undergo lysis after exposure to local anesthetics, whereas those of myelinated fibers were more likely to accumulate cytoplasmic lipid droplets. These quantitative data on the specificity of the regional distribution of nerve injury and of Schwann cell effects are consistent with a direct cellular toxicity of the local anesthetics; however, these results do not preclude a role for toxicity mediated indirectly by changes in the endoneurial environment.