Effects of inhalation anesthetics of Kainate-induced glutamate release from cerebellar granule cells.
The mechanisms of inhalation anesthesia may include inhibiting non NMDA excitatory amino acid neurotransmission. This possibility was addressed by measuring the effect of three anesthetics at clinically relevant concentration on kainate-induced glutamate release from cerebellar granule cells. Cerebellar granule cells were obtained from 8-day-old SD rats and maintained in vitro for 9-14 days. Medium glutamate concentrations were measured by HPLC after 90 minutes incubation with kainate or NMDA. Inhalation anesthetics were introduced by holding the cells under a continuous flow of air/anesthetic mixtures. All anesthetics tested did not effect NMDA-induced glutamate release. Halothane (1 MAC), isoflurane (1 MAC) inhibited kainate-induced glutamate release from the cultured cells whereas enflurane (1 MAC) had no effect on kainate-induced glutamate release. The difference between enflurane and the other anesthetics tested suggests that anesthesia is dependent on more than one process and the extent at which each function is perturbed is dependent on the specific anesthetic used. Halothane inhibition of kainate-induced glutamate release was not reversible by increasing kainate concentration, indicating halothane does not directly compete with kainate at its receptor.
Zhu
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Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, 39216-4505, USA.
Baker
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RC
D018685:Anesthetics, Inhalation; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D004347:Drug Interactions; D018698:Glutamic Acid / Q000378:metabolism*; D007608:Kainic Acid / Q000494:pharmacology*; D007700:Kinetics; D016202:N-Methylaspartate / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D018685:Anesthetics, Inhalation; D018698:Glutamic Acid; D016202:N-Methylaspartate; D007608:Kainic Acid