Glutamate anesthetics

For many years it was believed that the brain mechanisms underlying the effects of psychedelic hallucinogens and dissociative anesthetics were separate and distinct. Indeed, there has been considerable debate about which represents the best drag model of schizophrenia. However, recent data show that the two classes of psychotomimetic drags share a common final pathway involving an increase in the release of the excitatory neurotransmitter glutamate. 

Ramirez-Munguia N, Vera G, Tapia R. 2003. Epilepsy, neurodegeneration, and extracellular glutamate in the hippocampus of awake and anesthetized rats treated with okadaic... 

The mechanisms of action of the effects of alcohol on the nervous system remain unclear. For some time, researchers thought that the depressant effects of alcohol, like other anesthetic agents, were caused by dissolving into the cell lipid membranes and disrupting the function of various proteins. More recently, researchers have focused on specific receptors such as glutamate (excitatory) and GABA (inhibitory). Despite intensive research, the mechanism of effect of alcohol on the fetus is unknown. 

Fig. 2. Transient retinal ischemia increases intravitreal glutamate in rat. Neurochemical data from microdialysis experiments carried out in anesthetized rats to demonstrate that ischemia/reperfusion insult increases intravitreal glutamate. The extracellular level of glutamate shows a moderate increase during the first 10 min of ischemia, more evident toward the end of the ischemic period, to reach statistical significance at 10 and 150 min of reperfusion. Baseline glutamate concentrations (basal values) are the mean concentrations obtained by averaging six samples collected consecutively at 10 min intervals immediately before the onset of ischemia (n — 6 rats). Glutamate values (pM) are expressed as mean S.E.M. Statistical significance was assessed by ANOVA followed by Dunnett s test for multiple comparisons. P < 0.05 and P < 0.001 versus basal values.

BlievichU. M Zomow M. H Choi K. T Stmat M. A., and ScheBerM. S. (1994) Effects of hypothermia or anesthetics on hippocampal glutamate and glycine concentrations after repeated transient global cerebral ischemia. Anesthesiology 80, 177-186. 

Inhalation anesthetics are nonselective in their action. That is, in addition to their clinically important effect on the central nervous system (CNS), they also alter the function of various peripheral cell types. The fact that chemically unrelated molecules produce a state of general anesthesia argues against a specific anesthetic receptor. Further, whereas anesthetics alter the function of receptors for neurotransmitters (for example, y-aminobutyric acid, glutamate),... 

Wakamatsu et al. (1999), Ohtake et al. (2000), Oka et al. (2001) studied the effects of intrathecally administered local anesthetics on glutamate release and neuronal injury in rabbits. New Zealand white rabbits were anesthetized with isofluorane. With the rabbits in prone position, midline skin and subcutaneous fascia were incised between the third lumbar and the first... 

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