Depression of Excitatory Amino Acid Neurotransmitters in Brain During Carbon Dioxide Narcosis, Anesthesia, and Hypoxia: Glutamic Acid and Aspartic Acid
Application of the excitatory amino acid neurotransmitters aspartic acid and glutamic acid to respiratory center neurons in the medulla causes an increase in neuron output (Toleikis et al., 1979). When neurotransmitter amino acids are delivered to the surface of the medulla by means of ventriculocisternal perfusion or application directly to the ventral surface, glutamic acid increases ventilation and gammaaminobutyric acid (GABA) depresses ventilation (Hoop et al., 1985; Systrom et al., 1985; Gatti et al., 1985). The present investigation was undertaken to determine whether hypercapnia at levels associated with CO2 narcosis in man is accompanied by changes in the concentration of endogenous amino acid neurotransmitters in dorsal and ventral medulla of the brain. The aim of this study is to provide support for the hypothesis that reduction of glucose-derived endogenous excitatory amino acid neurotransmitters and elevation of depressant amino acid neurotransmitters contribute to impairment and even depression of the ventilatory response to carbon dioxide at higher inhaled CO2 concentrations (Eisele et al., 1967).
KeywordsVentilatory Response Amino Acid Neurotransmitter Inhibitory Amino Acid Brain Gaba Dorsal Medulla
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- Berkman, R.A., Meyer, K.T., Rosenberg, A.G., and Dutton, R.E., 1978, Depressant effect of ammonia on the ventilatory response to hypoxia and hypercapnia, in: “The Regulation of Respiration during Sleep and Anesthesia”, R.S. Fitzgerald, H.Gautier, S. Lahiri, eds., Plenum Press, New York.Google Scholar
- Eisele, J.H., Eger II, E.I., and Muallem, M., 1967, Narcotic properties of carbon dioxide in the dog, Anestehesiology 28: 856.Google Scholar
- Engelsen, B., 1986, Neurotransmitter glutamate: its clinical importance. Acta Neurol. Scand. 74: 337.Google Scholar
- Gatti, P.J., Taveira da Silva, A.M., Hamosh, P., and Gillis, R.A., 1985, Cardiorespiratory effects produced by application of L-glutamic and kainic acid to the ventral surface of the cat hindbrain, Brain Res. 330: 21.Google Scholar
- Hitzig, B.M., Kneussl, M.P., Shih, V., Brandstetter, R.D., and Kazemi, H., 1985, Brain amino acid concentrations during diving and acid-base stress in turtles, J. Appl. Physiol. 58: 1751.Google Scholar
- Hoop, B., Shih, V.E., and Kazemi, H., 1985, Relationship between central nervous system hydrogen ion regulation and amino acid metabolism in hypercapnia. II, Am. Rev. Resp. Dis. 132: 248.Google Scholar
- Renzetti A.D. Jr., Harris, B.A., and Bowen, J.F., 1974, Influence of ammonia on respiration, J. Appl. Physiol. 16: 703.Google Scholar
- Systrom, D., Hoop, B., Pappagianopoulos, P., and Kazemi, H., 1985, Interaction between GABA and glutamate in central control of cardiorespiratory function, Am. Rev. Resp. Dis., 131: A291.Google Scholar