A pressurized nitrogen counterbalance to cortical glutamatergic pathway stimulation.
Previous microdialysis studies performed in rats have revealed a decrease of striatal dopamine and glutamate induced by nitrogen narcosis. We sought to establish the hypothetical role of the glutamatergic corticostriatal pathway because of the glutamate deficiency which occurs in the basal ganglia in this hyperbaric syndrome. Retrodialysis with 1 mM of Saclofen and 100 mM of KCl in the prefrontal cortex under normobaric conditions led to an increase in striatal levels of glutamate by 95.2% and no changes in dopamine levels. Under 3 MPa of nitrogen and with the infusion, the rate of striatal glutamate decreased by 51.3%, to a greater extent than under pressurised nitrogen alone (-23.8%). The rate of dopamine decreased, which also occurred under pressurised nitrogen (-36.9 and -31.4%, respectively). In conclusion, the function of the corticostriatal pathway is affected by nitrogen under pressure. This suggests that the nitrogen-induced break point seems to be located at the glutamatergic striatopetal neurons.
Vallee
Nicolas
N
Department of Operational Environment, ERRSO, Institut de Recherches Biomédicales des Armées, Antenne Toulon, BP 20548, 83041, Toulon Cedex 9, France. n.vallee@imnssa.net
Rostain
Jean-Claude
JC
Risso
Jean-Jacques
JJ
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001216:Asparagine / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism; D001418:Baclofen / Q000031:analogs & derivatives / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006719:Homovanillic Acid / Q000378:metabolism; D006931:Hyperbaric Oxygenation; D007222:Inert Gas Narcosis / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009584:Nitrogen / Q000494:pharmacology; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley
D005973:Glutamine; D015102:3,4-Dihydroxyphenylacetic Acid; D001224:Aspartic Acid; D018698:Glutamic Acid; D001216:Asparagine; D001418:Baclofen; C080629:saclofen; D009584:Nitrogen; D004298:Dopamine; D006719:Homovanillic Acid