Amino acids and ammonia in the cerebral cortex, the corpus striatum and the brain stem of the mouse prior to the onset and after a seizure induced by hyperbaric oxygen

• Published in: Brain research 1995-04, Vol.676 (2), p.352-357
• Main Authors: Mialon, P., Joanny, P., Gibey, R., Cann-Moisan, C., Caroff, J., Steinberg, J., Barthe´le´my, L.
• Format: Article
• Language: English
• Subjects: Amino Acids - metabolism; Ammonia; Ammonia - metabolism; Analysis of Variance; Animals; Basal Ganglia; Biological and medical sciences; Brain; Brain Stem - metabolism; Cerebral Cortex - metabolism; Convulsion; Corpus Striatum - metabolism; Excitatory amino acid; GABA; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Hyperbaric oxygen; Hyperbaric Oxygenation - adverse effects; Male; Medical sciences; Mice; Mice, Inbred C57BL; mouse; Nervous system (semeiology, syndromes); Neurology; Seizures - chemically induced; Seizures - metabolism; Telencephalon - metabolism; Time Factors
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/0006-8993(95)00120-F

The contents of amino acids (AA) and ammonia (NH 3) were measured in corpus striatum, brain stem and cerebral cortex of two strains of mice exposed to hyperbaric oxygen (HBO). Mice of the HBO-sensitive strain (CD1) were exposed to 600 kPa O 2 for 24 min versus 90 min for mice of the normal C57 strain, so that 50% of the mice in both strains developed a generalized convulsion. In the cortex of exposed but unconvulsed (EXUN) C57 mice, the contents of taurine, glutamine and NH 3 increased while that of GABA decreased when compared to control mice. In the CD1 mice, NH 3 content was increased while that of Asp decreased. After a convulsion, NH 3 was increased in both strains, the AA contents returned to normal in C57 but Asp remained low in CD1 mice. Somewhat similar changes occurred in the striatum except that NH 3 levels were less affected while GABA ones were significantly decreased in the CD1 mice exposed to HBO, whether convulsed or not. In the EXUN brain stem, Asp and Glu contents decreased. These decreases were greater in C57 on a percentage basis than in CD1 mice. GABA content was decrease to the C57 strain. After a convulsion, Asp and Glu levels remained low and NH 3 accumulated in CD1 whereas in C57 only the Glu level was decreased. The cortical and striatal changes may indicate a lesser GABA supply in C57 strain and some Asp release in CD1 strain. In the brain stem of both strains, Asp and Glu release is possible in addition to GABA in C57 strain. These data suggest that the excitatory AA, especially Asp, were more involved in the hyperoxic convulsion in the HBO-susceptible CD1 than is GABA. The greatest changes in CD1 as compared to C57 may be due to the faster production of brain lipid peroxides in the former strain.