Effect of adrenalectomy on convulsions induced by high-pressure oxygen

A. K. Singh, E. W. Banister

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Adrenalectomized rats exposed to high pressure oxygen (OHP) until convulsion convulse much later than sham-operated or normal rats. No significant changes in the concentration of noradrenaline (NA) and total catecholamines (TC) in the brain were noted in sham-operated or adrenalectomized rats resulting from sham or real surgery and no change occurred in these variables in normal sham-operated or adrenalectomized animals after OHP leading to convulsion. Brain adrenaline (A) concentration, however, decreased significantly in all 3 groups following OHP-induced convulsions. Activity of catecholamine O-methyltransferase (COMT) decreased significantly only in adrenalectomized rats. Brain γ-aminobutyric acid (GABA), glutamate, and other amino acid level remained unchanged after adrenalectomy whereas the concentration of ammonia decreased significantly when normal rats were adrenalectomized. After OHP-induced convulsions, the concentrations of brain GABA and glutamate decreased and ammonia and glutamine plus asparagine increased significantly in normal, sham-operated, and adrenalectomized rats. In the blood no significant difference was noted in the concentration of the catecholamines, ammonia, and amino acids either in normal or sham-operated rats. In adrenalectomized rats, the blood A and NA concentrations decreased significantly and tyrosine increased significantly. The concentration of NA, ammonia, and glutamine plus asparagine in rats from all 3 groups increased after OHP-induced convulsions, whereas the concentration of glutamate decreased significantly. Since the concentration of A increased significantly after convulsions in normal and sham-operated rats but did not change in adrenalectomized rats, it might be proposed that adrenalectomy protects against OHP-induced convulsions by reducing the circulating concentration of A and ammonia. However, these are not the only factors involved in the protection since the sham-operated rats also convulsed much later than normal rats but had similar ammonia and A concentrations to normal animals.

Original languageEnglish (US)
Pages (from-to)688-694
Number of pages7
JournalCanadian Journal of Physiology and Pharmacology
Volume57
Issue number7
DOIs
StatePublished - Jan 1 1979

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