The protection against the cerebral and pulmonary effects of hyperbaric oxygen by pharmacological agents and lithium salts in mice

The effect of three phenothiazines, a barbiturate, a ureide, two oxazolidine diones, γ-aminobutyrate, γ-hydroxybutyrate and n-dipropylacetate, in diminishing the incidence of convulsions and pulmonary oedema induced by hyperbaric oxygen at pressures up to 6 bars was studied in mice. The order of effectiveness in protection was chlorpromazine (6 mg/kg) > LiCl (600 mg/kg) > γ-hydroxybutyrate (200 mg/kg) > prochlorpemazine (5 mg/kg) > phenobarbitone (5 mg/kg). If a drug protected the mouse against convulsions, the pulmonary hydration did not increase. The findings generally supported the hypothesis that the protection from hyperbaric oxygen was due to these drugs preventing the fall of γ-aminobutyrate in the brain caused by hyperbaric oxygen.