Effect of ethanolamine- O-sulphate on regional gaba metabolism in the mouse brain

Abstract

The distribution of [ 3 H]ethanolamine-O- sulphate (EOS) and the regional changes in GABA metabolism after 160 μg (8 mg/kg) intracerebroventricularly and 2 g/kg subcutaneously have been studied in the mouse brain. Over 60 per cent of the injected radioactivity (given i.c.v.) was lost within the first hr. That remaining at 24 hr, however, after subcellular fractionation appeared to be associated with GABA-transaminase (GABA-T). The greatest binding occurred in the hypothalamus, an area with a high endogenous GABA concentration and the highest turnover rate of those areas studied. GABA turnover rates calculated over a 4 hr period for both 160 μg i.c.v. and 2 g/kg s.c. correlated (P < 0.001) with the endogenous GABA concentrations. EOS 2 g/kg s.c. was as effective as 160 μg i.c.v. in inhibiting GABA-T in the brain, but has a slower onset of action. The possibility of a larger GABA-T pool in the hypothalamus than in the other areas studied is discussed.