Effect of gammahydroxybutyric acid on serotonin synthesis, concentration and metabolism in the developing rat brain.

5-HT synthesis, levels and degradation were investigated in the whole brain and regional brain areas in 4, 14, and 28 days old rats after administration of gammahydroxybutyric acid (GHBA). 5-HT synthesis was investigated by means of 5-HTP accumulation after decarboxylase inhibition by NSD 1015. 5-HTP accumulation increased in the 14 and 28 days old rats but decreased in the 4 days old animals 90 min after GHBA, 750 mg/kg. In the 28 days old rats a corresponding increase was also noted in the precursor amino acid tryptophan. Regional and whole brain 5-HT levels were not altered by GHBA treatment. Regional as well as whole brain levels of 5-HIAA increased in the 14 and 28 days old rats after GHBA administration. In conclusion, the present data indicate that GHBA increases the synthesis and degradation of 5-HT in adolescent rats. These effects of GHBA were not seen in the neonatal animals.