Catecholamine concentration in the developing rat brain after gamma-hydroxybutyric acid

The effect of the GABA receptor agonist gamma-hydroxybutyric acid (GHBA) on brain catecholamine concentration was investigated in 1 to 28 day old rats. The infant rats were given GHBA in various doses (375--1500 mg/kg) and the effects on whole brain or regional brain concentration of dopamine (DA) and noradrenaline (NA) were measured. Brain DA concentration increased in a dose-dependent way already from two days of postnatal age. In the regional brain study of the 14- and 28-day-old animals the increase in DA concentration was found to be almost exclusively located in the striatal region. Generally, no changes in NA concentration were found in the whole brain or various brain regions at any of the ages after GHBA. It is concluded that the inhibitory striatal-nigral neurons, utilizing GABA as a transmitter, are functionally developed during early postnatal age.