Dopamine-dependent inhibition of glycine release in the nucleus accumbens of the rat brain during food consumption.

Studies of Sprague-Dawley rats using in vivo intracerebral dialysis and high-performance liquid chromatography with electrochemical detection were used to investigate glycine release into the intercellular space of the nucleus accumbens during food consumption. The results showed that food consumption led to decreases in glycine levels in the intercellular space of the nucleus accumbens. Administration of the sodium channel blocker tetrodotoxin (1 microM), but not the glutamate reuptake blocker D,L-threo-hydroxyaspartate (1 mM), prevented the food-related behavior-induced decrease in glycine levels in the nucleus accumbens. Eating of food after administration of the dopamine D2 receptor blocker raclopride (10 microM) into the nucleus accumbens was accompanied by an increase in the glycine level in the intercellular space of this structure. These data provide evidence for the neural regulation of glycine release in the nucleus accumbens during food-related behavior, mediated via dopamine D2 receptors.