Postnatal development of high affinity neuronal recognition sites for 3H-5-HT in rat brain

The postnatal development of 3H-5-HT specific binding sites has been studied in rat brain. Experimental conditions allowed the characterization of the class of sites corresponding to the synaptosomal receptor for 5-HT. The related affinity constant and maximal binding were measured at various ages after birth. During the second week after birth, the serotonin receptor system developed explosively, the maximal number of sites increasing from a nonsignificant value to that observed in adult rats. Lesion of the presynaptic neurons using 5,6-DHT led to a significant increase of the number of sites.