Ontogeny of 3H-diazepam binding sites in different rat brain area. Effect of GABA

The ontogenesis of the 3H-diazepam binding sites and their modulation by gamma-aminobutyric acid have been studied in different brain areas of rat at various ages, using frozen and two Triton X-100 treated crude synaptic membrane preparations. Benzodiazepine recognition sites are present at birth in all the brain regions investigated and reach adult levels about 3 weeks later. The changes of 3H-diazepam binding with age are due to an increase in the total number of binding sites. In vitro addition of GABA produces, in newborn and adult cerebral cortex, an increase in affinity, but not in number of binding sites for 3H-diazepam. The effect is age dependent.