Ontogenetic development of the specific [3H]nitrendipine binding sites in the rat whole brain

[3H]Nitrendipine binding sites are localized much more in the synaptosomal membrane than in the mitochondrial and microsomal membranes. To use a whole homogenate (crude membrane fraction) for the purpose of observing nitrendipine binding sites in the synaptosomal membrane instead of P2-B fraction has its reason. The Bmax of specific nitrendipine binding in the rat brain increases linearly until it reaches to the adult level after birth. High affinity binding at early developmental stages shifts to low affinity after the 7 day postnatal stage. Autoradiographically, nitrendipine binding sites are rich in the interpeduncular nucleus, olfactory bulb, hippocampus and superior colliculus in an adult rat. In autoradiography, the density in the hippocampus increases gradually until it reaches the adult level at the 28 day postnatal stage.