Development of benzodiazepine binding subtypes in three regions of rat brain

An examination of the development of benzodiazepine binding of the high and low affinity triazolopyridizine (TPZ) type was undertaken in rat cortex, hippocampus and cerebellum. Various concentrations of a typical triazolopyridizine, CL-218-872, were used to displace [3H]flunitrazepam from synaptosomal fractions from rats of postnatal ages day 0, 7, 14, 21, 35 and 70. In contrast to the cortex and cerebellum, hippocampus displays high affinity TPZ binding at birth, prior to the periods of dendritic elaboration and synaptogenesis, suggesting that adult proportions of high and low affinity sites are maintained throughout postnatal development. Delayed postnatal development of high affinity TPZ sites is observed in the cerebellum, similar to the postnatal development previously observed in the cortex.