Ontogenetic properties of benzodiazepine receptor subtypes in rat spinal cord

A differential postnatal development of cortical benzodiazepine (BZ) receptor subtypes in rat cortex in which the densities of BZ-Type II, but not Type I receptors, increased in number during the first two neonatal weeks has been reported. The authors sought to determine the relative ratios of BZ-Type I/Type II receptors in the spinal cord of neonatal and adult animals. The present report, demonstrates that the ratio of BZ receptor subtypes in neonatal spinal cord approximates that of neonatal cortex and cerebellum (i.e. BZ-Type I similar to 10%, BZ-Type II similar to 90%); however, unlike cortex and cerebellum, this ratio in spinal cord does not substantially change with age.