AGE-RELATED-CHANGES IN [H-3] BACLOFEN BINDING IN MOUSE CEREBELLUM

1. Specific [H-3]baclofen binding to cerebellar membranes from 1-month -old (young), 8-month-old (older) and 20-month-old (aged) mice was low er than that to membranes from 3-month-old mice (mature adult), wherea s in cerebral cortical membranes there were no age-related changes in [H-3]baclofen binding among the four age groups. 2. Scatchard analysis revealed that the density of cerebellar GABA(B) receptors significant ly decreased during aging. 3. There were no age-related changes in the inhibitory effect of Gpp(NH)p on [H-3]baclofen binding. 4. These resu lts suggest that the characteristics of GABA(B) receptors in the cereb ellum change during aging without any alteration in the coupling of th e receptor to guanine nucleotide regulatory proteins.