The density of GABAB binding sites in the substantia nigra is greater in rat pups than in adults.
Baclofen-displaced [3H]GABA (gamma-aminobutyric acid) binding to GABAB sites was assayed in brain regions obtained from adult and 14- to 17-day-old rats. The substantia nigra of rat pups exhibited a 3- to 5-fold higher density (Bmax) of GABAB binding sites than the nigra of adult rats. In contrast, the density of GABAB sites was lower in hippocampal and cerebellar tissue from pups, both approximately two-thirds the density in corresponding adult structures. This anatomically selective overproduction of GABAB receptors in immature substantia nigra is consistent with the increased anticonvulsant efficacy of the GABAB agonist baclofen observed in rat pups.
Garant
D
D
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461.
Sperber
E
E
Moshé
S
S
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001418:Baclofen / Q000494:pharmacology; D001665:Binding Sites; D005260:Female; D008297:Male; D051381:Rats; D011963:Receptors, GABA-A / Q000032:analysis*; D013378:Substantia Nigra / Q000737:chemistry*
D011963:Receptors, GABA-A; D001418:Baclofen