The development of GABAB-mediated activity in the rat dentate gyrus.
We examined the effects of GABAB receptor activation in the dentate gyrus of hippocampal slices prepared from 6-8-day-old rat pup. Baclofen (0.25-1.0 microM), a GABAB agonist, rapidly and potently disinhibited the developing dentate, similar to its effect in the mature organism. CGP 35348, a GABAB antagonist, quickly reversed the baclofen-induced disinhibition. However, GABAB antagonists did not reverse long-latency (500-1000 ms IPI) paired-pulse depression, suggesting that it is not caused by a late GABAB-mediated IPSP. GABAB-mediated disinhibition of the dentate gyrus can occur by postnatal day 6, providing a powerful mechanism for altering excitability in the developing hippocampus.
DiScenna
P G
PG
Neurobiology Department, Northeastern Ohio Universities College of Medicine, Rootstown 44272.
Nowicky
A V
AV
Teyler
T J
TJ
D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives / Q000494:pharmacology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D006624:Hippocampus / Q000254:growth & development* / Q000378:metabolism*; D066298:In Vitro Techniques; D009943:Organophosphorus Compounds / Q000494:pharmacology; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D018080:Receptors, GABA-B / Q000378:metabolism*
D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D009943:Organophosphorus Compounds; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; C052329:phaclofen; C066430:CGP 35348; D001418:Baclofen