Developmental change of GABA(A) receptor-mediated current in rat hippocampus

Developmental change of GABA(A)ergic inhibitory postsynaptic current in rat hippocampal CA3 region was examined using patch-clamp recording method. Sp ontaneous and evoked inhibitory postsynaptic currents were recorded from ac ute hippocampal slices of neonates (postnatal days 2-4) and adults (days 18 -38). Decay kinetics of the spontaneous inhibitory postsynaptic current was slower in neonates than in adults. Application of 500 nM zolpidem increase d decay time-constants of the inhibitory postsynaptic currents in both grou ps with a stronger effect on adults. Zinc (50 mu M) inhibited the neonatal inhibitory postsynaptic currents but the inhibition was weaker in adults. M odification of the GABA(A)ergic inhibitory postsynaptic currents by furosem ide (0.6 mM) or diazepam (100 nM) did not cause marked differences between the neonate and adult groups. These results demonstrate that GABA(A)ergic inhibitory postsynaptic current s in hippcampal CA3 pyramidal cells change developmentally and indicate tha t different receptor isoforms are functionally expressed between neonates a nd adults. (C) 2000 IBRO. Published by Elsevier Science Ltd.