RT Journal Article
SR Electronic
T1 Recruitment of Early Postnatal Parvalbumin-Positive Hippocampal Interneurons by GABAergic Excitation
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 110
OP 115
DO 10.1523/JNEUROSCI.4125-09.2010
VO 30
IS 1
A1 Jonas-Frederic Sauer
A1 Marlene Bartos
YR 2010
UL http://www.jneurosci.org/content/30/1/110.abstract
AB GABAergic synaptic inputs targeting cortical principal cells undergo marked changes in their functional properties from depolarizing at early postnatal life to hyperpolarizing at mature stages. In contrast, the nature of GABAA receptor-mediated signaling in interneurons during maturation of neuronal networks is controversial. By using gramicidin perforated-patch and whole-cell recordings from LIM homeobox 6 (Lhx6)-positive dentate gyrus perisomatic-targeting parvalbumin-expressing interneurons (PV-INs), we show that signaling at first formed GABAergic synapses at postnatal day 3 (P3) is excitatory and switches to shunting during the course of the first to second postnatal week. GABAergic synaptic inputs at P3–P6 reliably evoke action potentials in 65% of Lhx6-EGFP-expressing perisomatic-targeting cells and boost spike induction upon conjoint activation of glutamatergic fibers. Thus, GABAergic inputs change their functional role during maturation. They facilitate the recruitment of perisomatic-targeting INs in early postnatal circuits when network connectivity and synaptic glutamate receptor-mediated excitation are low and control spike timing at later stages when connectivity and glutamate-mediated drive are high.