Cell proliferation in response to GABA in postnatal hippocampal slice culture.

Recent studies have implicated the inhibitory neurotransmitter GABA in the regulation of cell migration and proliferation in the embryonic brain. Herein, we examine the possibility that these effects are maintained postnatally. Using 5 days postnatal hippocampus, we tested GABA effects on growth into an incision made in CA1 and the possibility that this response to GABA is mediated via GABA(A)-receptor. Our data shows that GABA promotes neurite growth, cell proliferation and migration up to day 6 in vitro. GABA(A)-receptor is not involved in the trophic response to either exogenous or endogenous GABA. Moreover, GABA induced a 20% increase in NGF secretion to the growth medium, in a similar time frame to its effect on growth. Elevated NGF secretion was suppressed by the inhibition of cell proliferation. These results suggest that GABA can promote growth in postnatal hippocampal tissue. The effect involves cell proliferation and NGF secretion and does not depend on GABA(A)-receptor activation.