Abstract: AIM: To investigate the effect of brain-derived neurotrophic factor(BDNF)on GABAA receptor function in cultured hippocampal neurons of rats.METHODS: Primary cultured hippocampal neurons were treated with BDNF (100, 300, or 1000 ng/L) for 20 min, and the intracellular calcium concentration was measured using flow cytometry 5 min after GABA application. GABAA-gated currents were measured using whole cell patch-clamp recordings, the potential was held at -60 mV, BDNF(100, 300, or 1000 ng/L) was applied to the neurons for 2 min, then GABA 100 μmol/L was applied for 5 s, and GABAA-gated currents were recorded. In another experiment, the potential was clamped from 100 mV to 0 mV with increment of 10 mV, GABAA-gated currents were recorded under the influence of BDNF, and the reversal potential of GABAA-gated currents was achieved.RESULTS:After treatment with BDNF 100 ng/L or 300 ng/L, the GABA- induced intracellular calcium concentrations in pyramidal cells were not changed, GABAA-gated currents at -60 mV of the held potential and the reversal potential were not affected. But under the influence of BDNF 1000 ng/L, GABA-induced intracellular calcium concentration in pyramidal cells was increased significantly compared with baseline (P<0.05), GABAA-gated currents were transformed to outward currents at -60 mV of the held pontential, and the reversal potential of GABAA-gated currents were left-shifted from 0 mV in control to -93 mV.CONCLUSION: BDNF with high concentration can make the reversal potential of GABAA-gated currents shifted leftward, and causes GABA to induce an excitatory effect through GABAA receptor.

Key words: Brain-derived neurotrophic factor, GABAA-receptor, Hippocampal neurons