Abstract:

Objective    To investigate the mechanism of γ-aminobutyric acid(GABA) receptors modulating glutamate receptors. Methods    Whole-cell patch-clamp recording was used to detect GABA and glutamate receptors-mediated whole-cell currents（IGABA，IGlu） in cultured rat hippocampal neurons. The molecular mechanism of GABA receptors modulating glutamate receptors was studied, using bicuculline（Bic） to inhibit IGABA, and SO2-4 or gluconate- to replace Cl-. Results      Co-application of GABA and glutamate-induced IGABA+Glu was less than expected summation of currents IGABA and IGlu, which were induced by application of GABA and glutamate respectively, and the difference was reduced with the increase of concentrations. GABA rapidly and reversibly inhibited IGlu activated by 30μmol/L of glutamate in a concentration-dependent manner.  And the inhibition could be reversed by bicuculline, SO2-4 and gluconate-. Conclusion    GABAA receptors can down-regulate glutamate receptors, and the mechanism may be related to Cl-permeability.

Key words: Receptors， GABA； Receptors， Glu； Patch-clamp techniques