Dimethyl sulfoxide (DMSO) blocks GABA-induced current in rat dorsal root ganglion neurons

Abstract

The effects of dimethyl sulfoxide (DMSO) on γ-aminobutyric acid (GABA)-induced Cl − currents of rat dorsal root ganglion neurons in primary culture were studied by the whole-cell patch-clamp technique. Bath application of 5 μM GABA evoked sustained inward and outward currents at membrane potentials of −60 mV and +30 mV, respectively, when the external and internal solutions both contained 142 mM Cl −. DMSO at concentrations of 0.3–3% (v/v) caused a dose-dependent inhibition of the inward current induced by 5 μM GABA at −60 mV. DMSO at 3% inhibited the GABA-induced inward and outward currents at −60 mV and +30 mV to similar extents (54% and 53% of the control, respectively), but the time-course of inhibition of the outward current at +30 mV was much faster than that of the inward current at −60 mV. These results suggest that DMSO suppressed the currents by interacting with GABA receptor-Cl − channel complex protein rather than by affecting the lipid-bilayer of the cell membrane.