Dimethyl sulfoxide (DMSO) blocks GABA-induced current in rat dorsal root ganglion neurons.
The effects of dimethyl sulfoxide (DMSO) on gamma-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 microM 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 microM 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.
Nakahiro
M
M
National Hospital Shou-raii-soh, Nara, Japan.
Arakawa
O
O
Narahashi
T
T
Ukai
S
S
Kato
Y
Y
Nishinuma
K
K
Nishimura
T
T
D000818:Animals; D018118:Chloride Channels; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018756:GABA Antagonists; D005727:Ganglia, Spinal / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D018118:Chloride Channels; D018756:GABA Antagonists; D007473:Ion Channels; D008565:Membrane Proteins; D005680:gamma-Aminobutyric Acid; D004121:Dimethyl Sulfoxide