The role of G proteins in the activity and mercury modulation of GABA-induced currents in rat neurons.
The role of G proteins in the functional modulation and potentiation by mercury chloride of the GABA(A) receptor-channel complex in rat dorsal root ganglion neurons was studied by using the whole-cell patch clamp technique. Stimulation of Gs proteins by application of GTP-gamma-S in the patch pipette or by incubation of neurons with cholera toxin reduced GABA-induced currents, suggesting modulation of GABA-induced currents via a Gs-protein-coupled pathway. GDP-beta-S in the pipette solution or pretreatment of dorsal root ganglion neurons with pertussis toxin suppressed GABA-induced currents, suggesting that basal Gi/Go-protein activity positively modulates the GABA(A) receptor-channel complex. Mercury chloride potentiation of GABA-activated currents was blocked by application of GTP-gamma-S in the patch pipette or by incubation of neurons with cholera toxin. Mercury chloride potentiation of GABA-activated currents was blocked by application of GDP-beta-S in the patch pipette or by incubation of neurons with pertussis toxin. G proteins, probably Gi/Go proteins, underlie the mercury chloride potentiation of GABA-induced currents.
Huang
C S
CS
Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611, USA.
Narahashi
T
T
D000818:Animals; D000831:Animals, Newborn; D002772:Cholera Toxin / Q000494:pharmacology; D004558:Electric Stimulation; D004594:Electrophysiology; D019204:GTP-Binding Proteins / Q000502:physiology*; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008628:Mercury / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D037342:Pertussis Toxin; D051381:Rats; D017207:Rats, Sprague-Dawley; D018079:Receptors, GABA / Q000187:drug effects / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007473:Ion Channels; D018079:Receptors, GABA; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D008628:Mercury