GTP- and GDP-analogues modulate an inwardly rectifying chloride channel in cultured hippocampal neurons.
Three different GABA-insensitive Cl- channels could be resolved in cultured hippocampal neurons using the inside-out patch clamp configuration. The most commonly observed channel revealed an inward rectification with a chord conductance of 40 pS in symmetrical Cl- solutions at a membrane potential of -50 mV and had voltage sensitive gating kinetics. Channel openings were not observed in cell-attached patch, and after excision, several minutes of perfusion of the cytoplasmic side were required before detecting the first openings. The open state probability was increased by guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S 10(-4) M) and reduced by guanosine 5'-O-(2-thiophosphate) (GDP-beta-S 10(-4) M) suggesting its regulation by G proteins. This new identified chloride channel may account for the previously described voltage-sensitive, inward-rectifying whole cell Cl- current which was enhanced by adenosine in a pertussis toxin-sensitive manner.
Mager
R
R
Max-Planck Institute for Psychiatry, Department of Neuromorphology, Martinsried, Germany.
Ferroni
S
S
Schubert
P
P
D000818:Animals; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects* / Q000502:physiology*; D004594:Electrophysiology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013873:Thionucleotides / Q000494:pharmacology*
D018118:Chloride Channels; D013873:Thionucleotides; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C023427:guanosine 5'-O-(2-thiodiphosphate)