Possible involvement of GTP-binding proteins in the deactivation of an inwardly rectifying K+ current in enterocytes isolated from guinea-pig small intestine.
The possible regulation of guinea pig enterocyte ion channels by GTP-binding proteins has been investigated by using the whole-cell recording mode of the patch-clamp technique and non-hydrolysable analogues of GTP. The main K+ currents in these cells are mediated by inwardly-rectifying K+ channels. Intracellular dialysis with hydrolysis-resistant GTP analogues leads to the deactivation of the inward K+ currents. Non-hydrolysable analogues of ATP or GDP were without effect. The effect occurs after a lag phase of 2 to 7 min, suggesting a multistep mechanism. Cl currents were not affected by any of the nucleotide analogues. It is suggested that inwardly-rectifying K+ currents are deactivated by a G-protein-dependent process.
Fargon
F
F
AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, UK.
McNaughton
P A
PA
Sepúlveda
F V
FV
D000818:Animals; D002712:Chlorides / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*
D002712:Chlorides; D007473:Ion Channels; D015221:Potassium Channels; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins