Prostaglandin E(2)-activated housekeeping Cl(-) channels in the basolateral membrane of rat gastric parietal cells.
Cl(-) channels in the basolateral membrane of parietal cells within isolated rat gastric glands were studied by the whole-cell patch-clamp technique. The membrane potential (E(m)) of non-stimulated parietal cells changed as a function of the basolateral extracellular Cl(-) concentration (46 mV per decade), but E(m) did not change significantly as a function of the K(+) concentration. The extracellular addition of prostaglandin E(2) (PGE(2); 10 microM) increased the whole-cell Cl(-) current. A bifunctional prostaglandin EP3 agonist/EP1 antagonist, 5(Z)-7-[(1S, 2S,3S,5R)-3-(trans-beta-styren)sulfonamido-6,6-dimethylbi cyclo-(3.1. 1)hept-2-yl]-5-heptenoic acid (ONO-NT-012; 10 microM), also increased the Cl(-) current. Basal Cl(-) currents and the PGE(2)- and ONO-NT-012-increased Cl(-) currents were voltage-independent and inhibited by a Cl(-) channel blocker, 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), at 500 microM. The single Cl(-) channel conductance was estimated to be 0.29 picosiemens (pS) by variance noise analysis. Both PGE(2) and ONO-NT-012 increased intracellular free Ca(2+) concentration in the fura-2-loaded parietal cell transiently. The present study has shown that housekeeping sub-pS Cl(-) channels are present in the basolateral membrane of rat parietal cell, and that the channels are regulated positively by PGE(2) via the EP3 receptor.
Ikari
A
A
Department of Pharmaceutical Physiology, Faculty of Pharmaceutical Sciences,Toyama Medical and Pharmaceutical University, Toyama, 930-0194, Japan.
Sakai
H
H
Tanaka
A
A
Ikeda
A
A
Inoue
K
K
Takeguchi
N
N
D000818:Animals; D016477:Artifacts; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015232:Dinoprostone / Q000502:physiology*; D007425:Intracellular Membranes / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D009994:Osmolar Concentration; D010295:Parietal Cells, Gastric / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D013343:Styrenes / Q000494:pharmacology
D001643:Bridged Bicyclo Compounds; D018118:Chloride Channels; C095324:ONO-NT 012; D013343:Styrenes; D015232:Dinoprostone