Ca(2+)-activated outward-rectifier K+ channels and histamine release by rat gastric enterochromaffin-like cells.
Gastric enterochromaffin-like (ECL) cells were isolated from rat gastric fundic mucosa by Percoll density-gradient centrifugation and counter-flow elutriation. About 67% of cells in the purified cell suspension were ECL cells, which were reacted with anti-histidine decarboxylase antibody. A23187, a calcium ionophore, at 0.1-10 microM induced histamine release from ECL cell-rich suspension, indicating that the Ca2+ pathway is involved in the mechanism of histamine release from the ECL cells. A23187 at 5 microM significantly increased outward-rectifier cationic current in 62% of cells in the ECL cell-rich factions. A23187-sensitive cells showed acridine orange uptake. In single-channel recordings, a Ca(2+)-dependent outward-rectifier K+ channel of large conductance (146 +/- 22 picosiemens) was found in the cell that showed acridine orange uptake. The channel opened in a voltage-dependent manner at 0.1 microM of intracellular free Ca2+ concentration. These results may suggest that opening of the Ca(2+)-activated K+ channel is one of the steps involved in the mechanism of histamine release in ECL cells.
Sakai
H
H
Department of Pharmaceutical Physiology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Tabuchi
Y
Y
Kakinoki
B
B
Seike
H
H
Kumagai
S
S
Matsumoto
C
C
Takeguchi
N
N
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D005260:Female; D006636:Histamine Release / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000187:drug effects*
D015221:Potassium Channels; D000001:Calcimycin; D002118:Calcium