Is rabbit CLCA1 related to the basolateral Ca2+ -dependent Cl- channel of gastric parietal cells?
An expression of mRNA coding the calcium-activated Cl- channel-1 (CLCA1) in rabbit gastric parietal cells was examined to verify the possibility that the CLCA1 mediates housekeeping Cl- channels in the basolateral membrane. In whole-cell voltage-clamp experiments of rabbit parietal cells, A23187 (2 microM), a Ca2+ ionophore, activated the basolateral Cl- channels. The partial cDNA fragment of rabbit CLCA1 could be amplified from the total RNA of tracheal epithelium. A Northern blot analysis showed that rabbit CLCA1 mRNA of 3.4 kb is highly expressed in the tracheal epithelium, but not in the gastric parietal cells. Even in a more sensitive detection of rabbit CLCA1 mRNA by RT-PCR, no signal could be observed in the gastric parietal cells. These results suggest that the CLCA1 protein may not be a subunit of the housekeeping Ca2+ -dependent Cl- channel in the basolateral membrane of rabbit gastric parietal cells.
Department of Pharmaceutical Physiology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Toyama, 930-0194 Japan. sakaihms.toyama-mpu.ac.jp.
H
H
Sakai
M
M
Ukai
A
A
Ikari
S
S
Asano
N
N
Tkeguchi
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D018118:Chloride Channels / Q000235:genetics / Q000502:physiology*; D008297:Male; D008969:Molecular Sequence Data; D010295:Parietal Cells, Gastric / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013270:Stomach / Q000166:cytology
D018118:Chloride Channels; D012333:RNA, Messenger; D002118:Calcium