Regulation of intracellular pH by Ca2+-activated proton channel.
OBJECTIVE
We have characterized a membrane current associated with a decrease in pHi, which can be induced by either elevating intracellular calcium or extracellular application of methylmercury (a potent agent in elevating intracellular Ca(2+) concentration) in the alveolar macrophages bathing in the impermeant bilateral cesium aspartate solution.


RESULTS
Decreasing pHi and elevating [Ca(2+)]i profoundly enhanced, but H-7 (a broad-spectrum kinase inhibitor), W-7 (a selective calmodulin antagonist) and KN-93 (a calmodulin kinase II inhibitor) inhibited the currents.


CONCLUSIONS
These results indicate that rat alveolar macrophages possess a calcium-activated and pHi-sensitive proton channel which can be phosphorylated and activated by calmodulin kinase II.
Department of Cosmetic Science, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan. kuotsung@mail.chna.edu.tw
Tsung C
TC
Kuo
D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000378:metabolism*; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008767:Methylmercury Compounds / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017494:Proton Pumps / Q000378:metabolism; D011522:Protons; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology; D000096926:Benzenesulfonamides
D001596:Benzylamines; D002118:Calcium; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D007473:Ion Channels; D008767:Methylmercury Compounds; D047428:Protein Kinase Inhibitors; D017494:Proton Pumps; D011522:Protons; D013449:Sulfonamides; C072105:KN 93; D000096926:Benzenesulfonamides; C017967:W 7