Expression of Na+/HCO3- cotransporter and its role in pH regulation in mouse parotid acinar cells.
Ion transporters such as Na(+)/H(+) exchanger (NHE), Cl(-)/HCO(3)(-) exchanger (AE), and Na(+)/HCO(3)(-) cotransporter (NBC) are known to contribute to the intracellular pH (pH(i)) regulation during agonist-induced stimulation. This study examined the mechanisms for the pH(i) regulation in the mouse parotid and sublingual acinar cells using the fluorescent pH-sensitive probe, BCECF. The pH(i) recovery from agonist-induced acidification in the sublingual acinar cells was completely blocked by EIPA, a NHE inhibitor. However, the parotid acinar cells required DIDS, a NBC1 inhibitor, in addition to EIPA in order to block the pH(i) recovery. Moreover, RT-PCR analysis detected the expression of pancreatic NBC1 (pNBC1) only in the parotid acinar cells. These results provide strong evidence that the mechanisms for the pH(i) regulation are different in the two types of acinar cells, and pNBC1 contributes to pH(i) regulation in the parotid acinar cells, whereas NHE is likely to be the exclusive pH(i) regulator in the sublingual acinar cells.
Kim
Youn-Bae
YB
Department of Physiology, College of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul 110-749, Republic of Korea.
Yang
Byung Ho
BH
Piao
Zhang Gen
ZG
Oh
Seog Bae
SB
Kim
Joong Soo
JS
Park
Kyungpyo
K
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000378:metabolism; D000818:Animals; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D051379:Mice; D010306:Parotid Gland / Q000166:cytology* / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism; D027982:Sodium-Bicarbonate Symporters / Q000235:genetics / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D013361:Sublingual Gland / Q000166:cytology / Q000378:metabolism
D005452:Fluoresceins; D005456:Fluorescent Dyes; D020033:Protein Isoforms; D011976:Receptors, Muscarinic; C498899:Slc4a4 protein, mouse; D027982:Sodium-Bicarbonate Symporters; D017923:Sodium-Hydrogen Exchangers; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid