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An ATP‐dependent and inositol trisphosphate‐sensitive Ca 2+ pool linked with microfilaments of the parietal cell
Author(s) -
Tsunoda Yasuhiro
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80010-2
Subject(s) - microfilament , inositol , cytosol , intracellular , secretion , digitonin , calcium , cytochalasin b , cytochalasin , ionophore , biochemistry , biology , chemistry , biophysics , cytoskeleton , cell , receptor , enzyme , organic chemistry
In digitonin‐permeabilized parietal cells, myo ‐inositol 1,4,5‐trisphosphate (Ins P 3 ) or Ca 2+ ionophore (A23187) increased the cytosolic Ca 2+ concentration due to the intracellular Ca 2+ release. Addition of ATP decreased the cytosolic Ca 2+ concentration due to the rapid Ca 2+ re‐uptake into the same or similar pool which releases Ca 2+ from a non‐mitochondrial location (measured by quin2/AM and 45 Ca 2+ ). Cytochalasin B failed to increase the cytosolic Ca 2+ concentration in response to Ins P 3 or A23187 and even failed to decrease the cytosolic Ca 2+ concentration in response to ATP. This implies that the ATP‐dependent and Ins P 3 ‐sensitive Ca 2+ pool is linked with the microfilaments of the parietal cell. In intact parietal cells, A23187 increased the amino[ 14 C]pyrine accumulation (an index of acid secretion), that was independent of medium Ca 2+ . This increase of acid secretion was inhibited by the pretreatment with cytochalasin B. This suggests that medium Ca 2+ ‐independent acid secretion (by A23187) is regulated by the microfilaments. Therefore, there is a close relationship between the intracellular Ca 2+ metabolism, microfilaments and acid secretion