An ATP-dependent and inositol trisphosphate-sensitive Ca2+ pool linked with microfilaments of the parietal cell.
In digitonin-permeabilized parietal cells, myo-inositol 1,4,5-trisphosphate (Ins P3) or Ca2+ ionophore (A23187) increased the cytosolic Ca2+ concentration due to the intracellular Ca2+ release. Addition of ATP decreased the cytosolic Ca2+ concentration due to the rapid Ca2+ re-uptake into the same or similar pool which releases Ca2+ from a non-mitochondrial location (measured by quin2/AM and 45Ca2+). Cytochalasin B failed to increase the cytosolic Ca2+ concentration in response to Ins P3 or A23187 and even failed to decrease the cytosolic Ca2+ concentration in response to ATP. This implies that the ATP-dependent and Ins P3-sensitive Ca2+ pool is linked with the microfilaments of the parietal cell. In intact parietal cells, A23187 increased the amino[14C]pyrine accumulation (an index of acid secretion), that was independent of medium Ca2+. This increase of acid secretion was inhibited by the pretreatment with cytochalasin B. This suggests that medium Ca2+-independent acid secretion (by A23187) is regulated by the microfilaments. Therefore, there is a close relationship between the intracellular Ca2+ metabolism, microfilaments and acid secretion.
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism*; D004072:Digitonin / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism; D006168:Guinea Pigs; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000494:pharmacology*; D008297:Male; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism*; D013403:Sugar Phosphates / Q000494:pharmacology*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D000001:Calcimycin; D003571:Cytochalasin B; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D004072:Digitonin; D002118:Calcium