Ca2+ influx evoked by inositol-3,4,5,6-tetrakisphosphate in ras-transformed NIH/3T3 fibroblasts.
Infusion of inositol-3,4,5,6-tetrakisphosphate (Ins(3,4,5,6)P4) from the patch pipette into the cytoplasm, produced a biphasic intracellular free Ca2+ concentration ([Ca2+]i) increase in ras-transformed NIH/3T3 (DT) cells. The Ins(3,4,5,6)P4-induced increase in DT cells depended upon extracellular Ca2+, and was enhanced by membrane hyperpolarization. Identical [Ca2+]i increases were observed with intracellular application of inositol-1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) and inositol-1,3,4,6-tetrakisphosphate but not with inositol-1,2,4,5-tetrakisphosphate, inositol-1,4,5-trisphosphate or inositol-1,3,4,5,6-pentakisphosphate. Stimulation of DT cells with bradykinin increased the levels of Ins(3,4,5,6)P4 and Ins(1,3,4,5)P4. These results suggest that Ins(3,4,5,6)P4 may serve as a second messenger for continuous Ca2+ influx along with other tetrakisphosphates downstream from bradykinin receptors in DT cells.
Hashii
M
M
Department of Biophysics, Kanazawa University School of Medicine, Japan.
Hirata
M
M
Ozaki
S
S
Nozawa
Y
Y
Higashida
H
H
D016475:3T3 Cells; D000818:Animals; D001692:Biological Transport; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002461:Cell Line, Transformed; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D011905:Genes, ras; D007295:Inositol Phosphates / Q000494:pharmacology*; D008564:Membrane Potentials; D051379:Mice; D018002:Receptors, Bradykinin / Q000187:drug effects / Q000378:metabolism
D007295:Inositol Phosphates; D018002:Receptors, Bradykinin; C081652:inositol-3,4,5,6-tetrakisphosphate; D001920:Bradykinin; D002118:Calcium