Cyclic AMP inhibits inositol polyphosphate production and calcium mobilization in neuroblastoma X glioma NG108-15 cells.
In the neuroblastoma X glioma hybrid cell line NG108-15, bradykinin (BK) receptor stimulation induced a rapid and concentration-dependent rise in cytosolic free Ca2+ levels, as measured with the Ca2(+)-sensitive fluorescent dye fura-2. The Ca2+ transient was present in the absence of extracellular Ca2+ and was associated with a concentration-dependent production of inositol phosphates, particularly inositol trisphosphate (InsP3). Pretreatment of intact NG108-15 cells with forskolin or dibutyryl-cAMP plus isobutylmethylxanthine reduced BK-stimulated InsP3 production and the increase in cytosolic free Ca2+. Membranes prepared from forskolin- and [3H]inositol-pretreated NG108-15 cells also showed a diminished production of InsP3 elicited by guanosine 5'-[gamma-thio]triphosphate, NaF, or BK plus GTP. On the other hand, the Ca2+ sensitivity of membrane-associated phosphoinositide-specific phospholipase C (PI-PLC) was unaffected by forskolin pretreatment of intact NG108-15 cells. Collectively, these results suggest that A-kinase may inhibit receptor-mediated and postreceptor stimulation of PI-PLC in neuron-like cells, perhaps by impairing the coupling between a guanine nucleotide-binding protein and PI-PLC.
Campbell
M D
MD
Department of Animal Biology, University of Pennsylvania, Philadelphia 19104-6046.
Subramaniam
S
S
Kotlikoff
M I
MI
Williamson
J R
JR
Fluharty
S J
SJ
D000262:Adenylyl Cyclases / Q000378:metabolism; D001920:Bradykinin / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D006822:Hybrid Cells / Q000187:drug effects; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
D005576:Colforsin; D003994:Bucladesine; D015544:Inositol 1,4,5-Trisphosphate; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D001920:Bradykinin; D002118:Calcium