Bradykinin inhibits cyclic AMP accumulation in D384-human astrocytoma cells via a calcium-dependent inhibition of adenylyl cyclase.
Bradykinin causes a concentration-dependent, transient rise in intracellular Ca2+ and a sustained inhibition of forskolin-, dopamine- and 5'-N-ethyl-carboxamidoadenosine (NECA)-stimulated cAMP accumulation in D384 astrocytoma cells. Chelation of intracellular calcium abolished bradykinin's inhibitory effect on cAMP accumulation. Chelating extracellular Ca2+ did not block the initial, but eliminated the sustained inhibition of cAMP accumulation. Increasing Ca2+ influx by calcium ionophore A23187 caused a concentration-dependent inhibition of stimulated cAMP accumulation. A hydroquinone derivative 2,5-di(tert-butyl)-1,4-benzohydroquinone (tBuBHQ), which inhibits microsomal Ca2+ sequestration, did not mimic the effect of bradykinin, although it increased [Ca2+]i even more than A23187 did. The inhibitory effect of bradykinin was not mediated by Ca2+/CaM-dependent stimulation of phosphodiesterase (PDE). Forskolin-stimulated adenylyl cyclase activity was inhibited by Ca2+ (10(-7) to 10(-3) M), both in ethyleneglycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) washed and native D384 plasma membranes. This effect was not altered by calmodulin (CaM) or CaM-antagonists. Bradykinin treatment, which attenuates cAMP accumulation in intact cells, did not do so in plasma membranes. These findings suggest that bradykinin-induced inhibition of cAMP formation in D384 cells requires mobilization of [Ca2+]i and subsequent entry of Ca2+ which directly interacts with a component of the adenylyl cyclase system.
Altiok
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N
Department of Pharmacology, Karolinska Institutet, Sweden.
Fredholm
B B
BB
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000241:Adenosine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000067956:Adenylyl Cyclase Inhibitors; D001254:Astrocytoma / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology*; D001932:Brain Neoplasms / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000378:metabolism; D005576:Colforsin / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004298:Dopamine / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors*; D011760:Pyrrolidinones / Q000494:pharmacology; D020889:Rolipram; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured
D000067956:Adenylyl Cyclase Inhibitors; D002147:Calmodulin; D006873:Hydroquinones; D009363:Neoplasm Proteins; D011760:Pyrrolidinones; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D005576:Colforsin; C019359:2,5-di-tert-butylhydroquinone; D019830:Adenosine-5'-(N-ethylcarboxamide); D000001:Calcimycin; D004533:Egtazic Acid; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D020889:Rolipram; D000241:Adenosine; D001920:Bradykinin; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine; D004298:Dopamine