Ca(2+)- and nitric oxide-dependent stimulation of cyclic GMP synthesis in neuronal cell line induced by P2-purinergic/pyrimidinergic receptor.
The mechanism by which cyclic GMP synthesis is activated through a nucleotide receptor was studied in mouse neuroblastoma x rat glioma hybrid cells [108CC15 (NG 108-15)]. The transient increase in cyclic GMP level induced by ATP reached its maximum at 20 s and lasted for approximately 1 min. The maximal rise in cyclic GMP level achieved was highest for ATP and decreased in the following order: ATP = adenosine 5'(gamma-thio)triphosphate > UTP = 2-methylthio-ATP > ADP much greater than CTP, AMP, alpha,beta-methylene-ATP, 2'- and 3'-O-(4-benzoylbenzoyl)ATP. The EC50 of 1 +/- 0.2 microM for UTP was significantly lower than that for ATP (14 +/- 8 microM) and for all the other nucleotides tested. The rank order of potency is consistent with the pharmacology of a P2u receptor. At submaximal concentrations of the nucleotides ATP and UTP, the rise in cyclic GMP level was inhibited by suramin (IC50 = 40-60 microM) or the pyridoxal phosphate analogue pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (IC50 = 20-30 microM). Pretreatment of cells with the Ca2+ ionophore ionomycin or with 2,5-di(tert-butyl)-1,4-benzohydroquinone, an inhibitor of Ca(2+)-ATPase in the endoplasmic reticulum, a maneuver to deplete internal Ca2+ stores, suppressed the ATP- or UTP-induced stimulation of cyclic GMP synthesis. Similarly, loading of the cells with the Ca2+ chelator 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid inhibited cyclic GMP formation by ATP. Preincubation with forskolin to raise the cyclic AMP level potentiated the ATP-induced rise in cyclic GMP level by 60%.(ABSTRACT TRUNCATED AT 250 WORDS)
Reiser
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Physiologisch-chemisches Institut, Eberhard-Karls-Universität Tübingen, Germany.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism*; D005910:Glioma / Q000473:pathology; D006822:Hybrid Cells / Q000378:metabolism / Q000473:pathology; D015759:Ionomycin / Q000494:pharmacology; D051379:Mice; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013498:Suramin / Q000494:pharmacology; D014316:Tritium; D014407:Tumor Cells, Cultured
D000634:Aminoquinolines; D018048:Receptors, Purinergic P2; D014316:Tritium; D005576:Colforsin; D009569:Nitric Oxide; D015759:Ionomycin; D013498:Suramin; D000255:Adenosine Triphosphate; D006152:Cyclic GMP; C035739:Quin2; D001920:Bradykinin; D002118:Calcium