Predominant expression of type-VI adenylate cyclase in C6-2B rat glioma cells may account for inhibition of cyclic AMP accumulation by calcium.
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ABSTRACT: In C6-2B cells, agonist-stimulated cyclic AMP accumulation is inhibited when the cytosolic Ca2+ concentration is increased. We now demonstrate that in C6-2B cells: (i) the early kinetics of the cyclic AMP inhibition by substance K (t1/2 = 35 s) and thapsigargin (t1/2 = 1.6 min) closely mimic the kinetics of the cytosolic Ca2+ increase evoked by either agent (t1/2 = 25 s and 1.5 min respectively); (ii) the Ca2+ rise and cyclic AMP inhibition by substance K or thapsigargin are similarly affected in EGTA-containing medium; (iii) PCR detects type-III and type-VI adenylate cyclase cDNAs, and RNAase protection assays show that the mRNA for type-VI adenylate cyclase, an isoform inhibitable by submicromolar Ca2+ concentrations, is the predominant species, strongly suggesting that type-VI adenylate cyclase is probably the target molecule for Ca(2+)-mediated inhibition of cyclic AMP accumulation.
SUBMITTER: Debernardi MA
PROVIDER: S-EPMC1134362 | biostudies-other | 1993 Jul
REPOSITORIES: biostudies-other
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