title: Identification of a B2-bradykinin receptor linked to phospholipase C and inhibition of dopamine stimulated cyclic AMP accumulation in the human astrocytoma cell line D384.
abstract: We have examined the activation of a phospholipase C signal transduction pathway by a B2-bradykinin receptor in the human astrocytoma cell line D384 and how this influences D1-dopamine receptor stimulated cyclic AMP accumulation. Addition of bradykinin to D384 cells resulted in a concentration-dependent (10(-11)-10(-6) M) increase in the accumulation of [3H]inositol phosphates and a similar concentration-dependent transient increase in specific [3H]beta-phorbol-12,13-dibutyrate binding which is indicative of translocation of protein kinase C from the cytosol to the membrane. Changes in intracellular Ca2+ of single cells, measured using the fluorescent indicator dye fura-2, indicated that bradykinin produced a rapid, but transient, increase in intracellular calcium. The Ca2+ response was largely independent of extracellular Ca2+ supporting the idea that receptor activation leads to mobilization of Ca2+ from intracellular stores. However, extracellular Ca2+ was required for a response to a rechallenge with bradykinin. The bradykinin B2-receptor agonist kallidin increased cytosolic Ca2+ in a similar manner to bradykinin. The Ca2+ response to bradykinin could be partially reduced in the presence of the B2-receptor antagonist [D-Arg0-Hyp,D-Phe7,beta-(2-Thienyl)-Ala5,8]-bradykinin, whereas the B1-receptor agonists (Des-Arg9]-bradykinin and [Des-Arg10]-kallidin were ineffective. Bradykinin was also found to attenuate dopamine stimulated cyclic AMP accumulation in D384 cells, at similar concentrations previously observed to stimulate the phospholipase C signal transduction pathway, in the presence of the phosphodiesterase inhibitor, rolipram. In contrast, no attenuation was observed in the presence of the phosphodiesterase inhibitor 1-isobutyl 3-methylxanthine, although the level of dopamine stimulated cyclic AMP observed was lower than in the presence of rolipram.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Cardiovascular Studies, University of Leeds, England.
authors.forename: A J
authors.initials: AJ
authors.lastname: Balmforth
authors.forename: F E
authors.initials: FE
authors.lastname: Parkinson
authors.forename: N
authors.initials: N
authors.lastname: Altiok
authors.forename: B B
authors.initials: BB
authors.lastname: Fredholm
mesh_terms: D001254:Astrocytoma / Q000378:metabolism*; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D004298:Dopamine / Q000494:pharmacology*; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D015759:Ionomycin / Q000494:pharmacology; D010703:Phorbol Esters / Q000378:metabolism; D018002:Receptors, Bradykinin; D017447:Receptors, Dopamine D1 / Q000187:drug effects / Q000378:metabolism; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D007295:Inositol Phosphates; D010703:Phorbol Esters; D018002:Receptors, Bradykinin; D017447:Receptors, Dopamine D1; D017981:Receptors, Neurotransmitter; D015759:Ionomycin; D000242:Cyclic AMP; D010738:Type C Phospholipases; D001920:Bradykinin; D002118:Calcium; D004298:Dopamine