Intracellular Ca2+ increase in neuro-2A cells and rat astrocytes following stimulation of bradykinin B2 receptor.
Murine neuroblastoma cell line Neuro-2A cells and rat brain astrocytes showed a dose-dependent increase in intracellular Ca2+ in response to bradykinin, when assessed by a single cell image analyzing system. The Ca2+ increase in Neuro-2A cells by bradykinin was also examined by a suspension fluorescent assay using fura-2 loading. The Ca2+ increase in both cases was suppressed by a bradykinin B2 receptor antagonist, Hoe 140, but not by a B1 receptor antagonist, des-Arg-Hoe 140, suggesting that the effect occurred via specific B2 receptor activation. RT-PCR for bradykinin B2 receptor mRNA showed that both Neuro-2A cells and the astrocytes expressed B2 receptor mRNA. Binding of [3H]bradykinin to Neuro-2A cells was assessed, and a specific binding constant of 0.75 nM was determined. Furthermore, the increase in [Ca2+]i by bradykinin could be caused by a release of Ca2+ from storage sites in the endoplasmic reticulum, since thapsigargin and U-73122 attenuated the effect of bradykinin in Neuro-2A as well as in astrocytes. These results indicate that both astrocytes and neuroblastoma Neuro-2A cells stimulated by bradykinin could express a bradykinin B2 receptor-mediated intracellular Ca2+ increase leading to signal transduction.
Ikeda
Y
Y
Department of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Ueno
A
A
Naraba
H
H
Matsuki
N
N
Oh-Ishi
S
S
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D051379:Mice; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin; D001920:Bradykinin; D002118:Calcium