Jpn. J. Pharmacol. 84 (2), 140-145 (2000)


Intracellular Ca2+ Increase in Neuro-2A Cells and Rat Astrocytes Following Stimulation of Bradykinin B2 Receptor

Yuri Ikeda1, Akinori Ueno1, Hiroaki Naraba1, Norio Matsuki2 and Sachiko Oh-ishi1,*

1Department of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
2Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokyo University, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
*Corresponding author.╩╩Present address for correspondence: Kitasato Institute, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8642, Japan
FAX:+81-3-5791-6120, E-mail: oh-ishi@kitasato.or.jp


Abstract: 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.

Keywords: Bradykinin, Neuro-2A, Astrocyte, Intracellular Ca2+, Bradykinin B2 receptor


Copyrightę The Japanese Pharmacological Society 2000

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