抄録
It is recognized that brain contains all the components of the renin-angiotensin systems (RAS). The nucleus tractus solitarius (NTS) is known to plays a major role in the regulation of cardiovascular, respiratory, gustatory, hepatic and swallowing functions. Voltage-dependent Ca2+ channels (VDCCs) serve as crucial mediators of membrane excitability and Ca2+-dependent functions such as neurotransmitter release, enzyme activity and gene expression. The purpose of this study was to investigate the effects of Angiotensin II (Ang II) on VDCCs currents (ICa) in the NTS using patch-clamp recording methods. An application of Ang IIcaused facilitation of L-type ICa. AT1 receptors antagonist, Losartan antagonized the Ang II-induced facilitation of ICa. Intracellular dialysis of the Gi-protein antibody attenuated the Ang II-induced facilitation of ICa. Both Src tyrosine kinase inhibitor and mitogen activated protein kinase (MAPK) inhibitor attenuated the Ang II-induced facilitation of ICa. These results indicate that Ang II facilitates L-type VDCCs via Gi-proteins involving Src tyrosine kinase and MAPK kinase mediated by AT1 receptors in NTS. [Jpn J Physiol 55 Suppl:S123 (2005)]
