Visit our Expo - Redox and Inflammation signaling 2012

Session II : Receptor signaling and G proteins Poster II, 20
Angiotensin receptor signal transduction involving src and MAPK in rat nucleus tractus
solitarius
Takayuki Endoh and Takashi Suzuki
Department of Physiology, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba
261-8502, Japan. E-mail : tendoh@tdc.ac.jp
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. Voltagedependent
calcium channels (VDCCs) serve as crucial mediators of membrane excitability
and Ca2+-dependent functions. The purpose of this study was to investigate the effects of
Angiotensin (Ang) on VDCCs currents (ICa) in the NTS using patch-clamp recording
methods. An application of Ang caused facilitation of L-type ICa. AT1 receptors antagonist,
Losartan antagonized the Ang-induced facilitation of ICa. Intracellular dialysis of the Giprotein
antibody attenuated the Ang-induced facilitation of ICa. Both Src tyrosine kinase
inhibitor and mitogen activated protein kinase (MAPK) inhibitor attenuated the Ang-induced
facilitation of ICa. p38 MAPK inhibitor also attenuated the Ang-induced facilitation of ICa.
These results indicate that Ang facilitates L-type VDCCs via Gi-proteins involving Src
tyrosine kinase and p38 MAPK kinase mediated by AT1 receptors in NTS.
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