Amino acids modulate the hypotensive effect of angiotensin-(1-7) at the caudal ventrolateral medulla in rats.

Department of Physiology and Pathophysiology, Shanghai Medical College of Fudan University (The former Shanghai Medical University), Shanghai 200032, China.

Regulatory peptides 2005 Jul 15

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The present experiment was designed to investigate the possible involvement of glutamate and taurine in the depressor response produced by angiotensin (Ang)-(1-7) at the caudal ventrolateral medulla (CVLM) in rats anesthetized with urethane and alpha-chloralose. Microinjection of Ang-(1-7) into the CVLM elicited a depressor response which was partially blocked by nonselective glutamate receptors antagonist kynurenic acid, whereas selective Ang-(1-7) antagonist Ang779 produced a pressor response which was significantly attenuated by taurine receptors antagonist 6-aminomethyl-3-methyl-4H-1,2,4-benzothiadiazine-1,1-dioxide. Release of glutamate and taurine in the CVLM was evaluated with microdialysis, and the contents of these amino acids were measured with high performance liquid chromatography-fluorescent detection. The depressor response to Ang-(1-7) was accompanied by an increased release of glutamate and a decrease of taurine at the CVLM, whereas the pressor response to Ang779 was associated with a decreased release of glutamate and an increase of taurine. These results suggest that Ang-(1-7) and its antagonist Ang779 modulate the release of glutamate and taurine at the CVLM, which in turn contributes at least in part to the blood pressure response to Ang-(1-7) and Ang779.

Citation

Jin Wang, Ying-Jie Peng, Da-Nian Zhu. Amino acids modulate the hypotensive effect of angiotensin-(1-7) at the caudal ventrolateral medulla in rats. Regulatory peptides. 2005 Jul 15;129(1-3):1-7