Wang J, Shen L L, Cao Y X, Sun Z J, Wang Q, Zhu D N
Department of Physiology, Medical College, Fudan University, Shanghai 200032.
Sheng Li Xue Bao. 2001 Feb;53(1):1-6.
The present study was undertaken to investigate the linkage between angiotensin-(1-7) [Ang-(1-7)] and the release of amino acid neurotransmitters in the the rostral ventrolateral medulla (RVLM) by techniques of microinjection, microdialysis combined with high performance liquid chromatography (HPLC)-fluorescent detection. Unilateral microinjection of Ang-(1-7) into the RVLM of anesthetized rats produced an increase in mean arterial pressure (MAP) accompanied by an increased release of glutamate (Glu). In contrast, microinjection of Ang779, a selective antagonist of Ang-(1-7) receptor, caused a decrease in MAP with a decreased release of Glu and an increased release of glycine, taurine and gamma-aminobutyric acid. The pressor effect of Ang-(1-7) and the depressor effect of Ang779 were in part blocked by corresponding antagonists of amino acid receptors. These results suggest that the pressor effect of Ang-(1-7) in the RVLM may be partially due to an increased release of Glu, whereas the depressor effect of Ang779 may be partially attributed to a decreased release of Glu and an increased release of inhibitory amino acid neurotransmitters.
本研究旨在通过微量注射、微透析结合高效液相色谱（HPLC）-荧光检测技术，探讨血管紧张素-（1-7）[Ang-（1-7）]与延髓头端腹外侧区（RVLM）氨基酸神经递质释放之间的联系。向麻醉大鼠的RVLM单侧微量注射Ang-（1-7）可使平均动脉压（MAP）升高，并伴有谷氨酸（Glu）释放增加。相反，注射Ang-（1-7）受体的选择性拮抗剂Ang779会导致MAP降低，Glu释放减少，甘氨酸、牛磺酸和γ-氨基丁酸释放增加。Ang-（1-7）的升压作用和Ang779的降压作用部分被相应的氨基酸受体拮抗剂阻断。这些结果表明，Ang-（1-7）在RVLM中的升压作用可能部分归因于Glu释放增加，而Ang779的降压作用可能部分归因于Glu释放减少和抑制性氨基酸神经递质释放增加。
