Objective：To investigate the mechanism of the reversal effect of acupuncture on the fall of blood pressure induced by angiotensin （1-7）[Ang-（1 7）] in the caudal ventrolateral medulla （CVLM） of rats. Methods： Ang-（1-7） and its selective receptor antagonist （DAla7）, Ang（1-7） and Ang（779） were microinjected into the CVLM respectively to induce the change of blood pressure, during which, the concentrations of amino acid neurotransmitters were detected by means of microdialysis and high performance liquid chromatography （HPLC）combined with fluorescent detector, on the other hand, the effects of electro-acupuncture （EA） on the level of blood pressure and the concentrations of amino acid neurotransmitters were also observed. Results： Unilateral microinjection of Ang（1 7） into the CVLM could decrease the blood pressure （BP）, which was accompanied by an increase in the release of Glu and a decrease in the release of Tau in the same site; Whereas microinjection of Ang-779 into the CVLM could elevate BP, which was accompanied by a decrease in the release of Glu and an increase in the release of Tau; EA at acupoint Zusanli （ST 36） for 20 min could inhibit the fall of blood pressure induced by microinjection of Ang-（1-7） into the CVLM and the elevation of blood pressure induced by microinjection of Ang-779 into the CVLM, and in the meantime, it could inhibit the changes of the release of Glu and Tau induced by microinjection of Ang-（1-7） and Ang-779 into the CVLM. Conclusion： The reversal effect of EA on the fall or elevation of blood pressure induced by microinjection of Ang-（1-7） or Ang-779 into the CVLM might be related to the changes of Glu and Tau release.
