Effects of electroacupuncture on pressor response to angiotensin-(1-7) by amino acid release in the rostral ventrolateral medulla

Unilateral microinjection of Angiotensin-(1-7)[Ang-(l-7)] into the rostral ventrolateral medulla (RVLM) of anesthetized rats caused an increase in mean arterial pressure (MAP) accompanied by an increased release of excitatory amino acid (EAA) glutamate. In contrast, microinjection of Ang779, a selective antagonist of Ang-(1-7) receptor, into the RVLM caused a decrease in MAP accompanied by a deceased release of EAA glutamate as well as an increased release of inhibitory amino acid (IAA) glycine, taurine and gamma-aminobutyric acid. After electroacupuncture (EA) stimulation at Zusanli(St.36) for 20 min, the above effects of Ang-(1-7) or Ang779 attenuated. These results suggest that attenuation of EA on the pressor effect of Ang-(I -7) or the depressor effect of Ang779 may be through regulating the corresponding amino acid neurotransmitter release in the RVLM.