Renin-angiotensin system is believed to have important roles in blood pressure regulation. Baro and chemoreceptor afferents project to the nucleus tractus solitarius (NTS) neurons. The expression of angiotensin II type 1 (AT₁) and 2 (AT₂) receptors in the NTS is confirmed. However the physiological roles of angiotensin II in NTS are not fully understood. We have previously reported that angiotensin II increased the frequency of spontaneous EPSCs in 33 % of the cells through the activation of AT₁ receptors and decreased it in 39 % of the cells through the activation of AT₂ receptors. In this report we aimed to reveal the effects of angiotensin II on tractus solitarius evoked EPSCs (eEPSCs) in the NTS by using a slice patch-clamp technique.
 Angiotensin II decreased the amplitude of eEPSCs in 56 % of the neurons and had no effect in 44 % of the cells. Under the presence of AT₁ receptor blocker (ARB) losartan (10 μM), angiotensin II increased the eEPSCs in 37 % of the cells and decreased it in 15 % of the cells. The other neurons (48 %) showed no responses.
These results suggest that the activation of AT₁ receptors induces opposite effects on spontaneous and synchronous release of glutamate.