Previous studies from our laboratory have shown that the pressor response to intracerebroventricular (icv) administered ANG II in normotensive rats or spontaneously hypertensive rats (SHRs) is attenuated by increased central H₂O₂ concentration, produced either by direct H₂O₂ icv injection or by increased endogenous H₂O₂ centrally in response to local catalase inhibition with 3-amino-1,2,4-triazole (ATZ). In the present study, we evaluated the effects of ATZ administered peripherally on arterial pressure and sympathetic and angiotensinergic activity in SHRs. Male SHRs weighing 280–330 g were used. Mean arterial pressure (MAP) and heart rate (HR) were recorded in conscious freely moving SHRs. Acute intravenous injection of ATZ (300 mg/kg of body weight) did not modify MAP and HR during the next 4 h, however, the treatment with ATZ (300 mg/kg of body weight twice per day) for 3 days reduced MAP (144 ± 6, vs. saline, 183 ± 13 mmHg), without changing HR. Intravenous hexamethonium (ganglionic blocker) produced a smaller decrease in MAP 4 h after ATZ (−25 ± 3, vs saline −38 ± 4 mmHg). Losartan (angiotensinergic AT₁ receptor blocker) produced a significant depressor response 4 h after ATZ (−22 ± 4, vs. saline: −2 ± 4 mmHg) and in 3-day ATZ treated SHRs (−25 ± 5, vs. saline: −9 ± 4 mmHg). The results suggest that the treatment with ATZ reduces sympathetic activity in SHRs and simultaneously increases angiotensinergic activity.

我们实验室之前的研究表明，正常血压大鼠或自发性高血压大鼠 (SHR) 对侧脑室 (icv) 给予 ANG II 的升压反应会因直接 H ₂ O ₂ icv 注射产生的中心 H ₂ O _2浓度增加而减弱或通过增加内源性 H ₂ O ₂来响应 3-氨基-1,2,4-三唑 (ATZ) 的局部过氧化氢酶抑制。在本研究中，我们评估了外周给药 ATZ 对 SHR 中动脉压以及交感神经和血管紧张素能活性的影响。使用体重为 280-330 克的雄性 SHR。在有意识、自由活动的 SHR 中记录平均动脉压(MAP) 和心率 (HR)。急性静脉注射ATZ（300 mg/kg 体重）在接下来的 4 小时内没有改变 MAP 和 HR，然而，用 ATZ（300 mg/kg 体重每天两次）治疗 3 天降低了 MAP（ 144 ± 6，对比生理盐水，183 ± 13 mmHg），不改变 HR。ATZ 后 4 小时静脉注射六甲铵（神经节阻滞剂）可使 MAP 产生较小的下降（−25 ± 3，与生理盐水 -38 ± 4 mmHg）。氯沙坦（血管紧张素 AT ₁受体阻滞剂）在 ATZ 后 4 小时（-22 ± 4，对比生理盐水：-2 ± 4 mmHg）和 3 天 ATZ 治疗的 SHR（-25 ± 5，对比生理盐水）产生显着的抑制反应：−9±4毫米汞柱）。结果表明，ATZ 治疗可降低 SHR 的交感神经活性，同时增加血管紧张素能活性。