胍丁胺抑制麻醉大鼠颈动脉窦压力反射(英文)

目的:观察胍丁胺对颈动脉窦压力感受器反射的影响。方法:利用灌流左颈动脉窦方法,观察胍丁胺对麻醉大鼠压力反射机能参数的影响。结果:(1)胍丁胺1,5,10mmol/L均使颈动脉窦压力反射机能曲线向右上方移位,曲线最大斜率和反射性平均动脉压下降幅度均减小,提示胍丁胺对压力感受器反射有抑制作用;(2)预先应用咪唑啉受体(IR)和肾上腺素能α_2受体(α_2-AR)拮抗剂咪唑克生(idazox-an,0.1mmol/L),则可完全阻断胍丁胺5mmol/L的效应。预先应用α_2受体拮抗剂育亨宾(yohimbine,15μmol/L),则可部分阻断其效应;(3)预先应用NOS抑制剂L-NAME(500μmol/L),对胍丁胺的抑制作用无影响。结论:胍丁胺对颈动脉窦压力反射有抑制作用,并由咪唑啉受体和α_2受体介导。

Agmatine inhibits carotid sinus baroreflex in anesthetized rats

AIM: To study the effect of agmatine (Agm) on carotid sinus baroreflex. METHODS: The functional parameters of baroreflex were measured by perfusing the carotid sinus in anesthetized rats. RESULTS: (1) Agm 1, 5, and 10 mmol/L shifted the functional curve of carotid sinus baroreflex to the right and upwards in a concentration-dependent manner with a reduction in peak slope and a reflex decrease in mean arterial pressure, indicating that Agm exerted an inhibitory effect on the carotid baroreflex. (2) The inhibitory effect of Agm (5 mmol/L) on baroreflex was eliminated by pretreatment with idazoxan (Ida, 0.1 mmol/L), an alpha2-adrenoceptor (alpha2-AR) and imidazoline receptor (IR) antagonist, and partially blocked by yohimbine (Yoh, 15 micromol/L), a selective alpha2-AR antagonist. (3) NG-nitro-L-arginine methyl ester (L-NAME, 500 micromol/L), an NOS inhibitor, did not affect the inhibitory effect of Agm. CONCLUSION: Agm inhibits carotid baroreflex via IR and alpha2-AR.