链霉素对颈动脉窦压力感受器反射的抑制作用

Streptomycin inhibits carotid sinus baroreflex in anesthetized rats

在 2 3只隔离灌流颈动脉窦区的麻醉大鼠 ,观察了链霉素对颈动脉窦压力感受器反射的影响。结果如下 :(1)以链霉素 (10 0 μmol/L)隔离灌流大鼠左侧颈动脉窦区时 ,压力感受器反射机能曲线向左下方移位 ,曲线最大斜率 (PS)由 0 40± 0 0 1kPa降至 0 33± 0 0 1kPa (P <0 0 0 1) ,血压反射性下降 (reflexdecrease ,RD)幅度由 6 2 2±0 13kPa降至 5 0 2± 0 11kPa (P <0 0 0 1) ,阈压 (TP)、平衡压 (EP)和饱和压 (SP)则分别从 8 2 7± 0 2 5 ,12 71± 0 2 1和 2 4 41± 0 14kPa增至 10 33± 0 32 (P <0 0 1) ,13 33± 0 30 (P <0 0 1)和 2 6 11± 0 2 8kPa (P <0 0 1)。其中RD ,PS和TP的变化呈明显的剂量依赖性。 (2 )应用腺苷隔离灌流大鼠颈动脉窦区 ,引起颈动脉窦压力感受器反射的易化 ;在用链霉素预处理后 ,此易化效应不仅完全被阻断 ,且可使反射效应小于应用腺苷前的对照值。以上结果表明 ,链霉素对大鼠颈动脉窦压力感受器反射有明显的抑制作用。

The effect of streptomycin on the carotid baroreflex was examined in 23 anesthetized rats with isolated carotid sinus perfusion. The results obtained are as follows. (1) By perfusing the isolated carotid sinus with streptomycin (100 μmol/L) the functional curve of baroreflex was shifted to the right and upward with its peak slope (PS) decreasing from 0 40±0 01 to 0 33±0 01 kPa (P<0 001), and the reflex decrease in the mean arterial pressure (RD) was lowered from 6 22±0 13 to 5 02±0 11 kPa (P<0 001), while the threshold pressure (TP), equilibrium pressure (EP) and saturation pressure (SP) were signif icantly increased from 8 27±0 25 to 10 33±0 32 kPa (P<0 01), 12 71±0 21 to 13 33±0 30 kPa (P<0 01) and 24 41±0 14 to 26 11±0 28 kPa (P<0 01),respectively. Among the functional parameters of carotid baroreflex, the changes in RD, PS and TP induced by streptomycin were dose denpendent. (2) By perfusing the isolated carotid sinus with adenosine (125 μmol/L), carotid baroreflex was facilitated. Pretreatment with streptomycin (200 μmol/L) not only eliminated the facilitated effect of ado on carotid baroreflex but also caused a reflex decrease in MAP to a level lower than control. Taken together, it is suggested that streptomycin can markedly inhibit the carotid sinus baroreflex in anesthetized rats.