Picrotoxin对家兔急性低氧循环反应的效应

THE EFFECTS OF PICROTOXIN ON THE CIRCULATORY RESPONSE TO ACUTE HYPOXIA IN RABBITS

本研究观察了Picrotoxin对家兔急性低氧循环反应的效应，从而探讨GABA在家兔低氧循环反应中的作用。动物麻醉制动，经人工呼吸机吸入11％低氧混合气。动物分两组，对照组（n＝11）静脉注射盐水（1ml／kg），实验组（n＝8）静脉注射Picrotoxin（1mg／1ml／kg）。对照组的动物低氧期间HR和MAP明显降低，停止低氧5－10分恢复；实验组的动物低氧期间HR明显低于对照组，MAP低氧早期升高，后期维持在对照水平。本结果说明Picrtoxin有效阻断了低氧引起的MAP下降，证明GABA参与了家兔急性低氧循环反应。文中对有关机制进行了讨论。

Brain r-aminobutyric acid(GABA) may modulate the circulatory response to hypoxia.The effects of the venous injection of GABA antagonist on the circulatory response to acute hypoxia (simulated altitude 6500M) were studied in rabbits anesthetized with urethan and chloralose,immobilized with gallamine triethiodide and ventilated artificially. The animals were divided into two groups:the control group with the venous injection of physiolgical saline(1ml/kg) and the experimental group with the venous inijection of picrotoxin (1mg /1ml/kg). The results in dicated that the heart rate and the mean arterial pressure in the control group presented significant decrease during hypoxia, then reached to the control level at 5-10 min after normoxia,the heart rate in the experimental group presented remarkably significant decrease than the control group during hypoxia, but the mean arterial pressure in the experimental group presented significant increase during early period of hypoxia,and then maintained the control level. These results suggest that the decrease in the mean arterial pressure to hypoxia was in part mediated through the depressant effect of GABA on the central nervous system.