论文部分内容阅读
测定动物脑内神经化学物质含量时所遇到的第一个问题,是如何处死动物才能使所测得的含量接近于正常生理水平。从断头到取出脑组织进行初步处理之间的时间往往长达数分钟,在此期间某些酶系统仍可不同程度地发挥作用。如某种神经化学物质的降解酶首先失活而合成酶继续工作,则死后含量将增高;反之,若合成酶首先失活,则含量将降低。已知脑内环核苷酸、r氨基丁酸等物质的水平都有很明显的“死后变化”,如不予克服,则神经化学测定的意义就将大大降低。减少死后变化的两个常用手段是迅速致冷或加温使酶失活,其中比较理想的是液氮冷冻或微波加温法。
The first question we encountered when determining the level of neurochemicals in the brain of an animal is how to kill the animal in order to bring the measured level closer to its normal physiological level. The time between decapitation and removal of brain tissue for initial treatment can often be as long as a few minutes, during which time certain enzyme systems can still function to varying degrees. If a neurochemical degrading enzyme is inactivated first and the synthetase continues to work, the content will increase after the death; conversely, if the synthase is first inactivated, the content will decrease. Known brain intracytoplasmic nucleotides, r aminobutyric acid and other substances have significant levels of “post-mortem changes”, if not overcome, the significance of neurochemical determination will be greatly reduced. Two common means of reducing post-mortem changes are deactivation of the enzyme by rapid cooling or warming, with liquid nitrogen freezing or microwave warming being preferred.