清醒犬脑内微量注射药物的方法

对清醒犬脑内微量注射实验用三套不锈钢管,即导向管、注射外管和注射管,外径分别为0.75、0.45、和0.25mm。实验前给麻醉犬皮质内埋藏导向管,测定出从导向管顶端至注射核团的深度,导向管周围用有机玻璃圈和牙托粉加固。术后隔3～5d进行实验。首先拔出导向管内蕊,将带有蕊子的注射外管插至定位的中枢核团。然后拔出注射外管内蕊,插入充满药液的注射管进行微量注射。实验结束时拔出注射管和注射外管,放入导向管内蕊,以便再次实验。本方法结合清醒犬慢性实验的特点,加固了导向管;用三套管的方法保证了注射管的通畅,减少了脑内组织增生、感染等并发症,能使实验持续2～3周。

A METHOD OF MICROINJECTION OF DRUGS INTO BRAIN IN CONSCIOUS DOG

An improved method of microinjection of drugs into the local area of brain in conscious dog is described. The injection tubing system consists of three stainless steel cannula: A fixed guide cannula, a secondary guide cannula, and an injector cannula, the outer diameters being 0.75, 0.45 and 0.25 mm respectively. Firstly, the dog was anesthetized and an aseptic operation was performed to implant the fixed guide cannula. The head of the dog was mounted on the stereotaxic instrument and a hole was drilled on the skull. The fixed guide cannula was then implanted into the cortex, its direction aiming at the subcortical nucleus expected. The guide cannula was then fixed into a plastic ring which was previously mounted on the skull with screws and dental cement. After surgery, a stylet was placed into the cannula. Three to five days later, when the dog had been recovered, micoinjeo-tion of drugs was carried out in conscious animal. The stylet was taken out and a secondary guide cannula was placed into the fixed guide cannula. The length of the secondary guide cannula was predetermined so that its tip just reached the expected nucleus. The stylet of the secondary guide was taken out and an injector cannula was placed into it. The injector cannula was filled with drug solution and connected to a microinjection driver. A minute amount of drug could then be injected into the local area. After the experimental observation, the injector and secondary guide cannulae were withdrawn and the stylet was again placed into thefixed guide cannula. Microinjection procedures could be repeated on every other day.