Abstract
Mice and other small animals are often used in experimental studies on central nervous disorders. If the intrathecal administration of certain sub-stances is required in such experiments, the substances are usually adminis-tered by cisternal puncture under general anesthesia. In work on metabolic aspects of diseases, however, general anesthesia is disadvantageous since it influences cerebral metabolic conditions.
The present authors thus developed a technique for intrathecal adminis-tration by lumbar puncture in the mouse under local anesthesia. Although it may appear that correct positioning of a mouse could be difficult under local anesthesia, the authors were able to ensure a satisfactory posture by pulling the bilateral ears and tail gently in the craniocaudal direction. In order to puncture the mid-point of the spinous processes accurately in the mouse, we observed the spinous processes directly through a lumbosacral incision in the skin.
In order to test the reliability of our technique, trypan blue and 5% glucose were administered to mice intrathecally.
Based on macroautograms obtained at 30 min after intrathecal admin-istration of 25 μl of trypan blue, the intrathecal injection of trypan blue by our technique was judged to be successful in 95% of the twenty mice.
Twenty-five μl of 5% glucose was administered intrathecally to mice and the intracerebral water content was estimated at 10, 20, 30, 40, 50, 60min after the administration following decapitation.
No marked change in intracerebral water content was observed at 10min after the intrathecal administration, but at 20min a significant rise in water content was found (p<0.05). The water content tended to decrease there-after and at 30min it dropped to the pre-administration level.
It is considered therefore that the intrathecally administered glucose affected the intracerebral water content in some definite way, thereby demon-strating the reliability of our method.
Compared to cisternal puncture, the present technique for lumbar punc-ture offers several advantages.
1) It can be carried out under lacal anesthesia.
2) Practically, it is a simpler procedure than cisternal puncture.
3) It is reliable, giving a high success rate of over 95%.
