Methods of Tapping Canine Liquor Space to Assess Central Nervous System Toxicity Caused by Local Anesthetics

Abstract

It is convenient to tap cerebrospinal fluid (CSF) in dogs by means of lumber puncture under anesthesia and by means of aseptic surgical procedures after implantation of cannulas under anesthesia.

For behavioral studies, the surgical implantation of a facilitates Collison or Borison cannula into the epidural space or the lateral cerebral ventricle CSF sampling while causing no pain in dogs. In addition to a Collison cannula, a polyethylene tube (0.5 to 1 mm) leading from the lumbar subarachnoid space to the cisterna facilitates, without any pain, the perfusion of the liquor space after the recovery of the dog.

In anesthetized dogs, the CSF can be drained steadily and the perfusion system is quite stable. Furthermore, a perfusion from a cisternal cannula to a lumbar cannula and from an epicerebral cannula to the cisterna can also be achieved. The effect of drugs on the spinal cord can be studied. The perfusion of the spinal subarachnoid space alone is possible by performing a counterper-fusion of CSF from the lateral cerebral ventricle to the cisterna. A dog unit and simple surgical techniques are enough to carry out behavioral studies of sedation, sleep, and wakefulness caused by chemicals and drugs, including the pollutants. This article presents a summary of investigations of CNS toxicity caused by local anesthetics.

Key Words:

• canine CSF tapping
• local anesthetics
• toxicity