Effects of glycerol on the rat infraorbital nerve: an experimental study.

Glycerol was injected into the infraorbital canal of 12 rats to determine neurolytic effects on the peripheral trigeminal nerve. Saline and 90% ethanol were injected in control animals. One week after the injection, histopathological changes were noted in both glycerol and alcohol groups. In the former group, axonolysis and demyelination were restricted to the outer zone of the nerve bundles. Centrally located axons remained undamaged. A total destruction of all axons was found in the alcohol group. Four weeks after the injection in the glycerol group, small sized axons with thin myelin replaced damaged axons at the periphery of the bundle. No signs of regeneration were noted in the alcohol group. A possible mode of action of glycerol injected at the peripheral trigeminal nerve in relieving trigeminal neuralgia is described.