Behavioral evaluation of symptoms of allodynia and hyperalgesia in rats with a tibial and sural nerve transection.

Described here are the effects over time of a tibial and sural nerve transection model, two branches of sciatic nerve in rats, as a model of neuropathic pain syndromes in man. In two series of experiments conducted over a period of 56 days, it was demonstrated that transection of 2 of the 3 branches of the sciaticus resulted in a reproducible series of sensory deficits including cold, chemical, and mechanical allodynia and mechanical hyperalgesia. Most of the behavioral measurements started at day 3 after surgery and reached maximum effect within 1-2 weeks. The effects remained present over the 56 days measurement period. Nothing was seen on the thermal allodynia or on spontaneous pain behavioral tests. These results indicate that cutting of tibial and sural nerves results in a reproducible model of neuropathic pain syndromes with clear measurements of allodynia and hyperalgesia, and thus can be used for research and drug testing. [ABSTRACT FROM AUTHOR]