EFFECTS OF DIZOCILPINE ON AUTOTOMY BEHAVIOR AFTER NERVE-SECTION IN MICE

The effects of acute administration of dizocilpine (MK-801) at differe nt perioperative times on autotomy behavior after sciatic and saphenou s nerve transection were studied in the mouse. Control mice developed a severe self-mutilating behavior starting 1-3 days postoperation and reaching a maximum by 11 days. Mice injected with a single dose of diz ocilpine (0.4 mg/kg i.p.) before operation, the Ist or 3rd postoperati ve day autotomized significantly less than controls. An l-wk treatment with the same dose once a day did not show further benefit. A single administration of dizocilpine the 5th day after surgery slightly halte d further progression of autotomy. Dizocilpine did not have any delete rious effect on normal peripheral nerve function. These results sugges t that NMDA receptor blockade prevents development of hyperalgesia and neuropathic pain after peripheral nerve injuries but only when it is administered before or during the first 3 days after injury.