[Amitriptyline facilitates the analgesic effect of adrenal medulla autograft in the lumbar subarachnoid space of the rat].

OBJECTIVES

To investigate the possible enhancement of analgesic effect induced by treatment with amitriptyline (AMI) after the autografting of suprarenal medulla into the subarachnoid lumbar space in the rat.

MATERIAL AND METHODS

Four experimental groups were formed (control + saline solution [SS]; control + AMI; transplant + SS and transplant + AMI). AMI (10 mg/kg i.p.) or SS was administered for 28 days after surgery. The tail-flick test, with baseline values taken before surgery, was used to measure threshold pain on days 1, 4, 7, 14, 21 and 28.

RESULTS

Suprarenal medullae transplantation afforded evident analgesic effect from day 1 to day 28. Analgesic effect was enhanced in transplanted rats treated with AMI from day 4 of treatment, with more evident effect on day 28. No analgesic effect per se was observed in the control group.

CONCLUSIONS

Our results confirm that grafting per se has an analgesic effect and that it can be improved by systematic treatment with AMI. These results suggest new possibilities for using suprarenal medulla grafts for pain.