Mice over-expressing galanin have elevated heat nociceptive threshold.

The neuropeptide galanin may have a role in modulation of nociceptive input at spinal level. Here we report that mice over-expressing galanin exhibit significant elevation of nociceptive threshold to thermal stimulation in comparison to wild-type mice as assessed by the tail flick and paw heat irradiation tests. No change in response to mechanical or cold stimulation was seen. The elevated heat nociceptive threshold in the galanin over-expressing mice was reversed by intrathecal application of the putative galanin receptor antagonist M-35, galanin-(1-12)-pro-bradykinin-(2-9). The results thus support that galanin has an inhibitory function in rodent spinal cord.