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Reduced spinal cord sensitization to C‐fibre stimulation in mice over‐expressing galanin
Author(s) -
Grass Stefan,
Crawley Jacqueline N.,
Xu XiaoJun,
WiesenfeldHallin Zsuzsanna
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2003.02623.x
Subject(s) - galanin , sensitization , stimulation , nociception , neuropeptide , endocrinology , medicine , reflex , spinal cord , inhibitory postsynaptic potential , galanin receptor , neuroscience , receptor , biology
The neuropeptide galanin may have a role in spinal nociception. In this study, we examined the excitability of the flexor reflex and its sensitization by repetitive stimulation of nociceptive C‐fibres in anaesthetized mice that over‐express galanin. No difference was seen between over‐expressing galanin and wild‐type mice in the magnitude of the baseline flexor reflex. Repetitive conditioning stimulation of C‐fibres (10 stimuli at 1 Hz) produced a gradual increase in reflex magnitude during the conditioning stimulation (wind‐up), as well as an increase in spinal reflex excitability after the termination of the stimulus train (central sensitization) in wild‐type mice. Although the wind‐up did not differ between over‐expressing galanin and wild‐type mice, the magnitude of central sensitization was significantly reduced in the over‐expressing galanin mice (24 ± 13% peak increase compared with 164 ± 65% in the wild‐type). Intrathecal administration of M35, a galanin receptor antagonist, markedly enhanced central sensitization in over‐expressing galanin mice in association with C‐fibre conditioning stimulation, while having no effect in wild‐type mice. These results provide further electrophysiological evidence for an inhibitory function of galanin in modulation of central sensitization in response to C‐fibre stimulation.