Galaninergic mechanisms at the spinal level: Focus on histochemical phenotyping
Neuropeptides. 2005-06-01; 39(3): 223-231
DOI: 10.1016/j.npep.2005.02.004
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1. Neuropeptides. 2005 Jun;39(3):223-31.
Galaninergic mechanisms at the spinal level: focus on histochemical phenotyping.
Landry M(1), Liu HX, Shi TJ, Brumovsky P, Nagy F, Hökfelt T.
Author information:
(1)INSERM E358, Institut Francois Magendie, Université Victor Segaleux Bordeaux
2, 146 rue Léo Saignat, 33077 Bordeaux, France.
The 29/30 amino acid neuropeptide galanin is present in a small population of DRG
neurons under normal condition but is strongly upregulated after nerve injury.
There is evidence that this upregulated galanin has trophic actions, for example
promoting neurite outgrowth as well as influencing pain processing. In fact, both
pro- and antinociceptive effects have been reported, probably relating to
activation of different receptors. It has been proposed that presynaptic GalR2
receptors are pro-nociceptive by enhancing release of excitatory transmitters in
the dorsal horn, and anti-nociceptive via an action on GalR1-positive
interneurons. These neurons have recently been shown to be glutamatergic. Several
other peptides and molecules are also regulated by nerve injury. Here we focus on
neuropeptide tyrosine (NPY), which is upregulated in parallel with galanin. We
review data reporting on coexistence between galanin and NPY and between these
two peptides and the two NPY receptors Y1 and Y2. The data show considerable
overlap, and it will be an important task to analyse how cross-talk between these
neuropeptides can influence pain processing. It is proposed that such cross-talk
can occur by release of peptides from DRGs neuron somata within dorsal root
ganglia. To what extent these mechanisms shown to exist in rodents also occur in
human is important, if one wants to discuss novel strategies for pain treatment
on the basis of these findings. So far information is limited, but it has been
demonstrated that galanin is expressed in DRGs and possibly also regulated.
DOI: 10.1016/j.npep.2005.02.004
PMID: 15893817 [Indexed for MEDLINE]