Galanin receptor 1 is expressed in a subpopulation of glutamatergic interneurons in the dorsal horn of the rat spinal cord
J. Comp. Neurol.. 2006-01-01; 499(3): 391-403
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1. J Comp Neurol. 2006 Nov 20;499(3):391-403.
Galanin receptor 1 is expressed in a subpopulation of glutamatergic interneurons
in the dorsal horn of the rat spinal cord.
Landry M(1), Bouali-Benazzouz R, André C, Shi TJ, Léger C, Nagy F, Hökfelt T.
(1)Inserm E 0358, Institut Francois Magendie, University of Bordeaux 2, F-33077
The 29/30 amino acid neuropeptide galanin has been implicated in pain processing
at the spinal level and local dorsal horn neurons expressing the Gal(1) receptor
may play a critical role. In order to determine the transmitter identity of these
neurons, we used immunohistochemistry and antibodies against the Gal(1) receptor
and the three vesicular glutamate transporters (VGLUTs), as well as in situ
hybridization, to explore a possible glutamatergic phenotype. Gal(1) protein,
which could not be demonstrated in Gal(1) knockout mice, colocalized with VGLUT2
protein, but not with glutamate decarboxylase, in many nerve endings in lamina
II. Moreover, Gal(1) and VGLUT2 transcripts were often found in the same cell
bodies in laminae I-IV. Gal(1)-protein and galanin-peptide showed an overlapping
distribution but were not colocalized. Gal(1) staining did not appear to be
affected by dorsal rhizotomy. Taken together, these findings provide strong
evidence that Gal(1) is a heteroreceptor expressed on excitatory glutamatergic
dorsal horn interneurons. Activation of such Gal(1) receptors may thus decrease
the inhibitory tone in the superficial dorsal horn, and possibly cause
PMID: 16998907 [Indexed for MEDLINE]