Differential routing of coexisting neuropeptides in vasopressin neurons

Marc Landry, Evelyne Vila-Porcile, Tomas Hökfelt, André Calas
European Journal of Neuroscience. 2003-06-01; 17(11): 579-589
DOI: 10.1046/j.1460-9568.2003.02472.x

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1. Eur J Neurosci. 2003 Jun;17(11):579-89.

Differential routing of coexisting neuropeptides in vasopressin neurons.

Landry M(1), Vila-Porcile E, Hökfelt T, Calas A.

Author information:
(1)INSERM EPI 9914, Institut François Magendie, Université Victor Segalen,
Bordeaux, France.

Corrected and republished from
Eur J Neurosci. 2003 Feb;17(3):579-89.

The functional implications of intraneuronal coexistence of different
neuropeptides depend on their respective targeting to release sites. In the rat
hypothalamic magnocellular neurons, we investigated a possible differential
routing of the coexpressed galanin and vasopressin. The respective location of
proteins and messengers was assessed with double immunogold and in situ
hybridization combining confocal and electron microscope analysis. The various
populations of labelled granules were quantitatively compared in three
subcellular compartments: perikarya, local processes and posthypophyseal nerve
endings. Three subpopulations of granules were detected in all three
compartments, but their respective amount showed significant differences. Galanin
alone was immunolocalized in some secretory granules, vasopressin alone in
others, and both peptides in a third subpopulation of granules. The major part of
the granules containing vasopressin, either alone or in association with galanin,
is found in neurohypophyseal nerve endings. In contrast, galanin single-labelled
granules represent the most abundant population in dendritic processes, while
double-labelled granules are more numerous in perikarya. This indicates a
preferential distribution of the two peptides in the different compartments of
magnocellular neurons. Furthermore, galanin and vasopressin messenger RNAs were
detected at different domains of the endoplasmic reticulum, suggesting that
translation might also occur at different locations, thus leading to partial
segregation of galanin and vasopressin cargoes between two populations of
secretory granules. The present study provides, for the first time in mammals,
evidence suggesting that galanin and vasopressin are only partly copackaged and
undergo a preferential targeting toward dendrites or neurohypophysis, suggesting
different functions, autocrine/paracrine and endocrine, respectively.

DOI: 10.1046/j.1460-9568.2003.02472.x
PMID: 12814355 [Indexed for MEDLINE]

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