Short-term effects of centrally administered galanin on the hyperosmotically stimulated expression of vasopressin in the rat hypothalamus: An in situ hybridization and immunohistochemistry study
Neuroendocrinology. 1995-01-01; 61(4): 393-404
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1. Neuroendocrinology. 1995 Apr;61(4):393-404.
Short-term effects of centrally administered galanin on the hyperosmotically
stimulated expression of vasopressin in the rat hypothalamus. An in situ
hybridization and immunohistochemistry study.
Landry M(1), Roche D, Calas A.
(1)Départment de Cytologie, CNRS URA 1488, Université P.-&-M.-Curie, Paris,
Galanin (GAL) is a 29-amino acid peptide that is present in the hypothalamic
magnocellular neurons of the rat supraoptic nucleus (SON) and paraventricular
nucleus (PVN). Since previous studies revealed a possible role of GAL in the
hydro-osmotic regulation, we have investigated the effects of GAL on the
vasopressin (AVP) mRNA content in the hypothalamic magnocellular neurons. We
demonstrated by in situ hybridization (ISH) and immunohistochemistry that 100
pmol of GAL or GAL fragment (1-16) injected into the lateral ventricle of
anesthetized dehydrated male rats induced a rapid (10 min time interval) decrease
of AVP mRNA and AVP content in the magnocellular cell bodies of SON and PVN.
These effects were quantified on an autoradiographic film and were also obvious
at the cellular level by using ISH with a radiolabeled or digoxigenin-labeled
oligonucleotide probe. Oxytocin mRNA content is not altered by the same injection
either in dehydrated male or lactating female rats. Under the same conditions of
lactation, AVP mRNA content is not modified and the i.c.v. injection of GAL has
no effect. GAL antagonist (M15) injection suppressed the GAL-induced decrease of
AVP mRNA in the dehydrated rats and increased AVP mRNA level in control rats. The
efficacy of M15 in antagonizing GAL effects on AVP mRNA suggests the involvement
of GAL receptors in the regulation of the vasopressinergic cell bodies. Moreover,
endogenous GAL seems to depress the AVP mRNA content of SON and PVN in vivo. The
possible origin of endogenous GAL and the mechanisms by which GAL can regulate
the AVP mRNA content are also discussed.
PMID: 7540263 [Indexed for MEDLINE]