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Two Olfactory Placode Derived Galanin Subpopulations: Luteinizing Hormone‐Releasing Hormone Neurones and Vomeronasal Cells
Author(s) -
Key S.,
Wray S.
Publication year - 2000
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1046/j.1365-2826.2000.00486.x
Subject(s) - vomeronasal organ , endocrinology , medicine , luteinizing hormone , galanin , hormone , prolactin , biology , hypothalamus , neuropeptide , receptor
In adult rodents, the peptide galanin is expressed in a subpopulation of hypothalamic luteinizing hormone‐releasing hormone (LHRH) neurones in an activity‐dependent manner. In this investigation, we examined whether galanin mRNA expression in mice was activated coincident with LHRH mRNA expression, as LHRH neurones differentiate from the olfactory placode. Using in situ hybridization, we show (i) that galanin mRNA is coexpressed in LHRH neurones prenatally, (ii) that there is a decrease in galanin mRNA expression relative to LHRH mRNA expression once LHRH mRNA positive/galanin mRNA positive neurones migrate out of the olfactory pit and into the nasal septum, and (iii) the presence of a novel population of galanin mRNA positive/LHRH mRNA negative expressing neurones in the olfactory pit/vomeronasal organ which do not migrate into the central nervous systenm (CNS). This study demonstrates that there are at least two populations of galanin mRNA expressing neurones arising from the olfactory placode; one that remains in nasal regions, is LHRH mRNA negative and whose function is unknown, and one which is coexpressed with LHRH. In addition, the temporal expression of galanin mRNA in LHRH cells indicates that initial activation and subsequent inactivation of galanin mRNA expression is independent of synaptic CNS connections.