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Expression of tyrosine hydroxylase and vasopressin in magnocellular neurons of salt‐loaded aged rats
Author(s) -
Marsais F.,
Parmentier C.,
Terao E.,
Taxi J.,
Calas A.
Publication year - 2002
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.10018
Subject(s) - tyrosine hydroxylase , vasopressin , catecholaminergic , supraoptic nucleus , magnocellular cell , hypothalamus , endocrinology , medicine , biology , nucleus , catecholaminergic cell groups , neuropeptide , stimulation , microbiology and biotechnology , dopamine , receptor
Tyrosine hydroxylase (TH) is expressed in catecholaminergic neurons. However, under certain conditions it is also ectopically expressed in magnocellular neurons of the hypothalamus. To test the hypothesis that this expression of TH is related to the cellular activation of these neurons and/or to the vasopressin (VP) expression, we studied the expression of both TH and VP in control and salt‐loaded aged rats. Our results demonstrate that aged rats show a marked TH expression in VP cells which is further increased by osmotic stimulation in the absence of increase in VP synthesis in the supraoptic nucleus. The presence of TH‐immunopositive dendritic swellings in the ventral part of this nucleus reveals the high state of plasticity of these neurons. Furthermore, the lack of several actors of catecholamine biosynthesis in these neurons suggests a different role for TH. This study further demonstrates an ectopic expression of TH in hypothalamic neurons of aged rats and a TH expression linked to the activation of VP neurons but unrelated to VP synthesis. Microsc. Res. Tech. 56:81–91, 2002. © 2002 Wiley‐Liss, Inc.