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TrkB pathway may mediate NR1 phosphorylation in the supraoptic nuclei following dehydration in the rat
Author(s) -
Carreño Flávia Regina,
Ji Lisa,
Cunningham J Thomas
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1015.7
Subject(s) - tropomyosin receptor kinase b , vasopressin , supraoptic nucleus , phosphorylation , medicine , endocrinology , western blot , chemistry , dehydration , stimulation , receptor , biology , microbiology and biotechnology , neurotrophic factors , biochemistry , gene
Osmotic stimulation increases brain derived neutrophic factor (BDNF) release and mRNA expression in the supraoptic nucleus (SON). However, the significance of BDNF and its receptor TrkB in the regulation of vasopressin secretion remains to be determined. Brain punches that contained the SON were collected from euhydrated controls, 48 h water deprived rats (48WD), and two other groups of rats were water deprived for 46 h followed by access to water for 2 (2hR) or 4 h (4hR). Punches were homogenized and the total lysate was subjected to Western Blot analysis for TrkB, NR1 and NR2 subunits and phosphorylated forms of TrkB (pTrkBY515) and NR1 (pNR1) expression. Densitometric measurements of the immunoreactive bands were normalized using GAPDH. Although no changes were observed for TrkB, NR1, and NR2 expression, pTrkBY515 and pNR1 expression were significantly increased (P<0.01) in the SON of 48hWD animals compared to euhydrated animals. NR2 phosphorylation was not affected. Accesses to water for 2 h reduced pTrkBY515 without effecting pNR1. Finally, 4 h rehydration decreased pTrkBY515 to control levels and reduced pNR1 expression. In conclusion, our data suggest that increased TrkB phosphorylation in the SON following dehydration may play a role in the upstream phosphorylation of NR1. TrkB signaling in the SON may affect cellular excitability and vasopressin release during progressive dehydration. NIH R01, HL62579