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Brain‐derived neutrotrophic factor (BDNF) binding is required for its receptor TrkB activation in the supraoptic nuclei (SON) following dehydration in the rat
Author(s) -
Carreno Flavia Regina,
Cunningham J Thomas
Publication year - 2010
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.24.1_supplement.1025.15
Subject(s) - tropomyosin receptor kinase b , phosphorylation , medicine , endocrinology , chemistry , brain derived neurotrophic factor , receptor , neurotrophic factors , biochemistry
Osmotic stimulation increases BDNF release and mRNA expression in the SON. Our previous studies indicate that the BDNF receptor TrkB is activated (indicated by phosphorylation status) in the SON following 48h water deprivation (WD). Phosphorylation of TrkB receptor can occur by either BDNF binding or transactivation. We tested the role of BDNF in phosphorylation of TrkB following WD by directly infusing the SON with a TrkB‐Fc fusion protein which prevents BDNF from binding to TrkB. Rats were instrumented with right SON cannula coupled to mini‐osmotic pumps (Alzet model 2004) prefilled with vehicle (0.9% saline) or TrkB‐Fc fusion protein (50ug/ul). Brain punches that contained the right (cannulated) and left (uncannulated) SON were collected separately from euhydrated controls and WD rats. Punches were subjected to Western Blot analysis for total TrkB full length and its phosphorylated TrkB levels. Densitometric measurements of the immunoreactive bands were normalized using GAPDH. In the left SON contralateral to the cannula, TrkB phosphorylation was significantly enhanced followed 48hWD (P<0.01; n=4). Analyis of the right SON receiving TrkB‐Fc showed that the TrkB receptor phosphorylation following WD was significantly attenuated (P<0.05; n=4). Our results show that following WD, TrkB phosphorylation in the SON is likely BDNF‐mediated. NIH R01 HL62579