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Functional Effects of Endogenous BDNF in the Nucleus Tractus Solitarius (nTS)
Author(s) -
Clark Catharine Grace,
Kline David D.,
Kunze Diana L.,
Katz David M.,
Hasser Eileen M.
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.624.13
Subject(s) - tropomyosin receptor kinase b , solitary nucleus , medicine , endocrinology , microinjection , area postrema , solitary tract , chemistry , receptor , neuroscience , biology , neurotrophic factors
BDNF and its receptor, TrkB, are expressed in the nTS, the principal relay site for cardiorespiratory sensoryinput in the brainstem. Studies from our laboratories demonstrate BDNF plays a sympathoexcitatory role in vivo and modulates neurotransmission between visceral afferents and nTS neurons in vitro . To determine an endogenous role for BDNF in the nTS, we examined its expression and function in Sprague Dawley rats. Immunohistochemistry (IHC) was used to determine expression. Mean arterial pressure (MAP), heart rate (HR) and lumbar sympathetic nerve activity (LSNA) responses to BDNF manipulation in the nTS were recorded in vivo . IHC demonstrated BDNF was localized to the solitary tract and neuropil and co‐localized with Synaptophysin (synaptic terminal marker), but not with MAP2 (dendritic marker). Unilateral microinjection of BDNF (30 nl) dose dependently increased MAP, HR and LSNA. In the presence of AntiBDNF, a BDNF scavenging antibody, the response to BDNF was abolished. Bilateral nTS blockade of TrkB receptors using K252a (20μM; 90 nl) decreased MAP, HR and LSNA (Δ −6 ± 2 mmHg, −19 ± 5 bpm, −24.5 ± 7 % respectively), responses similar to AntiBDNF alone (10 μg/ml; 90 nl). Vehicle controls (aCSF or IgY) had no effect. These data suggest BDNF is localized at visceral afferent synapses and that autonomic regulation in the nTS is subject to endogenous modulation by BDNF, mediated by its receptor, TrkB. NS057398 (DMK)