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Hyperoxia decreases brain derived neurotrophic factor (BDNF) production in the carotid body and brainstem and catecholaminergic neurons in nucleus tractus solitarii (nTS).
Author(s) -
Mason Ariel Vanessa,
ChavezValdez Raul,
Johnson Sheree,
Gauda Estelle B
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.1043.1
Subject(s) - endocrinology , medicine , tropomyosin receptor kinase b , catecholaminergic cell groups , neurotrophic factors , brain derived neurotrophic factor , tyrosine hydroxylase , chemistry , brainstem , receptor , biology , dopamine
BDNF in the carotid body (CB) has trophic effects on the development of primary sensory afferents. Hyperoxic exposure (HYP) during early postnatal development causes hypoplasia of the CB, reduces sensory neurons, and ablates hypoxic chemosensitivity. We hypothesized that HYP would directly affect BDNF production in the CB and brainstem (BS) and tyrosine hydroxylase (TH) expression in the nTS. Methods Time‐dated SD rats were exposed to HYP (60% O 2 ) or (21% O 2 ) for 48h prior to delivery and for 7 or 14 days after delivery and then returned to 21% O 2 until postnatal day 9, 16 or 22 when the CB and BS were harvested and processed for gene (qRT‐PCR) and protein expression. Results HYP exposure for 7days reduced BDNF mRNA levels by 80% and 50% in the CB and BS, respectively (p=0.002) along with a 90% reduction in protein expression (p=0.04) in both tissues. HYP also up‐regulated p75 receptor gene expression in BS (1.6‐fold, p=0.002) without significant change in TrkB receptor. BS BDNF mRNA levels decreased from day 9 to 16 (p=0.04) but was not different between HYP and control animals at day 16. At day 22, there was a reduction in TH‐ir+ neurons and in TH protein levels (15%) in the nTS region of animals exposed to HYP, while no change in TH protein levels was observed in the locus coeruleus. Conclusion The reduction in TH+ neurons in the nTS in hyperoxic exposed animals may be linked to reduced BDNF production in the CB. Supported by NIH R01HL080725