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Regulation of brain‐derived neurotrophic factor transcripts by neuronal activation in rat hypothalamic neurons
Author(s) -
Marmigère Frédéric,
Rage Florence,
TapiaArancibia Lucia
Publication year - 2001
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.1230
Subject(s) - brain derived neurotrophic factor , glutamate receptor , neurotrophic factors , biology , medicine , exon , endocrinology , trk receptor , tropomyosin receptor kinase b , neurotrophin , messenger rna , receptor , microbiology and biotechnology , gene , genetics
Brain‐derived neurotrophic factor (BDNF) belongs to the neurotrophin family and regulates the survival, differentiation, and maintenance of function in different neuronal populations. BDNF is strongly expressed in hypothalamic neurons, where it exerts long‐ or short‐lasting actions. Because glutamate has been associated with regulations of hypothalamic hormones, we examined the regulation of the four promoters of the BDNF gene by glutamate in fetal hypothalamic neurons. The expression levels of BDNF transcripts were investigated using semiquantitative RT‐PCR. BDNF protein was determined by enzyme immunoassay, and BDNF and Trk B (BDNF receptor) gene variations were determined by RNAse protection assay. By RT‐PCR, we showed that, under basal conditions, BDNF transcripts from exons I, II, and III but not from IV were expressed in the hypothalamic neurons. Glutamate increased expression of both the protein and the four transcripts via N‐methyl‐D‐aspartate receptors, with maximal stimulations after 3 hr of application for exon I and II mRNAs and after 1 hr for exon III and IV mRNAs. Actinomycin D blocked the increase of all transcripts, whereas cycloheximide treatment inhibited stimulation only of exon I and II mRNAs. Trk B mRNA was rapidly and transiently reduced after glutamate application. Our results demonstrate that glutamate 1) regulates BDNF mRNA expression at an early developmental stage in hypothalamic neurons and 2) exerts a differential regulation of BDNF transcripts. J. Neurosci. Res. 66:377–389, 2001. © 2001 Wiley‐Liss, Inc.