PMID- 28600222 OWN - NLM STAT- MEDLINE DCOM- 20180424 LR - 20181113 IS - 1095-9327 (Electronic) IS - 1044-7431 (Print) IS - 1044-7431 (Linking) VI - 82 DP - 2017 Jul TI - Taste bud-derived BDNF maintains innervation of a subset of TrkB-expressing gustatory nerve fibers. PG - 195-203 LID - S1044-7431(17)30014-3 [pii] LID - 10.1016/j.mcn.2017.06.001 [doi] AB - Taste receptor cells transduce different types of taste stimuli and transmit this information to gustatory neurons that carry it to the brain. Taste receptor cells turn over continuously in adulthood, requiring constant new innervation from nerve fibers. Therefore, the maintenance of innervation to taste buds is an active process mediated by many factors, including brain-derived neurotrophic factor (BDNF). Specifically, 40% of taste bud innervation is lost when Bdnf is removed during adulthood. Here we speculated that not all gustatory nerve fibers express the BDNF receptor, TrkB, resulting in subsets of neurons that vary in their response to BDNF. However, it is also possible that the partial loss of innervation occurred because the Bdnf gene was not effectively removed. To test these possibilities, we first determined that not all gustatory nerve fibers express the TrkB receptor in adult mice. We then verified the efficiency of Bdnf removal specifically in taste buds of K14-CreER:Bdnf mice and found that Bdnf expression was reduced to 1%, indicating efficient Bdnf gene recombination. BDNF removal resulted in a 55% loss of TrkB-expressing nerve fibers, which was greater than the loss of P2X3-positive fibers (39%), likely because taste buds were innervated by P2X3+/TrkB- fibers that were unaffected by BDNF removal. We conclude that gustatory innervation consists of both TrkB-positive and TrkB-negative taste fibers and that BDNF is specifically important for maintaining TrkB-positive innervation to taste buds. In addition, although taste bud size was not affected by inducible Bdnf removal, the expression of the gamma subunit of the ENaC channel was reduced. So, BDNF may regulate expression of some molecular components of taste transduction pathways. CI - Copyright (c) 2017. Published by Elsevier Inc. FAU - Tang, Tao AU - Tang T AD - Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA. FAU - Rios-Pilier, Jennifer AU - Rios-Pilier J AD - Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA. FAU - Krimm, Robin AU - Krimm R AD - Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA. Electronic address: rfkrim01@louisville.edu. LA - eng GR - P30 GM103507/GM/NIGMS NIH HHS/United States GR - R01 DC007176/DC/NIDCD NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural DEP - 20170620 PL - United States TA - Mol Cell Neurosci JT - Molecular and cellular neurosciences JID - 9100095 RN - 0 (Brain-Derived Neurotrophic Factor) RN - 0 (Receptors, Purinergic P2X3) RN - EC 2.7.10.1 (Receptor, trkB) SB - IM MH - Animals MH - Brain-Derived Neurotrophic Factor/*metabolism MH - Mice MH - Nerve Fibers/*metabolism MH - Neurons/*metabolism MH - Receptor, trkB/metabolism MH - Receptors, Purinergic P2X3/metabolism MH - Taste Buds/*metabolism PMC - PMC5920676 MID - NIHMS959999 OTO - NOTNLM OT - BDNF OT - Neurotrophins OT - Sensory OT - Taste OT - Taste bud innervation OT - TrkB EDAT- 2017/06/11 06:00 MHDA- 2018/04/25 06:00 PMCR- 2018/04/26 CRDT- 2017/06/11 06:00 PHST- 2017/01/16 00:00 [received] PHST- 2017/05/08 00:00 [revised] PHST- 2017/06/05 00:00 [accepted] PHST- 2017/06/11 06:00 [pubmed] PHST- 2018/04/25 06:00 [medline] PHST- 2017/06/11 06:00 [entrez] PHST- 2018/04/26 00:00 [pmc-release] AID - S1044-7431(17)30014-3 [pii] AID - 10.1016/j.mcn.2017.06.001 [doi] PST - ppublish SO - Mol Cell Neurosci. 2017 Jul;82:195-203. doi: 10.1016/j.mcn.2017.06.001. Epub 2017 Jun 20.