title: Lingual deficits in neurotrophin double knockout mice.
abstract: Brain-derived neurotrophic factor (BDNF) and Neurotrophin 3 (NT-3) are members of the neurotrophin family and are expressed in the developing and adult tongue papillae. BDNF null-mutated mice exhibit specific impairments related to innervation and development of the gustatory system while NT-3 null mice have deficits in their lingual somatosensory innervation. To further evaluate the functional specificity of these neurotrophins in the peripheral gustatory system, we generated double BDNF/NT-3 knockout mice and compared the phenotype to BDNF(-/-) and wild-type mice. Taste papillae morphology was severely distorted in BDNF(-/-) xNT-3(-/-) mice compared to single BDNF(-/-) and wild-type mice. The deficits were found throughout the tongue and all gustatory papillae. There was a significant loss of fungiform papillae and the papillae were smaller in size compared to BDNF(-/-) and wild-type mice. Circumvallate papillae in the double knockouts were smaller and did not contain any intraepithelial nerve fibers. BDNF(-/-) xNT-3(-/-) mice exhibited additive losses in both somatosensory and gustatory innervation indicating that BDNF and NT-3 exert specific roles in the innervation of the tongue. However, the additional loss of fungiform papillae and taste buds in BDNF(-/-) xNT-3(-/-) mice compared to single BDNF knockout mice indicate a synergistic functional role for both BDNF-dependent gustatory and NT-3-dependent somatosensory innervations in taste bud and taste papillae innervation and development.
authors.affiliation: Laboratory of Oral Neurobiology, Department of Biological and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Irina V
authors.initials: IV
authors.lastname: Nosrat
authors.forename: Karin
authors.initials: K
authors.lastname: Agerman
authors.forename: Andrea
authors.initials: A
authors.lastname: Marinescu
authors.forename: Patrik
authors.initials: P
authors.lastname: Ernfors
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Nosrat
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D002814:Chorda Tympani Nerve / Q000002:abnormalities* / Q000648:ultrastructure; D005260:Female; D007150:Immunohistochemistry; D008036:Lingual Nerve / Q000002:abnormalities* / Q000648:ultrastructure; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism; D009475:Neurons, Afferent / Q000502:physiology* / Q000648:ultrastructure; D020933:Neurotrophin 3 / Q000235:genetics / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000502:physiology / Q000648:ultrastructure; D013649:Taste / Q000235:genetics; D013650:Taste Buds / Q000002:abnormalities* / Q000648:ultrastructure; D014059:Tongue / Q000002:abnormalities* / Q000294:innervation / Q000648:ultrastructure; D014110:Touch / Q000235:genetics
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D020933:Neurotrophin 3