Did you know that BDNF is also needed in the proper development of the vestibular system?
Title: Degeneration of vestibular neurons in late embryogenesis of
both heterozygous and homozygous BDNF null mutant mice.
Author: Bianchi-L-M. Conover-J-C. Fritzsch-B. DeChiara-T.
Lindsay-R-M. Yancopoulos-G-D.
Address: Regeneron Pharmaceuticals Inc., Tarrytown, NY 10591, USA.
Source: DEVELOPMENT, (1996 Jun) vol. 122(6): 1965-73
Title Abbr: Development
Holdings: Norris Medical Library: 99-.1987-
Science & Engineering Library: v.99-, 1987-
Language: Eng Unique Identifier: 96232310
Abstract: The generation of mice lacking specific neurotrophins
permits evaluation of the trophic requirements of particular
neuronal populations throughout development. In the present
study, we examined the developing vestibulocochlear system
to determine the time course of neurotrophin dependence and
to determine whether competition occurred among developing
cochlear or vestibular neurons for available amounts of
either brain-derived neurotrophic factor (BDNF) or
neurotrophin-4/5 (NT-4/5). Both cochlear and vestibular
neurons were present in mice lacking NT-4/5. In contrast,
vestibular neurons decreased in number beginning at
mid-stages of inner ear development, in mice lacking BDNF.
Early in development (E12.5-13), the size of the vestibular
ganglion was normal in bdnf -/- mice. Decreased innervation
to vestibular sensory epithelia was detected at E13.5-15,
when progressive loss of all afferent innervation to the
semicircular canals and reduced innervation to the utricle
and saccule were observed. At E16.5-17, there was a
reduction in the number of vestibular neurons in bdnf -/-
mice. A further decrease in vestibular neurons was observed
at P1 and P15. Compared to bdnf -/- mice, mice heterozygous
for the BDNF null mutation (bdnf +/-) showed an intermediate
decrease in the number of vestibular neurons from E16.5-P15.
These data indicate a late developmental requirement of
vestibular neurons for BDNF and suggest competition among
these neurons for limited supplies of this factor.
Major MeSH
Headings: COCHLEA: innervation (ir). NERVE-TISSUE-PROTEINS:
physiology (ph). VESTIBULE: innervation (ir).
Minor MeSH
Headings: ANIMAL. COCHLEA: embryology (em). GANGLIA-SENSORY:
cytology (cy). GANGLIA-SENSORY: embryology (em).
HETEROZYGOTE. HOMOZYGOTE. MICE. MUTATION.
NERVE-DEGENERATION. NERVE-GROWTH-FACTORS: deficiency (df).
NERVE-GROWTH-FACTORS: metabolism (me).
NERVE-TISSUE-PROTEINS: deficiency (df).
NERVE-TISSUE-PROTEINS: genetics (ge). NEURONS.
SUPPORT-US-GOVT-PHS. VESTIBULE: embryology (em).
Publ Type: JOURNAL-ARTICLE. |
