title: The noradrenergic system of aged GDNF heterozygous mice.
abstract: Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for noradrenergic (NE) neurons of the pontine nucleus locus coeruleus (LC). Decreased function of the LC-NE neurons has been found during normal aging and in neurodegenerative disorders. We have previously shown that GDNF participates in the differentiation of LC-NE neurons during development. However, the continued role of GDNF for LC-NE neurons during maturation and aging has not been addressed. We examined alterations in aged mice that were heterozygous for the GDNF gene (Gdnf+/-). Wild-type (Gdnf+/+) and Gdnf+/- mice (18 months old) were tested for locomotor activity and brain tissues were collected for measuring norepinephrine levels and uptake, as well as for morphological analysis. Spontaneous locomotion was reduced in Gdnf+/- mice in comparison with Gdnf+/+ mice. The reduced locomotor activity of Gdnf+/- mice was accompanied by reductions in NE transporter activity in the cerebellum and brain stem as well as decreased norepinephrine tissue levels in the LC. Tyrosine hydroxylase (TH) immunostaining demonstrated morphological alterations of LC-NE cell bodies and abnormal TH-positive fibers in the hippocampus, cerebellum, and frontal cortex of Gdnf+/- mice. These findings suggest that the LC-NE system of Gdnf+/- mice is impaired and suggest that GDNF plays an important role in continued maintenance of this neuronal system throughout life.
authors.affiliation: Department of Physiology and Neuroscience, Center on Aging, Medical University of South Carolina, Charleston, SC 29425, USA.
authors.forename: V
authors.initials: V
authors.lastname: Zaman
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: L
authors.initials: L
authors.lastname: Middaugh
authors.forename: S
authors.initials: S
authors.lastname: Ramamoorthy
authors.forename: B
authors.initials: B
authors.lastname: Rohrer
authors.forename: M E
authors.initials: ME
authors.lastname: Nelson
authors.forename: A C
authors.initials: AC
authors.lastname: Tomac
authors.forename: B J
authors.initials: BJ
authors.lastname: Hoffer
authors.forename: G A
authors.initials: GA
authors.lastname: Gerhardt
authors.forename: A Ch
authors.initials: ACh
authors.lastname: Granholm
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001923:Brain Chemistry; D001933:Brain Stem / Q000378:metabolism; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D005625:Frontal Lobe / Q000166:cytology / Q000378:metabolism; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D008125:Locus Coeruleus / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity / Q000502:physiology; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000502:physiology; D009638:Norepinephrine / Q000737:chemistry / Q000378:metabolism*; D050484:Norepinephrine Plasma Membrane Transport Proteins; D027981:Symporters / Q000378:metabolism; D013574:Synaptosomes / Q000737:chemistry / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: C495040:Gdnf protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D050484:Norepinephrine Plasma Membrane Transport Proteins; C493228:Slc6a2 protein, mouse; D027981:Symporters; D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine