title: An age-related decline in striatal taurine is correlated with a loss of dopaminergic markers.
abstract: Taurine is present in high concentration in the mammalian brain and is known to decline with aging. The present studies examined the relationship between the loss of striatal neurotransmitters and spatial learning ability in aged male Long-Evans rats. The effects of intrahippocampal infusions of neurotrophic factors-nerve growth factor (NGF) and brain-derived neurotrophic factor-were also examined for their ability to ameliorate the age-related decline in brain amino acid content. Taurine content was found to be significantly reduced in the striatum of aged rats (26 months old) that were impaired in spatial learning performance when compared to young unimpaired rats (5 months old). Aged rats that were behaviorally unimpaired had more modest reductions in taurine. Striatal dopamine content was also significantly reduced in aged learning-impaired rats. There was a significant (p < 0.001) correlation (r=0.61) between the striatal content of taurine and dopamine, but no such correlation was found for other striatal transmitters (glutamate, serotonin, norepinephrine). Treatment with neurotrophins had little effect on the age-related decline in striatal amino acids, although NGF treatment did improve spatial learning. These studies suggest (1) a link between age-related declines in striatal dopamine and taurine and (2) that NGF-induced improvement in spatial learning is not related to mechanisms involving changes in taurine or glutamate content.
authors.affiliation: Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610, USA. dawson@cop.health.ufl.edu
authors.forename: R
authors.initials: R
authors.lastname: Dawson
authors.forename: M A
authors.initials: MA
authors.lastname: Pelleymounter
authors.forename: M J
authors.initials: MJ
authors.lastname: Cullen
authors.forename: M
authors.initials: M
authors.lastname: Gollub
authors.forename: S
authors.initials: S
authors.lastname: Liu
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis; D000375:Aging / Q000502:physiology*; D000818:Animals; D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor / Q000502:physiology; D003342:Corpus Striatum / Q000737:chemistry / Q000378:metabolism*; D004298:Dopamine / Q000502:physiology*; D018698:Glutamic Acid / Q000032:analysis; D005973:Glutamine / Q000032:analysis; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009414:Nerve Growth Factors / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology; D013654:Taurine / Q000032:analysis / Q000378:metabolism*; D013702:Temporal Lobe / Q000737:chemistry / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D005973:Glutamine; D015102:3,4-Dihydroxyphenylacetic Acid; D013654:Taurine; D018698:Glutamic Acid; D004298:Dopamine