Effects of brain-derived neurotrophic factor on dopaminergic function and motor behavior during aging.
Brain-derived neurotrophic factor (BDNF) is critical in synaptic plasticity and in the survival and function of midbrain dopamine neurons. In this study, we assessed the effects of a partial genetic deletion of BDNF on motor function and dopamine (DA) neurotransmitter measures by comparing Bdnf(+/-) with wildtype mice (WT) at different ages. Bdnf(+/-) and WT mice had similar body weights until 12 months of age; however, at 21 months, Bdnf(+/-) mice were significantly heavier than WT mice. Horizontal and vertical motor activity was reduced for Bdnf(+/-) compared to WT mice, but was not influenced by age. Performance on an accelerating rotarod declined with age for both genotypes and was exacerbated for Bdnf(+/-) mice. Body weight did not correlate with any of the three behavioral measures studied. Dopamine neurotransmitter markers indicated no genotypic difference in striatal tyrosine hydroxylase, DA transporter (DAT) or vesicular monoamine transporter 2 (VMAT2) immunoreactivity at any age. However, DA transport via DAT (starting at 12 months) and VMAT2 (starting at 3 months) as well as KCl-stimulated DA release were reduced in Bdnf(+/-) mice and declined with age suggesting an increasingly important role for BDNF in the release and uptake of DA with the aging process. These findings suggest that a BDNF expression deficit becomes more critical to dopaminergic dynamics and related behavioral activities with increasing age.
Boger
H A
HA
Department of Neurosciences and the Center on Aging, Medical University of South Carolina, Charleston, SC 29425, USA.
Mannangatti
P
P
Samuvel
D J
DJ
Saylor
A J
AJ
Bender
T S
TS
McGinty
J F
JF
Fortress
A M
AM
Zaman
V
V
Huang
P
P
Middaugh
L D
LD
Randall
P K
PK
Jayanthi
L D
LD
Rohrer
B
B
Helke
K L
KL
Granholm
A-C
AC
Ramamoorthy
S
S
D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005110:Extracellular Space / Q000502:physiology; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017551:Microdialysis; D009043:Motor Activity / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D013378:Substantia Nigra / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism
D019208:Brain-Derived Neurotrophic Factor; D050483:Dopamine Plasma Membrane Transport Proteins; C493453:Slc18a2 protein, mouse; D050493:Vesicular Monoamine Transport Proteins; D011188:Potassium; D004298:Dopamine