Exercise Primes A Molecular Memory For Brain-Derived Neurotrophic Factor Protein Induction In The...
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Transcript of Exercise Primes A Molecular Memory For Brain-Derived Neurotrophic Factor Protein Induction In The...
Exercise Primes A Molecular Memory For Brain-Derived Neurotrophic Factor Protein
Induction In The Rat Hippocampus
N.C. Berchtold, et. Al.
BDNF
• Enhances synaptic transmission and neuronal excitability with upregulation of gene expression
• Modulates synaptic change such as LTP in the hippocampus– Deficiencies have shown to exhibit learning
deficits
• Essential survival factor and neuroprotectant
Impaired BDNF
• Factors in Alzheimer’s
• Mood and Eating disorders – Such as Depression
BDNF Benefits of Exercise
• Increased available BDNF for neuronal survival and resistance to brain insults
• Enhanced neurogenesis and LTP
• Increased resistance to Depression
• Lower risks of Alzheimer’s and dementia
• Allows for a lower threshold for theta-pattern stimulation for LTP
3 Questions of the Study
1. How do hippocampal BDNF protein levels respond to intermittent exercise?
2. Do BDNF protein levels remain elevated or decline rapidly to baseline?
3. How does a second exercise exposure regulate BDNF after levels have decayed to baseline?
Experiments
• Adult male Sprague-Dawley rats– 7 to 8 weeks old– 150 to 200 grams
• Food and water ad libitum
• 12 hr light/dark cycle
Levels of BDNF
• Either continuous daily access to running wheel and terminally sampled at 2, 4, 7, 14, 28, or 90 days.
Levels of BDNF
• Or intermittent access on alternating days of 7, 14, 21, or 28 days.
Stability of elevated BDNF
• 4 weeks of running, wheel locked and sampled at 0, 1, 3, 7, and 14 days.
Reintroduction of BDNF
• Determining if BDNF levels are related to absolute number of running days
• 14 days of priming run– continuous– intermittent
• 1 or 2 week of rest• A second test exercise of 2 days of running
Reintroduction of BDNF
• 2 weeks of daily running with either 1 week of rest
• Or 2 weeks of rest
Reintroduction of BDNF
• 4 weeks of intermittent running– 1 week of rest
– 2 weeks of rest
Results
BDNF daily vs. intermittent
• Continued to rise even for 90 days
222%
174%150%
BDNF daily vs. intermittent
• Similar increase, but slower rate
159%145%
124%
• BDNF has a time component that interacts with the exercise stimulus
• Intermittent training is ultimately as effective as daily training to elevate BDNF
BDNF elevated
• BDNF sampled at 0, 1, 3, 7, and 14 after 28 days of exercise
• BDNF sampled at 0, 3, and 7 days after 28 day period of alternating days of exercise
BDNF elevated
• Gradually declines, but slight rise at 7 days
151%128%
133%
BDNF elevated
• Levels no longer significant after 3 days
160%
BDNF “Memory”
• Daily runners– Sedentary
– 2 days of running
– 14 days of running
– 14 days of running with 7 days rest
– 14 days of running with 7 days rest + 2 days running
– 14 days running with 14 days rest
– 14 days running with 14 days rest + 2 days running
BDNF “Memory”
• Test run stimulates higher levels of BDNF
BDNF “Memory”
• Test run stimulates higher level, but takes longer to reach
Discussion
1. Intermittent exercise as effective as daily exercise to increase BDNF
• Progressively increase with longer running duration
• Induction of BDNF has time component that interacts with exercise stimulus
Paul A. Adlard Article
Significant increase in running at 4 weeks
Paul A. Adlard Article
• Shows that BDNF levels closely linked to level of activity as increases over 28 days
Discussion
2. BDNF levels remain elevated for several days
• Absolute amount of running days is important in regulating rate of decline
Discussion
3. BDNF is rapidly reinduced by brief exercise exposure, creating “molecular memory”
• May increase the conversion of precursor to BDNF or,
• May increase pool of available BDNF precursor
Jay’s Question’s
• Is the length or duration of each daily session have an effect on levels?
• Does the intensity of exercise during the session have an effect?