Dopamine Depletion and Locomotor Activity in Parkinson's Disease
I suspect there are few readers of this blog who have Parkinson's Disease (PD) or who are really concerned a the moment about potentially developing PD. So why are we discussing a neurodegenerative disease on this blog? A large part of the Paragon Method of Recovery has to do with restoring a natural circadian rhythm via dietary, lifestyle, and environmental choices in the society that is set up to disrupt a healthy sleep/wake cycle. The connection to be made between PD and the circadian rhythm lies in dopamine depletion and the role that dopamine plays in a natural circadian rhythm.
First, let's take a look at what common symptoms someone who is deficient in dopamine may have (1):
- Lack of interest in life
- Decreased motivation
- Inability to feel pleasure
- Altered sleep patterns
- Restless leg syndrome
- Mood swings
- Excessive feelings of hopelessness or guilt
- Poor memory
- Inability to focus/impaired concentration
- Impulsive or self-destructive behaviors
- Addictions to caffeine or other stimulants
- Weight gain
Sound familiar to anyone? Low dopamine levels are becoming increasingly common.
PD is hallmarked by extreme dopamine deficiency and provides a look at how dopamine, or a lack thereof, plays a role in a natural circadian rhythm.
The study that caught my attention today involved studying locomotor activity in primates in a controlled group and in a group given a drug known to induce permanent PD symptoms by destroying dopaminergic neurons in a specific region of the brain that plays a key role in movement and reward. Both the control and treated primates were exposed to a light/dark cycles of 12 hours each and intermittently 24 hour light for roughly 2 weeks before going back to the regular 12/12 light/dark cycle. By studying the same subjects in both light/dark cycles and pure light cycles, it allowed the researchers to account for known variabilities in expression and symptoms between PD patients
The results of the study showed that primates without a dopamine system to back their circadian rhythm lost most or all of their circadian rhythm driven locomotor control during exposures of 24 hour light cycles. While there was still evidence of this rhythm in light/dark cycles, amplitude of locomotor activity was severely blunted.
What does this tell us about the role of dopamine in circadian rhythm for optimal performance?
Dopamine begins to rise near the end of sleep as melatonin levels drop in healthy individuals. This rise peaks mid afternoon and begins to drop so the body can prepare for sleep. This rise and fall has to do with the synthesis of dopamine in the morning and the breakdown of dopamine in the afternoon by the midday sun's heavier blue light (or the LED screens in your tech devices) activating MAO-B in the eye.
Some interesting data for us comes from the control population in this study. Those primates had high amplitudes of locomotor activity during the day (compared to baseline at night), peaking in the afternoon, and falling again when the lights went out. Even in 24 hour light exposure, the locomotor activity retained its rhythmic nature even though the amplitude of activity was decreased. This rhythm matches studies in sports science showing that optimal performance occurs in the mid afternoon for most people and that bright lights can increase performance capabilities at times.
In terms of optimal recovery, having healthy dopamine levels plays a major role in:
- keeping dietary cravings at bay
- controlled decision making processes under stress
- addiction control
- memory and learning ability
- being in a good mood
- being capable of enjoying an unexpected reward.
These traits make it easier to keep healthy recovery habits like keeping a normal sleep/wake schedule, getting outside for a 10 minute walk 3 times per day, eating a healthy breakfast first thing in the morning, and unplugging from work and technology at least 1-2 hours before your scheduled bed time. All of these practices help entrain the circadian rhythm and aid in optimal recovery.
In terms of reducing the risk of developing PD, it is believed that the underlying mechanism of PD in humans is related to oxidative damage from free radicals and mitochondrial impairment. Veterans are more likely to develop PD than non veterans. TBI and chemical exposure, like Agent Orange, are well known to increase the risk further. Our method of recovery at Paragon is based on the optimization of mitochondrial function. We believe keeping the mitochondria in a state of higher energy helps improve recovery and prevent disease. An analogy to relate to would be in the functioning of electronics. As a battery gets closer to depletion, the device begins to malfunctions as there is no longer enough energy to function optimally, only enough to keep it powered on. Similarly, the RDA of Vitamin C is set a level just above the mean amount to prevent scurvy in humans, as opposed to having enough to be utilized for the vast amount of functions that vitamin does in the body. Contact us if you'd like to learn more about optimizing recovery at: Paragon Consulting.