Do you know what dopamine is? Should you know what dopamine does and why it’s important? Dopamine is a common neurotransmitter. It is even more important for those with ADD, ADHD and impulse control issues.
Dopamine is just one of the brain’s slow down switches. It helps modulate the speed of neurotransmission. Dopamine acts in concert with the endocannabinoid system through the mechanism of retrograde inhibition. Dopamine depolarizes the presynaptic neuron.
This is a result of cannabinoids that come from the post synaptic neuron just after it has been stimulated. This depolarization, called retrograde inhibition, makes it more difficult for the subsequent neural impulse to stimulate that neuron until it’s at least partially repolarized. This mechanism of retrograde inhibition then causes fewer and slower moving neural stimuli to be transmitted to the midbrain and the forebrain.
The endocannabinoid system is important because it makes dopamine available to the brain; in particular the dopamine influences the presynaptic neuron by depolarizing it. Cannabinoids cause the release of dopamine from dopamine transporter. Release of this bound dopamine from dopamine binding sits on another normal neuro-chemical, dopamine transporter, which provides more free dopamine. This increases the effects of retrograde inhibition.
So what does that all mean? The more cannabinoids you have, the more dopamine release you have and the more retrograde inhibition you have. This results in fewer and slower moving neural impulses being sent up the nervous system.
This increase in available dopamine, particularly in those with low dopamine levels, acts to decrease neural input to the midbrain and thereby decrease overstimulation of the midbrain. Such overstimulation, according to research by Piomelli, is associated with ADHD, panic attacks and Tourette’s Syndrome. Work by Wilson and Nicholl found that the cannabinoids themselves act as a feedback mechanism that regulates the sensitivity of nerve cells that prevents excessive activity.
Low available dopamine could be genetic (1) some people naturally produce less dopamine than others or (2) having too many dopamine transporters. Some studies have shown that those with ADD/ADHD have 70 percent more dopamine transporters than the average. The dopamine transporter ties up much of the free dopamine making it less available for retrograde inhibition.
PTSD/Dopamine Transporter/Impulse Control
Trauma induces PTSD. This trauma can be war, rape, natural disaster or growing up in a dysfunctional family, which can cause excess dopamine transporters to be manufactured by the brain. It is postulated that this exposure to traumatic events can cause an increase in the production or availability of dopamine transporters it is by a mechanism yet to be explained.
Decreasing the over-stimulation of neural structures in the midbrain and forebrain has a tremendous beneficial impact on many conditions which are probably caused by over-stimulation of the midbrain. When it comes to impulse control slowing the speed, you give the forebrain an opportunity to influence the more primitive midbrain. The midbrain, sometimes referred to as the reptilian brain, sees things only as black/white or life/death matters. Optimally we would like to think first and act later, but if the midbrain holds too much sway in our thinking we are more likely to act first and think later.
The availability of more dopamine made possible by cannabinoids occupying dopamine binding sites on the dopamine transporter causes an increase in available dopamine and a decrease in the speed and frequency of neural stimulation to the midbrain and thus helps manage the symptoms of PTSD, ADD/ADHD. This slowing down of speed provides more time for the frontal cortex, the newest and more civilized part of the brain, to influence our actions by giving the brain time to think first and then act.