Which Neurotransmitters should be tested?
Below is an overview of six important neurotransmitters and their respective roles in various symptomatic conditions. Refer to the neurotransmitter test menu for panel options.
SEROTONIN is a significant neurotransmitter, its presence or absence being felt in a large number of areas of the body. Serotonin plays an important part in the regulation of learning, mood, sleep and vasoconstriction (constriction of blood vessels) as well as impacting anxiety, migraines, and appetite. Serotonin is an inhibitory neurotransmitter and adequate amounts of serotonin are necessary to balance any excessive excitatory (stimulating) neurotransmitters firing in the hypothalamus. Other functions impacted by serotonin include metabolic processes, digestion, and immune function.
HHigh stress, insufficient nutrients, fluctuating hormones, and the use of stimulant medications or caffeine all contribute to the depletion of serotonin over time. About 80% of the body's total serotonin is in the gut, in the enterochromaffin cells - where it regulates intestinal movements. The rest is synthesized in the serotonergic neurons in the central nervous system. When serotonin levels are too high or too low, then a multitude of symptoms may appear including depression, anxiety, PMS, heightened pain response, sleep disruption, carbohydrate cravings, obsessive thoughts and behaviors. Serotonin levels can have a significant impact on feelings of happiness and contentment and adequate levels are important to protect against anxiety and depression.
GABA is the main inhibitory neurotransmitter produced to counterbalance the excitatory effects of neurotransmitters such as norepinephrine and epinephrine. GABA is a significant. GABA is a significant mood modulator, essential for regulating norepinephrine, epinephrine, dopamine, and serotonin. High levels of GABA may indicate excitatory overload, due to the increased demand for GABA to balance the surplus excitatory neurotransmitter activity. These high levels may result in a ‘calming’ action that contributes to sluggish energy, feelings of sedation, and foggy thinking. Low GABA levels are associated with adrenal distress and Hypothalamus-Pituitary-Adrenal Axis (HPA Axis) feedback dysfunction. Without the inhibiting function of GABA, impulsive behaviors are not controlled, contributing to a range of anxious and/or reactive symptoms that extend from poor impulse control to seizure disorders.
DOPAMINE DOPAMINE is the neurotransmitter most powerfully associated with reward-driven learning, development of memories and for motor control. Dopamine can bind to five known types of receptors and can function both as an excitatory AND an inhibitory neurotransmitter depending on which receptor it binds to. When dopamine is either elevated or low, memory issues frequently occur: forgetting where items are, forgetting what a paragraph said immediately after reading, or simply daydreaming and not being able to stay on task. Stimulants such as medications for ADD/ADHD and caffeine will cause dopamine to be pushed into the synapse so that focus is improved. Unfortunately, stimulating dopamine continually can inhibit natural transmission, reducing demand and contributing to depletion of dopamine over time.
Common symptoms with low dopamine levels include loss of motor control, addictive behavior, cravings, compulsions, and loss of satisfaction. These feelings lead to drug use, drinking alcohol, smoking cigarettes, gambling, and overeating. These actions are a result of an unconscious attempt to self medicate, looking for the satisfaction that is not occurring naturally in the body.
When dopamine levels are elevated, symptoms may manifest in the form of anxiety or hyperactivity. High dopamine has been observed in patients with poor GI function, autism, mood swings, psychosis and children with attention disorders. L-DOPA is a precursor to dopamine, and may also cause elevations in dopamine. Some therapies utilize L-DOPA for parkinsonian symptoms.
NOREPINEPHRINE (Nor-Adrenaline) is an excitatory neurotransmitter responsible for stimulatory processes for attention and focus. It is produced by the adrenal medulla or synthesized from dopamine. Norepinephrine plays a critical role in survival. First, it relays messages in the sympathetic nervous system as part of the autonomic nervous system’s fight-or-flight response. Second, norepinephrine prepares the brain to encounter and respond to stimuli from the environment thereby facilitating vigilance. In both roles, norepinephrine mediates arousal.
If norepinephrine levels are elevated over a long period, then resulting symptoms include stress, anxiety, high blood pressure, hyperactivity. Symptoms of low norepinephrine include fatigue, lack of energy, reduced capacity to focus, and reduced motivation.
EPINEPHRINE (Adrenaline) is synthesized from norepinephrine, and is an excitatory neurotransmitter that helps regulate metabolism, heart rate, and blood pressure. Epinephrine is involved in managing the body’s metabolic “fight or flight” response, rapidly preparing the body for action, boosting the supply of oxygen and glucose to the brain and muscles, increasing heart rate, dilating the pupils, while suppressing other non-emergency bodily processes (digestion in particular). It also increases catabolism of glycogen to glucose in the liver, thereby elevating the blood sugar level so the body is ready to respond swiftly to the real or perceived threat.
Elevated levels of epinephrine are associated with hyperactivity, ADHD, anxiety, sleep issues, and low adrenal function. Low levels are associated with poor concentration, fatigue, poor recovery from illness, dizziness, decreased energy and depression. Low levels are frequently linked with insufficient cortisol production, chronic stress and burnout. Long-term over-stimulation of the adrenal glands can cause epinephrine stores to be depleted, resulting in chronic low energy, altered metabolism and weight gain.
GLUTAMATE is a key compound in cellular metabolism. It is the most abundant excitatory neurotransmitter and, because if it’s role in synaptic plasticity, is involved most aspects of normal brain function including cognition, memory and learning. Glutamate also serves as the precursor for the synthesis of the inhibitory GABA in GABA-ergic neurons.
Consistently high levels of glutamate can be an indicator of excitotoxicity. Elevated glutamate levels are more commonly associated with panic attacks, anxiety, excess adrenal function, impulsivity, OCD and depression. Low glutamate levels have been associated with agitation, memory loss, sleeplessness, low energy level, insufficient adrenal function, and depression.