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Neurobiology: Dopamine, GABA, Serotonin,
AcetylcholineDr. Dawn-Elise Snipes PhD, LPC-MHSP, LMHC, NCC, CCDC
Executive Director, AllCEUs.com
Define Neurobiology For the following neurotransmitters, Dopamine,
GABA, Serotonin, Acetylcholine, identify◦ Their mechanism of action/purpose◦ Where they are found◦ Symptoms of excess & insufficiency◦ Nutritional building blocks◦ Medications
Objectives
Neurobiology is the study of the brain and nervous system which generate sensation, perception, movement, learning, emotion, and many of the functions that make us human
What is Neurobiology
Mechanism of action/purpose◦ movement◦ memory◦ pleasurable reward◦ behavior and cognition◦ attention◦ inhibition of prolactin production◦ sleep◦ mood◦ learning
Dopamine
Mechanism of action/purpose◦ Altered dopamine neurotransmission is implicated
in Cognitive control (racing thoughts) Attentional control Impulse control Working memory
Dopamine
Where is it found◦ Precursor, L-DOPA is synthesized in brain and kidneys◦ Dopamine functions in several parts of the
peripheral nervous system In blood vessels, it inhibits norepinephrine release and acts
as a vasodilator (relaxation) In the kidneys, it increases sodium and urine excretion In the pancreas, it reduces insulin production In the digestive system, it reduces gastrointestinal motility
and protects intestinal mucosa In the immune system, it reduces lymphocyte activity.
Dopamine
Symptoms of excess & insufficiency◦ Excess of dopamine
Unnecessary movements, repetitive tics Psychosis Hypersexuality Nausea Most antipsychotic drugs are dopamine antagonists Dopamine antagonist drugs are also some of the
most effective anti-nausea agents
Dopamine
Symptoms of excess & insufficiency◦ Insufficient dopamine
Negative symptoms of schizophrenia Pain Parkinson’s Disease Restless legs syndrome Attention deficit hyperactivity disorder (ADHD) Neurological symptoms that increase in frequency with age, such
as decreased arm swing and increased rigidity. Changes in dopamine levels may also cause age-related changes
in cognitive flexibility.
Dopamine
Symptoms of excess & insufficiency◦ Insufficient dopamine
Lack of motivation Fatigue Apathy, Inability to feel pleasure Procrastination Low libido Sleep problems Mood swings Hopelessness Memory loss Inability to concentrate
Dopamine
Nutritional building blocks◦ Eating a diet high in magnesium and tyrosine rich foods will ensure
you’ve got the basic building blocks needed for dopamine production.◦ Here’s a list of foods known to increase dopamine:
Dopamine
ChickenAlmondsApplesAvocadoBananasBeets Chocolate
Green leafy vegetablesGreen teaLima beansOatmealSesame & pumpkin seeds
TurmericWatermelonWheat germ
Medications◦ Dopamine in blood is unable to cross the blood-
brain barrier to reach the brain. ◦ Levodopa-Carbidopa combination is actually
converted to dopamine in the brain
Dopamine
Medications◦ Most common dopamine antagonists (positive
symptoms) Risperdone, Haldol, Zyprexa Metoclopramide (Reglan) is an antiemetic and
antipsychotic◦ Most common dopamine AGONISTs (Parkinson’s,
Restless Legs) (negative symptoms) Mirapex & Requip
Dopamine
Patients with schizophrenia do not typically show measurably increased levels of brain dopamine activity
Other dissociative drugs, notably ketamine and phencyclidine that act on glutamate NMDA receptors (and not on dopamine receptors) can produce psychotic symptoms.
Those drugs that do reduce dopamine activity are a very imperfect treatment for schizophrenia: they only reduce a subset of symptoms, while producing severe short-term and long-term side effects
Dopamine Hypothesis
Mechanism of action/purpose◦ Anti-anxiety, Anti-convulsant◦ GABA is made from glutamate◦ GABA functions as an inhibitory neurotransmitter
–◦ Glutamate acts as an excitatory neurotransmitter ◦ GABA does the opposite and tells the adjoining
cells not to “fire”
GABA
Where they are found◦ Close to 40% of the synapses in the human brain
work with GABA and therefore have GABA receptors.
GABA
◦ Symptoms of excess Excess sleepiness Shallow breathing *Increased blood pressure
◦ Symptoms of insufficiency Anxiety Depression Difficulty concentrating Insomnia Seizure disorders
GABA
Nutritional building blocks Fermented foods sauerkraut, yogurt Almonds & Walnuts Cherry Tomatoes Banana Brown rice Potato Oats Lentils Vitamin B6, if deficient, may impair the production of GABA as it is
a cofactor nutrient.
GABA
Nutritional building blocks◦ Inositol (Vitamin B-8)
Wheat germ Brown rice Green leafy vegetables Nuts Navy and Lima beans
GABA
Medications◦ Drugs that act as allosteric modulators of
GABA receptors (known as GABA analogues or GABAergic drugs) or increase the available amount of GABA typically have relaxing, anti-anxiety, and anti-convulsive effect
◦ Gabapentin (neurontin) is a GABA analogue used to treat epilepsy and neurotic pain.
◦ Benzodiazepines and Barbiturates including GHB, Valium, Xanax
GABA
Mechanism of action/purpose◦ Helps regulate
Mood Sleep patterns Appetite Pain
Serotonin
Where is it found◦ Brain◦ Gut/Intestines
Serotonin
Symptoms of excess◦ Shivering◦ Diarrhea◦ Muscle rigity◦ Fever◦ Seizures◦ Irregular heartbeat
Serotonin
Symptoms of excess◦ Depression◦ Apathy, Emotional flatness or dullness◦ Passivity◦ Insomnia and other sleep problems◦ Difficulty concentrating and learning◦ Poor memory; amnesia◦ Difficulty making decisions and acting on them◦ Sexual dysfunction
Serotonin
Insufficiency◦ Depression◦ Anxiety◦ Pain sensitivity
Serotonin
Nutritional building blocks◦ Foods rich in tryptophan, an amino acid that
converts to serotonin in the brain. Whole-wheat Potatoes Brown rice Lentils Oats Beans
Serotonin
Medications◦ SSRIs◦ SNRIs◦ 5-HTP◦ SAM-e
Serotonin
Their mechanism of action/purpose◦ In lower amounts, ACh can act like a stimulant by
releasing norepinephrine (NE) and dopamine (DA).◦ Memory◦ Motivation◦ Higher-order thought processes◦ Sexual desire and activity◦ Sleep
Acetylcholine
Symptoms of excess Depression (all symptoms) Nightmares Mental Fatigue Anxiety
Inverse relationship between serotonin and acetylcholine
Acetylcholine
◦ Insufficiency Alzheimers/dementia Parkinsons Impaired cognition, attention, and arousal
Cholinergic and GABAergic pathways are intimately connected in the hippocampus and basal forebrain complex.
Acetylcholine
◦ Nutritional building blocks Foods high in choline
Meats Dairy Poultry Chocolate Peanut butter Wheat germ Brussels sprouts and broccoli
Acetylcholine
Medications◦ Cholinergics
Used for glaucoma, bladder control and severe muscle weakness◦ Anticholinergics
May worsen GERD Used for extrapyrimadal symptoms is treating schizophrenia
Muscular spasms Akathisia: A feeling of internal motor restlessness, tension, nervousness,
or anxiety[ Drug-induced parkinsonism Tardive dyskinesia: involuntary muscle movements in the lower face and
distal extremities
Acetylcholine
Medications◦ Anticholinergics
Atropine Benzatropine (Cogentin) Chlorpheniramine (Chlor-Trimeton) Dimenhydrinate (Dramamine) Diphenhydramine (Benadryl, Sominex, Advil PM, Unisom) Hydroxyzine (Atarax, Vistaril) Bupropion (Zyban, Wellbutrin) Dextromethorphan - Cough suppressant
Acetylcholine
Anticholinergic drugs are used to treat a variety of conditions:◦ Gastrointestinal disorders (e.g., gastritis, diarrhea,
diverticulitis, ulcerative colitis, nausea, and vomiting)◦ Genitourinary disorders (e.g., cystitis, urethritis,
prostatitis)◦ Respiratory disorders (e.g., asthma, chronic bronchitis,
and chronic obstructive pulmonary disease [COPD])◦ Insomnia, although usually only on a short-term basis.
Acetylcholine
Higher ACh and NE, together with lower SE, produces ◦ Anxiety, emotional lability, irritability, anger, aggressiveness,
negative rumination, impatience, and impulsiveness When NE, DA, and SE are low and acetylcholine is
high◦ The result is simply depression.
Increasing serotonin ◦ lowers acetylcholine levels, and norepinephrine and dopamine.
Homeostasis
There are a variety of different neurotransmitters involved in addiction and mental health disorders
It is not always about increasing a neurotransmitter. Sometimes you need to decrease it.
Human brains try to maintain homeostasis and too much or too little can be bad
A balanced diet will provide the brain the necessary nutrients in synergystic combinations
Summary
Res Nurs Health. 2014 Jun;37(3):185-93. doi: 10.1002/nur.21595. Epub 2014 Apr 3. Neurobehavioral effects of aspartame consumption.Lindseth GN1, Coolahan SE, Petros TV, Lindseth PD.
http://www.smithsonianmag.com/science-nature/could-diet-soda-cause-clinical-depression-586801/?no-ist
Understanding our Bodies: Dopamine and Its Rewards http://nutritionwonderland.com/2009/07/understanding-our-bodies-dopamine-rewards/
http://nutritionwonderland.com/2009/06/understanding-bodies-serotonin-connection-between-food-and-mood/
References
Myo-inositol content of common foods: development of a high-myo-inositol diet. http://ajcn.nutrition.org/content/33/9/1954.abstract
Neuroscience. 2002;111(2):231-9. GABA mechanisms and sleep. Gottesmann C.
Biofactors. 2006;26(3):201-8. Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans. Abdou AM1, Higashiguchi S, Horie K, Kim M, Hatta H, Yokogoshi H.
References
Neuropsychopharmacology: The Fifth Generation of Progress Editors: Kenneth L. Davis et. Al. Publisher Lippincott, Williams, & Wilkins, Philadelphia, Pennsylvania, 2002 http://www.acnp.org/publications/neuro5thgeneration.aspx
References