Neurobiology" Understanding Dopamine Serotonin & GABA

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