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Neuro Transmitters
Neuro Transmitters are special type of chemicals that functions as a coveying material which transfer a signal from one neuron to another neuron. More specifically, these chemical (called neuro transmitter) is released from a part of one neuron (pre-synaptic neuron), swim through space called synaptic gap and reaches to the destination called a part of another neuron (post-synaptic neuron).
In this note I will introduce a list of neurotransmitters and the list will get longer as I learn more on this subject. Don't try to memorize everything in the list. It would not be much of use if you just memorize and it will be confusing as well since some neurotransmitters work differently depending on which part of the brain (or nerveous system) they are being used. Use this
page as a mini dictionary or cheatsheet whenever you want to check about any specific neurotransmitter while you are reading text or watching lectures.
List of Neurotransmitters
Acetylcholine
Image Source : PubChem
Functions in Peripheral Nervous System (PNS)
- excitatory role leading to the voluntary activation of muscles
- contraction of smooth muscles
- dilation of blood vessels
- slow heart rate
- increase body secretions
Functions in Brain and Central Nervous System (CNS)
- function as a neurotransmitter and a neuromodulator
- involved in motivation, arousal, attention, learning, memory
- promotes REM sleep
Medical Conditions related to Acetylcholine Dysfunction
- Alzheimer's Disease
- Parkinson's Disease
- Myasthenia Gravis
Medications that affect Acetylcholine
- Botox
- ACheE(Acetylecholinesterase inhibitors
- Anticholinergics
GABA (γ-Amino Butyric Acid)
Image Source : PubChem
Function :
- an inhibitory neurotransmitter in central nervous system (main inhibitor in our brain)==> Opposite funtionality against Glutamate
- When GABA binds to the receptor (GABA-A or GABA-B receptors), the responsiveness of the nerve cell decreases
- In this way, GABA van slow down certain brain function that is thought to do followings :
- Reduce stress
- Relieve anxiety
- Improve sleep
Medical Conditions related to decreased GABA level :
- Anxiety and mood disorders.
- Schizophrenia.
- Autism spectrum disorder : : Decreased GABA is observed in the brain (Update on Brain Research in Autism)
- Depression.
- Epilepsy, seizures.
Medical Conditions related to GABA Imbalance :
- Pyridoxine deficiency.
- Hepatic encephalopathy.
- Huntington disease.
- Dystonia and spasticity.
- Hypersomnia (excess daytime sleepiness or excessive time spent sleeping).
Glutamate
Image Source : PubChem
Function :
- an excitatory neurotransmitter in central nervous system (main excitatory neurotransmittor in our brain) ==> Opposite funtionality against GABA
- major excitatory neurotransmitter in the central nervous system.
- present in 90% of the excitatory synapses
- plays a key role in the plasticity of the nervous system
- plays a role in glia-neuron signalling, along with two other neurotransmitters: D-serine and glycine
Medical Conditions related to Glutamate dysfunction :
Medical Condition related to too much Glutamate :
- Parkinson's disease
- Alzheimer's disease
- Huntington's disease
Medical Conditions related to too little Glutamate
- Trouble concentrating
- Mental exhaustion
- Insomnia
- Low energy
Histamine
Image Source : PubChem
Function
- Based on Receptor types
- H1 receptors
- regulate neuronal excitation in most brain regions (brain step, hypothalamus,thalamus, amygdala, septup, hippocampus, olfactory bulb, cortex
- decrease the neuronal cells excitability and inhibits the cells firing in hippocampal pyramidal neurons
- H2 receptors
- mainly found in the basal ganglia, amygdala,hippocampus and cortex
- regulate the neuronal physiology and plasticity
- (in mice) a deficiency in H2R function cause cognitive deficits, impairment in hippocampla LTP, abnormalities in nociception
- H3 receptors
- act as a presynaptic heteroreceptor and release a variety of other transmitters (e.g, biogenic amines, acetylcholine, glutamate, GABA, peptidergic systems)
- (in mice) the loss of H3R function is associated with behavioral state abnormalities (e.g, hyperphagia, late-onset obesity, increased insulin and leptin levels)
- Based on locations
- Thalamus and cerebral cortex : Arousal and wakefullness
- Hypothalamus, glial cells and blood vessels: Homeostatic process (e.g, ood and water intake, hormones secretion, temperature regulation, among others)
Dopamine
Image Source : PubChem
Function
- Plays a role as a reward center
- involved in various functions as follows
- Pleasurable reward and motivation
- memory
- movement
- motivation
- mood
- attention
- sleep and arousal
- learning
- lactation
Medical condition associated with low level of dompamine
- ADHD (Attention Deficit Hyperactivity Disorder)
- Parkinson's disease
- Restless legs syndrome
- Schizonphrenia
Medical condition associated with high level of dompamine
Serotonin / 5-hydroxytryptamine (5-HT)
Image Source : PubChem
Functions :
- in brain
- involved in mood stabilization(known as 'feel-good' chemical),cognition,learning,memory,sleep
- effect on libido (high serotonine level may decrease sexual desire)
- in other body parts
- contributes to normal bowel function
- reduce appetite when you are full
- play a protective role in the gut
- help blood clotting
- influence bone density (high circulating serotonine level in the but might cause low bone density (e.g osteoporosis)
Signs of Low Serotonin :
- Disrupted sleep patterns
- Loss of appetite
- Mood Changes
- Trouble with memory and learning
NorAdrenaline / Nor Ephenephrine
Image Source : PubChem
Function
- Made from nerve cells in the brainstep area and the arean near spinal cord
- plays important roles in the fight-or-flight response
- Increase alertness,arousal and attention
- Contricts blood vessels, which helps maintain blood pressure under stress condition
- affect sleep-wake cycle, mood and memory
- reaches various organs as follows and cause rapid body reactions like fight-or-flight response
- Eyes
- Skin
- Heart
- Muscles
- Liver
- Airways
- adrena gland
Medical Conditions related to low level of norepinephrine
- Axiety
- Depression
- Attention deficit hyperacticity disorder (ADHD)
- Headaches
- Memory problems
- Sleeping problems
- Low blood pressure (hypotension)
- Low blood sugar (hypoglycemia)
- Changes in blood pressure, heart rate
- Dopamine beta-hydroxylase deficiency
Medical Conditions related to high level of norepinephrine
- High blood pressure (hypertension)
- Rapid or irregular heartbeat
- Excessive sweating
- Cold or pale skin
- Severe headaches
- Nervous feeling, jitters
- Pheochromocytoma (adrenal gland tumor)
Adrenaline /Ephenephrine
Image Source : PubChem
Function
- plays both as a neurotransmitter and hormone but plays relatively small role as neurotransmitter
- plays important roles in the fight-or-flight response
- Increase alertness,arousal and attention
- Contricts blood vessels, which helps maintain blood pressure under stress condition
- affect sleep-wake cycle, mood and memory
- reaches various organs as follows and cause rapid body reactions like fight-or-flight response
- Eyes
- Skin
- Heart
- Muscles
- Liver
- Airways
- adrena gland
Medical Conditions related to low level of norepinephrine
- Axiety
- Depression
- Attention deficit hyperacticity disorder (ADHD)
- Headaches
- Sleeping problems
- Low blood sugar (hypoglycemia)
- Changes in blood pressure, heart rate
Medical Conditions related to high level of norepinephrine
- High blood pressure (hypertension)
- Rapid or irregular heartbeat
- Excessive sweating
- Cold or pale skin
- Severe headaches
- Nervous feeling, jitters
- Pheochromocytoma (adrenal gland tumor)
NOTE : Overall functionality of Nor-epinephrine may sound very similar to the functionality of Epinephrine and sound confusing. Check out the section 'What are the similarities and differences between epinephrine and norepinephrine?' of this document for clarification on similarity and differences between nor-epinephrine and apinephrine.
L-Aspartate
Image Source : PubChem
Function
- structural homologue of glutamate, with one fewer methylene (-CH2) group in the sidechain
- plays a role as the secondary excitatory neurotransmitter in the CNS
Glycine
Image Source : PubChem
Function
- a major inhibitory neurotransmitter in the spinal cord and brainstem
- coexists with GABA in many of these neurons
- exerts fast postsynaptic inhibition that is important for control of excitability of motor neurons, auditory processing, pain transmission in the dorsal horn, and other functions
- a coagonist of glutamate on NMDA receptors
D-Serine
Image Source : PubChem
Problems that are releated to Neurotransmitters
In order for Nuerotransmitters to function properly, they should be as follows :
- They should be transmitted at right place, right amount and at right timing
- They should be staying at the synaptic gap for right span of time
- They should be taken back fast enough at the right timing
Most of the problems that are related to Neurotransmitters are because those transmitters does not work as listed above. Common types of Neurotransmitter related problems can be listed as in this document as below.
- Neurons might not manufacture enough of a particular neurotransmitter
- Neurotransmitters may be reabsorbed too quickly
- Too many neurotransmitters may be deactivated by enzymes
- Too much of a particular neurotransmitter may be released
Distribution of Neurotransmitters in Brain
Image Source : Mapping neurotransmitter systems to the structural and functional organization of the human neocortex
Reference
- Common
- Acetylcholine
- GABA
- Glutamate
- Serotonine
- Dopamine
- Histamine
- Norepinephrine/Noradrenaline
- Epinephrine/Adrenaline
- Glycine
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