Understanding Excitatory and Inhibitory Neurotransmitters

Excitatory Neurotransmitters

Neurochemicals that increase the likelihood that a neuron will fire an action potential.

Excitatory Postsynaptic Potential (EPSP)

A voltage change due to a neurotransmitter that increases the chances that a neuron will fire an action potential.

Inhibitory Neurotransmitters

Neurochemicals that decrease the likelihood that a neuron will fire an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A voltage change due to a neurotransmitter that decreases the chances that a neuron will fire an action potential - slight hyperpolarization.

Synapse

Space between two neurons.

Synaptic cleft/gap

Narrow space between presynaptic neuron and postsynaptic dendrite.

Neurotransmitters

A chemical messenger in Nervous System, stored in vesicles, that travel across the synapse from one neuron to the next.

Dopamine (DA)

Function: Pleasure/Reward, Involved in drug addiction, Voluntary Movement, Learning, Attention, Emotion.

Acetylcholine (ACh)

Function: Memory, Movement (between motor neurons and muscles), Learning, Attention, Sleep.

Serotonin (5-HT)

Function: Emotion, mood, Sleep, arousal, Appetite.

Norepinephrine (NE)

Function: Mood, Sleep, Learning, Eating, Control alertness and arousal, Fight or flight.

Glutamate

Function: Excitatory messages, used by more neurons than any other neurotransmitter, Long-term memory and learning.

GABA

Function: Sleep, Movement.

Endorphins

Function: Inhibits pain signals and regulates pleasure, released in response to pain or vigorous exercise.

Substance P

A neuropeptide that produces pain.

Lack of Dopamine

Linked to Parkinson's Disease, characterized by difficulty initiating movement and tremors.

Excess Dopamine

Linked to Schizophrenia.

Lack of Acetylcholine

Can't contract muscles (paralyzed), linked to Alzheimer's disease.

Excess Acetylcholine

Can cause muscle convulsions.

Lack of Serotonin

Linked to depression, eating, sleep disorders, and aggression.

Excess Serotonin

Can lead to headaches, anxiety.

Lack of Norepinephrine

Can depress mood.

Excess Norepinephrine

Can cause anxiety, agitation, mania.

Lack of Glutamate

Problems in making or using glutamate have been linked to many psychological disorders.

Excess Glutamate

Can lead to migraines, seizures, insomnia.

Lack of GABA

Linked to anxiety disorders, seizures, tremors.

Excess GABA

Can lead to over relaxation and sedation.

Problems With Neurotransmitters

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.