Acetylcholine (ACh)
Present in the CNS and PNS
Enables muscle action, learning, and memory
All activity requires this
Deterioration is associated with Alzheimer’s disease
Glutamate
Main excitatory neurotransmitter
Involved in memory
Enhances learning and memory by strengthening synaptic connections
Overexpression leads to seizures and migraines due overstimulation of the brain
GABA (gamma-aminobutyric acid)
Main inhibitory neurotransmitter
Associated with various anxiety-related disorders
Undersupply links to seizures, tremors, and insomnia
Dopamine
Relates to the anticipation of pleasurable or rewarding activities
Influences movement, learning, attention, and emotion
Oversupply leads to schizophrenia
Undersupply leads to tremors and decreased mobility in Parkinson’s disease
Serotonin
Affects mood, hunger, sleep, and arousal
Low levels lead to depression
Some drugs that raise the levels are used to treat depression
Endorphins
Neurotransmitters that influence the perception of pain or pleasure
Natural painkiller and reward
Oversupply of opioid drugs will suppress the body’s natural supply
Epinephrine (Adrenaline)
Both a neurotransmitter and a hormone
Boosts energy
Involved in the “fight or flight” response
Norepinephrine (Noradrenaline)
Helps control alertness, arousal, and vigilance
Heavily involved in sleep cycle
Undersupply can cause depressive moods
Substance P
Involved in pain perception
Oversupply can lead to chronic pain