Neurotransmitter

Functions and characteristics

Acetylcholine (ACh)

• Activates motor neurons controlling skeletal muscles.
• Contributes to the regulation of attention, arousal, and memory.
• Some ACh receptors stimulated by nicotine

Dopamine (DA)

• Contributes to control of voluntary movement, pleasurable emotions.
• Decreased levels associated with Parkinson’s disease
• Over activity at DA synapses associated with schizophrenia
• Cocaine and amphetamines elevate activity at DA synapses

Norepinephrine (NE)

• Contributes to modulation of mood and arousal
• Cocaine and amphetamines elevate activity at NE synapses

Serotonin

• Involved in regulation of sleep and wakefulness, eating, aggression
• Abnormal levels may contribute to depression and obsessive compulsive disorder
• Prozac and similar antidepressant drug affect serotonin circuits

Endorphins

• Resemble opiate drugs in structure and effects
• Contribute to pain relief and perhaps to some pleasurable emotions
• “Runner’s high” may be associated with high endorphin levels