Neurotransmitters: Acetylcholine, Dopamine, Glutamate

• More than 100 chemicals act as neurotransmitters throughout the brain and body.
• These chemicals affect thought, feeling, and behaviour.
• Actions like waving, eating, or falling asleep involve different neurotransmitters flowing across synapses.

Acetylcholine (ACh)

• Involved in voluntary motor control.
• Found in neurons of the brain and synapses connecting to muscles and organs.
• Activates muscle movements and regulates attention, learning, sleeping, dreaming, and memory.
• Deterioration of ACh-producing neurons is associated with Alzheimer’s disease, which causes severe memory impairments.

Dopamine

• Regulates motor behaviour, motivation, pleasure, and emotional arousal.
• Plays a role in drug addiction due to its involvement in motivated behaviours, like seeking pleasure.
• High levels are linked to schizophrenia, while low levels are linked to Parkinson’s disease.

Glutamate

• The major excitatory neurotransmitter in the brain.
• Enhances information transmission between neurons.

GABA (gamma-aminobutyric acid)

• The primary inhibitory neurotransmitter in the brain.
• Prevents the firing of neurons.
• Too much glutamate or too little GABA can cause neurons to become overactive, leading to seizures.

Norepinephrine

• Involved in states of vigilance and heightened awareness of dangers.

Serotonin

• Involved in regulating sleep, wakefulness, eating, and aggressive behaviour.
• Low levels of both norepinephrine and serotonin are linked to mood disorders like depression.

Endorphins

• Act within the pain pathways and emotion centres of the brain.
• Endorphin is a contraction of endogenous morphine, an internally produced substance with similar properties to morphine.
• Dull pain and elevate moods.
• Release of endorphins in the brain can explain the "runner’s high" experienced by athletes

Neurotransmitter Imbalances

• Typical functioning requires a delicate balance of neurotransmitters.
• Imbalances can affect behaviour.
• The brain may not produce enough serotonin, which contributes to depressed or anxious moods.
• Smoking, alcohol, or drugs alter the balance of neurotransmitters in the brain.
• LSD is structurally similar to serotonin, so it binds easily to serotonin receptors in the brain, producing similar effects.

How Drugs Mimic Neurotransmitters

• Drugs can affect the nervous system by increasing, interfering with, or mimicking neurotransmitters.

Agonists

• Increase the action of a neurotransmitter.

Antagonists

• Diminish the function of a neurotransmitter.
• A drug that activates the neurotransmitter by binding to a receptor is an agonist.
• A drug that prevents the neurotransmitter from acting or lessens its effect is an antagonist.