unit 1 chemical messengers

Neurotransmitters

Chemical messengers that transmit signals between neurons, allowing for communication within the nervous system. 

Released from the presynaptic neurons into the synaptic cleft, where they bind to specific receptor sites on postsynaptic neurons, initiating or inhibiting a neural impulse.

Excitatory Neurotransmitters

Chemicals released by neurons that increase the likelihood of an action potential occurring in the postsynaptic neuron.

Bind to receptor sites on the postsynaptic membrane, causes depolarization and making the neuron more likely to fire an action potential.

Acetylcholine (ACH)

A key neurotransmitter involved in thought, learning, and memory. Also involved in activating muscle action. (X) is excitatory and was the first neurotransmitter discovered.

Acetylcholine: Surplus / Deficit

Surplus: Severe muscle spasms

Deficit: Too little inside of the hippocampus has been associated with dementia & Alzheimer’s disease. As well as lack of muscle movement and control (Paralysis)

Dopamine

Pleasure chemical of the brain, released into the pleasure centers and is related to reward and motivation. (X) is Inhibitory

Is also associated with addiction, movement, and motivation. People generally repeat behaviors that lead to a release of this neurotransmitter.

Dopamine: Surplus / Deficit

Surplus: can lead to Schizophrenia most likely because of too many (X) receptors, may also lead to drug addiction

Deficit: associated with depression as well as muscular rigidity and tremors found in Parkinson’s disease.

Serotonin

Associated with feelings of well-being and happiness (regulation of emotion). Plays a role in the sleep cycle along with melatonin; also regulates intestinal movements. (X) is Inhibitory. 

Serotonin: Surplus / Deficit

Surplus: Hallucinations

Deficit: Depression (mood disorders), some anxiety disorders, suicide, and OCD.

Norepinephrine

Associated with response to danger, attention, and responding actions in the brain. (X) is Excitatory. May contract blood vessels to increase blood flow.

Norepinephrine: Surplus / Deficit

Surplus: Anxiety

Deficit: Depression & mental disorders

GABA

Slows things down, calms the CNS (acts as a natural tranquilizer). Contributes to motor control and vision. (X) is Inhibitory. Also increases sleepiness, decreases anxiety, alertness, memory, and muscle tension.

GABA: Surplus / Deficit

Surplus: Overly relaxed and sedated, can be to the point where normal reactions are impaired. May lead to sleeping and eating disorders.

Deficit: Anxiety, Seizures, Tremors, and Insomnia.

Glutamate

Involved with most normal operations of the brain. Includes thinking, long-term memory, and learning. (X) is Excitatory. Also the most common neurotransmitter in the brain.

Glutamate: Surplus / Deficit

Surplus: Overstimulates the brain and produces migraines or epileptic seizures.

Deficit: Impaired learning and memory, cognitive deficits.

Endorphins

Relieve pain and stress. Promotes feelings of pleasure and euphoria. (X) are Inhibitory. May be released in the brain during exercise, excitement, pain, and sexual activity.

Endorphins: Surplus / Deficit

Surplus: Body may not give adequate warnings about pain, and may encourage Artificial highs. 

Deficit: Increased pain sensitivity.

Substance P

Involved in the perception of pain, helps transmit pain signals from the body’s skin, muscle, and tissues to the CNS. Plays a role in promoting inflammation in response to injury; also involved in regulating emotion and social behavior.

Substance P: Surplus / Deficit

Surplus: Increased pain sensitivity, chronic pain, inflammation (things like arthritis) or IBS. Mood disorders like anxiety, depression, and stress-related disorders.

Deficit: Reduced pain sensitivity, can reduce the body’s ability to detect harmful stimuli. Impaired healing response; slow down recovery from injuries or wounds.