Neurotransmitters - is in.

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Transcript Neurotransmitters - is in.

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Neurotransmitters are involved in physical processes,
such as muscle contractions, as well as,
psychological processes, such as thoughts and
emotions. Excesses or deficiencies in
neurotransmitters have been linked to some
psychological disorders, such as depression and
The neurotransmitter acetylcholine (ACh) controls
muscle contractions, especially those controlled by
the autonomic nervous system. The drug curare (a
poison) attaches to the receptor sites on muscles,
blocking the receptor sites, preventing acetylcholine
from acting which will cause paralysis.
Dopamine is involved in voluntary movements, learning and memory, and
emotional arousal. Schizophrenia is characterized by hallucinations and
disturbances of thought and emotion. These symptoms have been linked to too
much dopamine being released in the brain. In comparison, a lack of dopamine
in the brain has been linked to Parkinson’s disease, which is characterized by
muscle tremors and decreased mobility.
Noradrenaline helps to control alertness and arousal. It accelerates heart rate,
affects eating, and is linked with activity levels, learning, and remembering.
Excess and deficiencies have been linked to mood disorders. Stimulants, such
as cocaine and amphetamines (eg speed) facilitate the release of noradrenaline
and prevent its reabsorption (reuptake) keeping it in the synaptic cleft for longer
periods of time, thus increasing the firing of the neurons.
Serotonin affects mood, hunger, sleep and arousal. Deficiencies in serotonin are
involved in obesity, depression, insomnia, alcoholism, and aggression. Drugs
that block the reuptake of serotonin help in depression. By blocking reuptake,
the neurotransmitter stays in the cleft longer allowing for more of the
neurotransmitter to attach to the receiving neuron.
Endorphins inhibit pain. They act as the body’s “natural painkiller” and produce the
same effects that painkilling drugs such as morphine do.
How Drugs and Other Chemicals Alter
Drugs can affect neural communication by either causing neurons to
fire or by keeping them from firing.
Drugs that “excite” neurons and cause them to fire are called
Agonists either (1) attach themselves to receptor sites and “act”
like neurotransmitters, mimicking their effect or (2) block the
reuptake of the neurotransmitters, keeping the neurotransmitter
in the cleft for longer thus intensifying its effect.
Drugs that “inhibit” a neuron from firing are called antagonists.
Antagonists either (1) keep the neurotransmitters from being
released or (2) they block the receptor sites on the receiving
neuron but do not create the effects of the neurotransmitter.