Our bodies have natural drugs and pathways
that can make us feel happy, or relieve pain.
One natural drug group are the endorphins.
These chemicals are oligopeptides that activate
the body’s opiate receptors, causing inhibition
of pain signals and feelings of euphoria.
These opiate receptors are the same receptors
that respond to morphine and heroin.
Imagine you are stung by a bee.
Your pain sensing neurons will send substance
P, a pain neurotransmitter, to receptors on
neurons that send the message to your central
nervous system.
It’s important that you realize there is
a source of pain, but you don’t want the
pain to last forever.
Endorphins will be released and bind with
opiate receptors on the pain signaling neuron.
This will inhibit the transmission of substance
P into the synapse.
This blocks the pain signal for reaching the
central nervous system.
This will help dull the pain of the bee sting
and eventually, the pain will subside as the
injury heals.
Anesthetics are substances that induce insensitivity
to pain by interfering with neural transmission
between areas of sensory perception and the
central nervous system.
Instead of just relieving pain like endorphins,
the anesthetics will completely block pain.
There are a wide variety of anesthetics that
work in different ways.
The two broad categories of anesthetics are
local and general anesthesia.
Both categories are reversible as long as
the amounts are carefully administered.
Local anesthesia affects only a smaller area
of the body and usually the person is still
conscious.
General anesthesia will usually render the
person unconscious or semi-conscious if they
need to be monitored more closely during surgery.
The action of general anesthesia is not fully
understood, but local anesthesia works in
a similar way as endorphins.
Local anesthesia will block pain signals.
Novocaine, a local anesthetic used in dentistry,
will inhibit pain signals by blocking the
sodium channels that are needed to start an
action potential in the pain signaling pathway.
This will prevent the pain from reaching the
central nervous system.
Other drugs will affect the brain and personality
instead of just blocking pain.
Different kinds of psychoactive drugs can
affect the brain by either increasing or decreasing
post-synaptic transmission.
Excitatory drugs include, nicotine, the addictive
ingredient of tobacco, cocaine, and amphetamines
which are a group of synthetic drugs.
Inhibitory drugs include alcohol, tetrahydrocannabinol
or THC from the Cannabis sativa plant and
benzodiazepines like Valium.
Stimulant drugs will mimic the stimulation
provided by the sympathetic nervous system.
This is your fight or flight system, which
means you would feel more alert and energetic.
Your heart rate would increase as well as
blood pressure and body temperature.
stimulants can be mild like the caffeine in
coffee or theobromine in chocolate, and even
nicotine has a relatively mild stimulating
effect.
Strong stimulants include cocaine, Adderall
and MDMA, better known as ecstasy.
When new medical drugs are being developed,
they must go through rigorous testing before
they are available to the public.
This could take many years.
Researchers need to establish both the appropriate
dose and administration and make sure that
side effects are mild and safe.
However, in the case of very serious terminal
illnesses, like AIDS or terminal cancer, a
patient may be able to lobby for the use of
drugs that haven’t been fully tested.
The risk of the drug may be outweighed by
the serious illness and short amount of time
they may have left.
There are many drugs that can be addictive.
The American Psychiatric Association defines
addiction as a chronically relapsing disorder
that is characterized by three main elements:
compulsion to seek and take the drug, loss
of control in limiting intake, and emergence
of a negative emotional state when access
to the drug is prevented.
Addiction can be affected by several factors
as well.
Some people have a genetic predisposition
for addiction.
The gene DRD2 has alleles that correlate with
alcohol consumption.
Our social environment also affects propensity
for addiction.
Poverty, peer pressure, mental health issues
and traumatic experiences all could contribute
to addiction.
Lastly dopamine secretion from addictive drugs
like heroin, cocaine, nicotine and alcohol
can cause physical changes in the brain that
make the user more likely to depend on the
drug to feel normal.
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