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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