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The Addicted Brain Transcripts – Week 4
Video 4.1
Hello, today I’m going to talk about the inhalants. I won’t be able to discuss all of the
inhalants, but I’ll select some so that you will gain an understanding about this group of
substances.
Inhalants are liquids or gases, and the fumes are inhaled for their effects. They are found
in paints, glues, fuels, and many other products. These substances are legal, very available,
and they have rapid effects. Surveys show that a significant number of people use these
drugs.
Unfortunately, they are addicting and quite dangerous, particularly after long-term use.
The inhalants are a very diverse group of substances. It’s because they are classified not
on their pharmacological properties, not on the receptors that they stimulate, but on the
fact that they are volatile and gaseous. Therefore, they will have different properties and
mechanisms depending on the substance we are considering.
A first group includes the solvents, which are found in many materials including glue,
paints, paint thinners, and motor fuels.
Nitrous oxide, an anesthetic gas, is a widely abused inhalant. Outside of medical and dental
practices, it is found in whipped cream chargers, and it does cause laughing – hence its
name “laughing gas.”
Another group of inhalants include the alkyl nitrites found in room deodorizers.
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The Addicted Brain Transcripts – Week 4
Other inhalants are found in propellants like hairspray and in fuels like cigarette lighter
fluid.
This image shows the chemical structures of some of the inhalants. As I said, many are
readily available and include: toluene, which is very common, trichloroethylene, ether,
nitrous oxide, and others.
We can look at the inhalants as a class and make some general comments about their acute
effects. By acute I mean the first time effects.
First there is an excitation, which many refer to as a “rush.” This is then followed by
a depression. They produce an apparent drunkenness caused by disruption of mental
processes, loss of coordination, and slurred speech. They irritate the eyes and the lungs.
Higher concentrations can produce hallucinations, seizures, a coma, and even death.
A rare but lethal condition that can occur, even after a single first use, is something called
“sudden sniffing death.” It’s believed to be due to cardiac arrhythmias and stress. If this
occurs, it can be quite a shock to a family or group. These can be dangerous substances.
Anesthetics, another group of inhalants, produce a relaxation, anesthesia, and amnesia. One
can imagine that these effects would reduce stressful feelings felt by the user for whatever
reason. As we have said, stress is a common factor in drug use.
Having discussed the acute effects, we can now consider the effects that are found after
long-term use of the inhalants. General long-term effects of the use of inhalants are very
serious. They include brain damage resulting in shrinkage of some areas. Brain imaging
has shown this.
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The Addicted Brain Transcripts – Week 4
There is also damage to the bones, heart, kidneys and lungs, and an increase in the risk for
many other illnesses.
There is great concern about these toxicities given that inhalants are often abused by
children and adolescents.
How do inhalants work? Well as I mentioned, this is a very diverse class of drugs. And
because of that, there are many different mechanisms that we have to consider. Different
drugs have different mechanisms.
Toluene, a very commonly used inhalant found in paints and paint thinners, causes a
generalized depression of the brain, mainly by inhibiting excitatory neurotransmitter
receptors and by enhancing inhibitory neurotransmitter receptors. There may be actions at
other receptors as well.
When we consider the anesthetics, many enhance inhibitory neurotransmitter receptors
such as GABA-A and glycine receptors. Nitrous oxide is also thought to inhibit the
excitatory neurotransmitter receptor, the NMDA receptor.
So it is clear that these substances have a variety of actions, although for some there
are common themes in their actions. A common theme is the reduction or blockade of
excitation, and the enhancement or the increasing of inhibition at synapses in the brain.
Treatment is, of course, available for those abusing inhalants. Because of the serious
nature of the long-term effects of the drugs, stopping use is obviously beneficial.
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The Addicted Brain Transcripts – Week 4
Although treatment is available, there are no proven treatment medications specific for
inhalant abuse at this time. Therefore, an important approach is to treat the symptoms
and signs that occur with each specific inhalant in each patient, including counseling with
education about the substances.
As with many drug abusers, there are often co-existing mental or physical problems in a
given patient. Treatment programs for the addict should include addressing these other co-
existing mental and physical disorders.
We can close by restating what I said at the beginning of the lecture. Inhalants are easily
obtained, easily used, but addicting and very toxic. Cessation of use is most important.
Please don’t forget to examine the review questions for this lecture.
Video 4.2
Hello. Today we’re going to talk about a substance that most of us use every day. And
that substance is caffeine. Caffeine is well known to be a mild stimulant. Many people
take it in the morning to “get themselves going” as they say. It is perhaps the most widely
used psychoactive drug in the world. Psychoactive means that it alters the way your
mind functions. It's found in a lot of plants, and there is evidence that it produces abuse,
tolerance, dependence, and addiction.
Caffeine is found in coffee, tea, sodas, chocolate, energy drinks, and other things.
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The Addicted Brain Transcripts – Week 4
If you're used to taking caffeine all the time, and you haven't had it for a day or so, you
probably will experience some withdrawal. At that time, the effects of caffeine could be
calming because you're satisfying the withdrawal syndrome. But if you're having caffeine
frequently and you're taking higher doses, you may very well experience more severre
effects including: restlessness, nervousness, insomnia, urination, G.I. disturbance, muscle
twitching, a fast heart rate or tachycardia, and other things.
After prolonged daily use of caffeine, and after stopping it abruptly or reducing its use
significantly, the following may occur within 24 hours. Headache, fatigue or drowsiness,
a dysphoric or unpleasant mood, depression, irritability, you may have difficulty
concentrating, and in extreme conditions perhaps nausea or vomiting, which are rare.
It is believed that the effects of caffeine intake and the signs and symptoms of withdrawal
can cause significant distress or impairment in various areas of your life including social
and occupational activities. A survey revealed that 14% used caffeine despite harm and
despite advice to stop or reduce its use. 45% reported failed efforts to control its use. Thus,
caffeine has many of the properties of other drugs that are abused and cause addiction.
You know that drugs of abuse are typically associated with altering a specific
neurotransmitter system in brain. What neurotransmitter does caffeine interact with?
Well it is a neurotransmitter called adenosine. Caffeine is an antagonist at two of several
adenosine GPCR receptors. Ultimately, it also increases dopamine activity.
Because caffeine is an antagonist of adenosine, caffeine's actions are opposite to those
of adenosine. Adenosine is involved in inhibiting neurotransmitter release, reducing
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