- Opioids are a really fascinating class of drugs, because they have multiple effects on the body.

(upbeat music) Opioids can work to help our brain diminish pain signals.

So there are receptors that these opioids bind to which are expressed throughout the spinal cord.

An opioid acting at an opioid receptor in the spinal cord can help suppress or inhibit painful stimuli from reaching the brain.

We know that opioids are also used for recreational purposes, for the high or the euphoria that they can produce.

And this is caused by opioids acting at receptors within the limbic region of the brain.

We know that opioids working in this limbic region can cause the release of another neurotransmitter called dopamine in a region of the brain called the nucleus accumbens.

And that dopamine release is associated with feelings of reward, euphoria, and pleasure.

Opioids are a class of drugs that can produce what's called tolerance.

So tolerance is an adaptation in your body where you need to take an increased dose of the compound in order to achieve the same effect.

If someone was using morphine or another opioid medication for pain relief, over time, taking the same amount of drug actually leads to less and less pain relieving efficacy.

So the person would have to then increase their dose over time.

One of the things that we have found helps to predict the abuse liability of a drug or the abusive potential of a drug is how quickly it can reach the brain to cause that release of dopamine in the nucleus accumbens, fentanyl is an expert at reaching the brain very quickly and causing release of dopamine, and that's going to cause fentanyl to be very, very rewarding very quickly.

So it's an experience that a drug user would want to repeat.

And with repeated use, we know that this can facilitate the transition between maybe occasional use into that substance abuse addiction pattern of behavior.

And there's yet another area of the brain that opioids work in.

And this is in the respiratory centers in your brain stem.

So in between your brain and your spinal cord.

The cells in your brain stem are responsible for setting your respiratory rate.

So they are the ones that tell your lungs, it's time to inhale now, or you need to inhale more frequently or less frequently.

Opioid receptors, opioids as a class, are inhibitory.

They're suppressive.

And so if we suppress that respiratory rate, what happens is the time between inhalations becomes longer and longer and longer and can eventually just stop.

And this can lead to some of the consequences of opioid overdose, including overdose fatality.

Where we stand today, we know so much more about opioids, we know so much more about addiction or substance use disorder.

Can we start to put our effort and our time and our resources more toward analyzing the demand and what's underpinning that demand?

And that's gonna help us to better treat the people who are affected today in the present.

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