Marijuana is produced by the cannabis plant, which is native to Asia but is now grown throughout the world. Individuals use marijuana for both its psychoactive, euphoria-inducing properties and its ability to relieve pain.
Chemicals produced by the cannabis plant are commonly known as cannabinoids. The two primary cannabinoids that occur naturally in the cannabis plant are THC – the psychoactive compound in marijuana – and CBD, which does not cause the sensation of being high.
Many marijuana users say they take it to treat pain, suggesting that readily available cannabinoids could potentially be used to offset the use of opioids such as morphine and oxycodone that are commonly used in pain treatment. A safer, natural alternative to opioid painkillers would be an important step toward addressing the ongoing opioid epidemic.
Intriguingly however, research suggests that cannabis use could also lessen the need for opioids directly by interacting with the body’s own natural opioid system to produce similar pain-relief effects.
I am a neuropharmacology scientist who studies both opioids and cannabinoids as they relate to pain treatment and substance abuse. My research focuses on the development of drug compounds that can provide chronic pain relief without the potential for overuse and without the tapering off of effectiveness that often accompanies traditional pain medications.
How opioids work
Our bodies have their own built-in opioid system that can aid in managing pain. These opioids, such as endorphins, are chemicals that are released when the body experiences stress such as strenuous exercise, as well as in response to pleasurable activities like eating a good meal. But it turns out that humans are not the only organisms that can make opioids.
In the 1800s, scientists discovered that the opioid morphine – isolated from opium poppy – was highly effective at relieving pain. In the last 150 years, scientists have developed additional synthetic opioids like hydrocodone and dihydrocodeine that also provide pain relief.
Other opioids like heroin and oxycodone are very similar to morphine, but with small differences that influence how quickly they act on the brain. Fentanyl has an even more unique chemical makeup. It is the most powerful opioid and is the culprit behind the current surge in drug overdoses and deaths, including among young people.
Opioids, whether naturally produced or synthetic, produce pain relief by binding to specific receptors in the body, which are proteins that act like a lock that can only be opened by an opioid key.
One such receptor, known as the mu-opioid receptor, is found on pain-transmitting nerve cells along the spinal cord. When activated, mu-receptors tamp down the cell’s ability to relay pain information. Thus, when these opioids are circulating in the body and they reach their receptor, stimuli that would normally cause pain are not transmitted to the brain.
These same receptors are also found in the brain. When opioids find their receptor, the brain releases dopamine – the so-called “feel-good” chemical – which has its own receptors. This is in part why opioids can be highly addicting. Research suggests that these receptors drive the brain’s reward system and promote further drug-seeking. For people who are prescribed opiates, this creates the potential for abuse.