Researchers Identify Clues About Marijuana Effects
Scientists have been studying cannabinoids, substances that are chemically related to the ingredients found in marijuana, for more than two decades, hoping to learn more about how the drug produces its effects–both therapeutic and harmful. Marijuana has been reported effective in the treatment of multiple sclerosis, glaucoma, nausea caused by chemotherapy and wasting caused by AIDS. However, like all drugs, it also causes numerous unwanted side effects, including hypothermia, sedation, memory impairment, motor impairment and anxiety. Research on cannabinoids could someday yield new, more effective drugs or drug combinations.
At Temple University’s School of Pharmacy and Center for Substance Abuse Research (CSAR), one of only a few centers in the nation focused on the basic science of substance abuse, several researchers are investigating how cannabinoids produce pharmacological effects in rats.
One such study, “L-NAME, a nitric oxide synthase inhibitor, and WIN 55212-2, a cannabinoid agonist, interact to evoke synergistic hypothermia,” published in the February issue of the Journal of Pharmacology and Experimental Therapeutics, reveals how cannabinoids produce one of the drug’s most robust actions, hypothermia, or decreased body temperature.
According to lead author Scott Rawls, Ph.D., assistant professor of pharmacodynamics at Temple’s School of Pharmacy, “To operate at maximum efficiency, the body needs to maintain a stable, normal temperature. When the body’s temperature is altered, as in hypothermia, normal body functions, such as blood pressure and circulation, are impaired.”
Marijuana operates via two receptors in the body. One receptor, called CB1, is located in the brain and produces the drug’s psychoactive effects, including euphoria and dizziness. The other receptor, CB2, is found throughout the body and impacts the immune system. Substances in marijuana bind to one of these receptors and set off a chemical process that leads to an effect, such as hypothermia. Scientists have focused on this chemical process at the molecular level to pinpoint the exact molecules involved.
Knowing that the molecule nitric oxide (NO) plays an important role in the regulation of body temperature, the Temple researchers set out to determine what role it might play in cannabinoid-induced hypothermia. By combining a cannabinoid with a substance that blocked NO synthesis, they found that cannabinoid-induced hypothermia increased more than two-fold.
“This demonstrates the possibility that NO plays a part in regulating the impact of cannabinoids on body temperature and other cannabinoid-mediated actions,” said Rawls. “These findings could be helpful in determining the mechanisms that underlie some of the pharmacological actions of marijuana,” he added.
Rawls’ research team is currently investigating the impact of cannabinoids on other physiological systems, such as analgesia and movement, and the brain neurotransmitters that mediate those systems.
Scientists have been studying cannabinoids, substances that are chemically related to the ingredients found in marijuana, for more than two decades, hoping to learn more about how the drug produces its effects–both therapeutic and harmful.
Body Temperature and Cannabis: Does Pot Influence Body Heat?
The answer is yes, but barely.
Some people report getting the cold shakes when they get high, and others report feeling warm, making them ask “does consuming cannabis mess with our body heat one way or the other?” Don’t think that your body’s temperature regulation system is broken if you feel a sudden cold surge.
Cannabis products with varying degrees of THC, the psychoactive component of the plant, can affect your body temperature in a couple of ways, though most studies show pot is unlikely to cause a significant change unless you use it in very high doses.
In general, high doses of cannabinoids can lower body temperatures, with lab animals showing consistent decreases in temperatures following exposure to THC. There’s also some research which suggests it’s possible to become tolerant to the heat loss effects of THC, but only in female rats after four days, so the jury is still out on long-term effects in the human population.
There’s also some research which suggests it’s possible to become tolerant to the heat loss effects of THC, but only in female rats after four days, so the jury is still out on long-term effects in the human population.
How Cannabis Influences Body Temperature
Cannabis is a substance that affects people in a lot of different ways, with side effects ranging from dry mouth and red eyes to dizziness and paranoia. According to a 2017 study comparing the effects of THC and synthetic cannabinoids on lab rats, one of the primary effects of THC in lab animals is lower body temperature,
The hypothermia that results from THC is produced by certain cannabinoid receptors in the central nervous system, the research reported, while noting the effects of cannabinoids on body temp are considered “relatively straightforward.”
Researchers surgically implanted transmitters measuring body temperature or blood pressure into groups of rats. Then they injected THC and synthetic cannabinoids into the rats, and then monitored them for three hours.
After about 30 minutes, both THC and the synthetic cannabinoids resulted in decreases in body temperature. This was dependant on the dose they were given. Although they didn’t reach their lowest point until about 90 minutes.
A 2008 study from Brain Research tested how THC affected locomotor (body movements), brain, muscle and skin responses in rats. The animals were given three widely varying doses and then their responses to stimuli, including a tail pinch and social interaction, were compared to control subjects.
Lowest Temperatures Follow the Largest Doses
iStock / Olena Kurashova
After socializing and getting pinched, the control rats showed an increase in brain and muscle temperature. The rats given THC at any dose showed lowered brain and muscle temperature, though clinical hypothermia was seen only following the largest dose. In fact, the temperature effects of THC at lower doses was similar to a response from diazepam, a medication used to treat anxiety disorders.
Another study, published in the Journal of Pharmacology and Experimental Therapeutics, looked at two receptors in the body — one, called CB1, which is in the brain, and the other, CB2, which is found throughout the body — to untangle the chemical process at the molecular level that leads to certain marijuana side effects, including hypothermia.
The researchers, from Temple University, looked at the molecule nitric oxide and discovered that when they attached a cannabinoid with a substance that blocked nitric oxide from being synthesized, hypothermia more than doubled in rats. The study authors noted in a statement their results demonstrated “the possibility that (nitric oxide) plays a part in regulating the impact of cannabinoids on body temperature and other cannabinoid-mediated actions.”
CBD Found to Not Alter Body Temperature
By contrast, CBD does not appear to alter body temperature. Results reported in a 2011 review published in Current Drug Safety, suggest that CBD is non-toxic and does not affect heart rate, blood pressure, and body temperature, and also doesn’t affect the gastrointestinal tract or alter psychological functions.
Furthermore, a 2017 study reports that CBD treatment of up to two weeks had no effect on blood pressure, heart rate, body temperature, glucose and other levels. CBD, in general, has fewer side effects than products with THC, according to a host of research.
How Does the Body Regulate Heat?
The body has a brilliant system for regulating temperature that balances heat production with heat loss. This process is coordinated by the hypothalamus, a part of the brain that directs a number of body functions, including the operation of the nervous system.
Similar to a thermostat, the hypothalamus regulates temperature, with the goal of maintaining homeostasis. This means keeping the body temperature around 98.6 degrees Fahrenheit. It does this in response to multiple factors, both internal and external. For example, things like spicy foods we eat, the stress we go through and the heat outside. The hypothalamus doesn’t work alone — it coordinates with skin, sweat glands and blood vessels, the “vents, condensers and heat ducts of your body’s heating and cooling system.”
Marijuana and cannabinoids are known to have a strong effect on the hypothalamus’ regulatory functions, so it makes sense that they would affect the body’s temperature.
Any body-temperature changes caused by marijuana are usually mild and pass quickly. If you feel chilly, it might be a good time to grab a blanket and cuddle up. Smoking likely won’t cause any significant issues related to body heat, but if uncomfortable symptoms persist, you may want to get checked out by a medical professional.
Weed with varying degrees of THC can affect your body temperature in a couple of ways. Most studies show pot is unlikely to cause a significant change.