marijuana botanical illustration

Cannabis sativa

The Drug Enforcement Agency this week said that there are no accepted medical uses for marijuana, leaving it on the list of dangerous drugs like heroin. The scientific community continues to find proof of wide-spread anecdotal reports about the medical value of marijuana. A recent report describes a mechanism that explains how marijuana might improve the appetite of chemo patients. This, along with pain reduction in glaucoma and multiple sclerosis, is one of the most common medical uses for marijuana.

The New York Times reports on a study [link is to abstract; the paper will be published later] by researchers at the University of California Irvine and the Italian Institute of Technology in Genoa. The abstract tells us that the scientists were studying the endocannabinoid system in rats. The endocannabinoid system is a set of nerve receptors and related body chemicals that deal with appetite, pain-sensation, mood and memory. The interesting thing about the nerve receptors is that they respond to cannabinoids, one of the components of marijuana.

I have a special interest in this research because my brother Michael was a major contributor to the field. When he first started working in the field of pain transmission in the body, he explained to me that the body creates chemicals that lock into the receptors on nerve endings and prevent the transmission of pain. Nature creates other chemicals that fold up in a way that permits them to lock into the same receptors and prevent the transmission of pain. These include the opioids, like morphine, and the cannabinoids. The receptors that respond to cannabinoids are part of the endocannabinoid system. The principal difference is that the opioids work in the central nervous system, so they depress breathing and peristalsis. My brother said that the cannabinoids generally work further out in the pain transmission nerves, before they get to the spinal column. They don’t have those ugly side effects.

The NYT describes the research this way:

Among rats given liquid diets high in fat, sugar or protein, the ones who got the fatty liquid had a striking reaction: As soon as it hit their taste buds, their digestive systems began producing endocannabinoids, chemicals similar to those produced by marijuana use.

The new research suggests that the focus might be shifted to endocannabinoids in the gut, which could alleviate side effects in the brain.

In the rat studies, the researchers injected a cannabinoid-blocking drug into the intestines of the rats and found that they lost interest in the fatty food. “The effect is remarkable,” Dr. Piomelli said. “They are no longer interested in feeding. They stop completely. We were amazed.”

The clear implication of this result is that increasing endocannabinoids in the intestines of a chemo patient will increase the desire for food. I believe the technical name for this phenomenon is “munchies”, though that may date me.

The NYT article is focused on the implications for obesity. A lot of people don’t seem to be able to control their eating, leading to weight gains, even to morbid obesity. Many of them claim that they can’t control their weight, and there is some support for this in the medical community. Perhaps in some cases their endocannabinoid systems are ramped up beyond those of other people.

The study tells us that infusing rat intestines with a cannabinoid blocker reduces the desire to feed on fat. That suggests the possibility of drugs to reduce eating behaviors. The NYT says there is one such drug, but it was withdrawn because of “…severe psychological side effects, including suicidal thoughts.“ Hopefully we can find another blocker with fewer side effects. Maybe you really can just eat one potato chip.

The DEA should be fine with cannabinoid blockers. It’s the chemo patients and people who need more cannabinoids who will suffer.