The Endocannabinoid System in Animals is Different than in Humans

Is it safe to use cannabis to medicate our pets?

It might surprise many pet owners to find out that the very same CBD that works for the human body could also have therapeutic applications for their furry friends. Research is only in its infancy, but remains promising. Interestingly, cats, dogs, and many other animals have something in common with their owners: an endocannabinoid system.

The endocannabinoid system is a relatively recent discovery. After seeing its list of vital physiological functions, this will come as a surprise. Since the 1990s, researchers have been digging into the many ways the endocannabinoid system regulates mood, memory, pain, inflammation, and appetite in humans. While most of the research to date focuses on the human endocannabinoid system,  what about other animals?

Researchers rely on laboratory animals, such as specially bred rats and mice, as an early phase of medical research. Still, beyond these applications, scientists know little about the endocannabinoid system of other vertebrates or invertebrates. While the endocannabinoid system of animals has many similarities to the human version, there are important differences. These differences impact cannabis for veterinary care so pet owners should take note.

Do all Animals Have an Endocannabinoid System?

Robert J. Silver, the Chief Medical Officer of RxVitamins, published “The Endocannabinoid System of Animals” in the journal Animals (2019). According to Silver’s research, there are few creatures who do not have an endocannabinoid system in some form or another.

So far, the only animals with no known endocannabinoid system include insects and a microscopic single-celled creature known as Phyla Protozoa. Otherwise, scientists believe creatures from all walks of life, including mammals, birds, fish, reptiles, and even nematodes, at the very least have a primitive endocannabinoid system.

All About the Endocannabinoid System in Animals

The endocannabinoid system has become a novel therapeutic target in human medicine. As per Silver’s educational summary on the subject, “there is still a paucity of information regarding the same benefits in animals, except for the laboratory animal species in which experimental studies have been performed.” Compared to what medical researchers have uncovered about the “human animal,” veterinarians and biologists know much less about the other creatures on earth.

In the most primitive forms, endocannabinoid systems are responsible for minimal regulatory actions. These basic endocannabinoid systems seem to only be responsible for the management of feeding behavior. In more evolved species, the system takes on more regulatory duties, which may include pain, memory, and reproductive activities.

Unsurprisingly, the mammalian endocannabinoid system is the most similar to the human endocannabinoid system. After all, humans are mammals. The endocannabinoid system of other mammals, like cats, dogs, and rodents, seems to operate (at least in the most basic terms) as the human system does. Furthermore, all mammals have CB1 and CB2 receptors.

Be Careful With Dogs and THC

There are important differences between animals, however. Some of these are significant for pet owners regarding the consumption of cannabinoid medicine for pets. Not all endocannabinoid systems are equal when it comes to cannabis. Pet owners and veterinarians need to understand the critical differences to keep animals safe.

One of these is the location and concentration of CB1 receptors in dogs. Both humans and dogs have CB1 receptors concentrated in the brain, but dogs have much higher concentrations. This is especially true in the cerebellum, brain stem, and medulla oblongata.

THC is a CB1 receptor agonist, and if dogs ingest it, their endocannabinoid system is quickly overwhelmed. With so many more CB1 receptors, dogs are at risk of THC overdose and death, through a condition known as static ataxia.

Therapeutic Applications of CBD for Pets

Market analysts expect the CBD pet industry to reach $1.16 billion by 2022 in the U.S. alone. Companies are banking on preliminary science to market veterinary applications for this non-intoxicating cannabinoid. Logically, if dogs, cats, and other furry-pets have a similar endocannabinoid system to humans, the public assumes there is a significant overlap in medical applications. But this is a potentially dangerous conclusion.

In his extensive piece for Animals, Silver takes the time to review the therapeutic targets of CBD for pets. Here are several of the most notable therapeutic applications of CBD for pets.

• Pain Relief: Naturally, all mammals produce endocannabinoids in response to inflammation and tissue injury. Some of these endocannabinoids help reduce the sensation of pain around the site of injury. If the endocannabinoid system is not functioning properly, pain regulation may not be effective. Cannabinoids, already established for pain relief in humans, could help regulate chronic nerve and inflammatory-related pain in pets.
• Anti-inflammatory Properties: Many cannabinoids have anti-inflammatory capabilities, especially cannabinoid receptor agonists. Considering inflammation is the basis for many chronic diseases, both in animals and humans, anti-inflammatories like CBD are a novel therapeutic target in veterinary applications.
• Reduce Anxiety and Stress: Some endocannabinoids exist to regulate stress and anxiety. According to Silver, in studies looking at stress, researchers discovered decreased levels of endocannabinoids. This may be why phytocannabinoids, like CBD, have anti-anxiety qualities. If CBD upregulates the number of natural endocannabinoids, it may, therefore, reduce stress.

The endocannabinoid system modulates the nervous and immune systems and other organ systems. It does this through a complex network of receptors and chemical signaling molecules to relieve pain and inflammation. It also modulates metabolism and neurologic function, promotes healthy digestive processes, and supports reproductive function and embryologic development.

A Word of Caution About Using Cannabinoids for Pets

Not all cannabinoids are safe for applications with pets. As detailed by Silver, scientists have already determined dogs are highly susceptible to toxic reaction, and possibly death, following THC exposures. At this time, dogs should not be medicated with THC.

In Silver’s analysis, “the psychoactive effects of THC are undesirable in all veterinary species.” While researchers are exploring ways to titrate THC for veterinary applications safely, it is strongly recommended that pet owners stick with CBD-only products.

Unlike THC, CBD is not a cannabis-receptor agonist so there is an assumption that it’s safe for consumption among cats, dogs, and other mammalian pets. The American Veterinary Medical Association is still cautioning against prescriptions for CBD by their members, but that hasn’t stopped many vets from incorporating it into their own practices. The hesitation about CBD in veterinary practice is the same for humans: a lack of clinical research.

For pet owners wanting to incorporate CBD into treatment plans for their furry friends, the best advice is to work with their veterinarian. While several preliminary studies prove CBD is well-tolerated by dogs, it’s still early days. There is a long way to go before veterinary science understands all possible interactions, long term effects, and therapeutic applications.

Extra precaution should be taken if your canine or feline companion is on other medications as, according to Silver, “no definitive objective study exists accurately and objectively, which defines the herb-drug interactions between CBD and selected pharmaceuticals in veterinary species.”

A vet can advise on whether CBD is a good fit based on the animal’s history and current medications. So always consult a professional before medicating your pet with cannabis.