Understanding the evolution of cannabinoids helps veterinarians appreciate the unique role cannabis can play in the medical treatment of dogs. It also suggests some other, more controversial possibilities.
Written by Diana Trimble
It’s generally accepted by biologists, if hotly contested by creationists, that five hundred million years ago or so, the Sea Squirt arrived on the evolutionary scene. As its somewhat rude common name would suggest, this wasn’t exactly the most sensational of harbingers. After all, the Sea Squirt is a lowly feeder that lives at the bottom of the ocean. Despite the fact that it’s technically a distant relative for all us vertebrates, its largely immobile behavior more closely resembles that of a simple sponge. (I once had a housemate of whom much the same could be said, but I digress…)
There’s something to be said for the slow burner, and perhaps it is, ahem, high time that credit is given. As Maurice Elphick, Professor of Animal Physiology and Neuroscience at Queen Mary University of London, demonstrated in works such as “The Evolution and Comparative Neurobiology of Endocannabinoid Signaling,” it was none other than the Sea Squirt that first had the brilliant impulse to create cannabinoids, and establish them at the origins of the developing central nervous system, thus ensuring that all ensuing vertebrates would have tetrahydrocannabinol (THC) and cannabidiol (CBD) receptors.
Now that’s what I call forward thinking! You go Sea Squirt!
The cannabinoids’ resulting crawl through evolution was extraordinarily comprehensive; it was also excruciatingly slow. Eventually, specialized sub-species were able to experience both psychoactive and physiological effects from cannabis and its derivatives.
Even more than humanity, it’s man’s best friend, the dog, that is outfitted with endocannabinoid receptors galore. As one impressive slide in Dr. Richter’s presentation at the 2016 Emerald Cup in Santa Rosa, California showed, “Studies from the 1970s found the dog to have the highest concentration of membrane receptors for THC in the cerebellum, more than any other species measured.”
Perhaps this can be explained by the early origins of dogs, which go back to approximately sixty million years ago. Although the earliest primates popped up around the same time, the order was still comprised of both Prosimians (e.g. bushbabies, lemurs) and Anthropoids (this is where we start to come in) until twenty millennia had passed. The split between monkeys and humans didn’t occur for another fourteen million years.
Simply put, humans, dogs and cannabinoid receptors developed in symbiotic harmony right up to the present day.
However the use of cannabis for dogs – whether medicinal or recreational – has never really been considered. Until now.
Visionary veterinarians, like Dr. Richter, have pioneered the application of various cannabis products for pets. As he explained, just as with humans there are a variety of ailments that can be relieved, controlled, or even eradicated by cannabis.
Medicinal benefits for canines are similar to those in humans: nausea control, appetite stimulation, anxiety reduction, anti-inflammatory effects, seizure reduction, relief of sleep disorders, and resistance to cancer, as well as reducing side-effects of some pharmaceutical medicines.
As far as the risks, those seem to be reasonable, according to research presented by Richter.
Even so, Richter said it’s crucial to involve veterinarians in any decision to treat a pet with cannabis. It may be hard to kill a dog with cannabis, but you could certainly cause it to suffer by giving it too much. In some cases, stomach pumping and treatment with charcoal may be required.
In Richter’s practice, he avoids mishaps by helping pet-owners create carefully measured syringes of cannabis oil (for oral ingestion). Dosages start as low as possible and are gradually increased to find the optimum level of relief.
But what if your vet is unsympathetic to the notion of cannabis-based treatment? What if he is supportive, but can’t say so?
Indeed, the American Veterinary Medical Association (AVMA) has stated that the protections from prosecution that exist for physicians recommending cannabis to their human patients in certain states, “do not apply to veterinarians, for whom it is illegal in every state to prescribe or recommend marijuana to treat a patient.”
Accordingly, the ASPCA’s webpage on “marijuana” describes cannabis as toxic to dogs, cats, and horses. It doesn’t allow for any medicinal, or recreational, attributes and gives a phone number for Poison Control “if your pet ingested this plant.”
So, has anyone ever actually been prosecuted for giving their pets cannabis?
I was relieved to find no evidence of a veterinarian being prosecuted, although it’s possible. Owners, on the other hand, should consider the 2015 “animal cruelty” case against one aptly named Bruce Blunt.
The Chicago PD took Binna, Mr. Blunt’s pet chameleon, into protective custody after PETA reported a video posted on Facebook which showed Blunt blowing smoke into his “sometimes aggressive” pet reptile’s mouth. His defense; the creature seemed becalmed by the second-hand fumes. As the judge noted in his acquittal decision “the chameleon did not change color,” indicating it was not distressed, and did not suffer any ill effects.
I contacted PETA to ask if giving cannabis to dogs was tantamount to animal abuse. I received this response, attributed to Senior Vice President of Cruelty Investigations, Daphna Nachminmovitch, “If the proper administration of marijuana can truly relieve a dog’s pain, then they should be given the same consideration that humans in pain are given, with regular doses to help reduce their misery. It’s entirely a different matter to amuse oneself by getting the cat drunk or the dog high.”
Encouraged by PETA’s stance, I decided to see how things stood in a pro-canna state like Colorado. I was surprised to see the popular article, published in the Denver Post in 2013, “Pot and Pets: For Them a High is Dangerous – So Stash that Stash,” by veterinarian Stephen M. Sheldon.
In this, Dr. Sheldon focused on the dangers of leaving one’s herb within Fido’s reach, and stated that “It is unnatural for animals to be intoxicated. They’re uncomfortable with it.”
Not according to the seminal work of Ronald K. Siegel whose 1989 book, “Intoxication: The Universal Drive for Mind-Altering Substances,” presented a persuasive case for pan-species partying. Far from being “unnatural,” many animals positively crave a good buzz. To quote Siegel, “…animals have guided us to a variety of sources of drugs throughout the ages. In AD 900 an Abyssinian herder noticed that his animals were energized after eating the bright red fruit of a tree that would later be named coffee. A shepherd in Yemen discovered the popular Middle Eastern stimulant khat, similar to amphetamine, by watching goats run wild after chewing the leaves…. After sampling the numbing nectar of certain orchids, bees drop to the ground in a temporary stupor, then weave back for more. Birds gorge themselves on inebriating berries, then fly with reckless abandon. … Elephants purposely get drunk on fermented fruit.”
If medicinal approval of cannabis for dogs is on the horizon, can acceptance of their recreational use be far behind? Clearly, more research is needed.