The Endocannabinoid System in Dogs and Cats Explained
The first, and last word, should go to Professor Mechoulam, who sums up this concept and discovery with simple eloquence:
“By using a plant that has been around for thousands of years, we discovered a new physiological system of immense importance… We wouldn’t have been able to get there if we had not looked at the plant.”
Endocannabinoid System in Dogs & Cats Explained
The Endocannabinoid System (ECS) functions the same way in people as it does in dogs, cats and other animals. As a matter of fact, ALL mammals have an Endocannabinoid System. This includes horses, rabbits, monkeys, dolphins and elephants to name a few. A large amount of research is currently being undertaken around the world to find out how exactly the ECS might be utilized in the treatment of different chronic diseases.
Scientifically speaking, The Endocannabinoid System (ECS) is made up of neurons, endocannabinoids and cannabinoid receptors. We will try and break down the concept into simpler terms, as this is fascinating stuff, but requires some explanation for pretty much everyone who hasn’t studied neuroscience, including us!
There are nerve cells called neurons throughout the brain and body which are linked together by neurotransmitters. These neurotransmitters are molecules called agonists that move from one neuron to another through the minute space between them, which is called the synapse.
The agonists plug into neural receptors, causing a chain reaction. In the case of the endocannabinoid system, these receptors are called CB1 (Cannabinoid receptor 1) and CB2 (Cannabinoid receptor 2).
CB1 receptors are mainly found in the brain, with some in the liver, lungs, and kidneys. CB2 receptors are found throughout the body. There are more cannabinoid receptors in the brain than any other type of neural receptor.
A common analogy is that the agonists are keys and the receptors are locks. However, you can also think of the neurons as being like Lego blocks, with the studs* as agonists and the tubes* as receptors. The endocannabinoid system is a structure. It can only work if the blocks fit together. And as you’ll see, it’s essential that it does work! Endocannabinoid system sends signals within the brain and around the body:
Cannabinoids transmit signals from one neuron to another
CB1 = cannabinoid receptor 1. Location: Mostly brain
CB2 = cannabinoid receptor 2. Location: Body
The Endocannabinoid system in dogs is part of what maintains the natural balance in the body and it is usually stimulated by endocannabinoids which are produced internally. However, the endocannabinoid system can also be stimulated by external cannabinoids, including Cannabidiol (CBD) – the non-psychoactive compound found in cannabis sativa. The external stimulation from CBD is causing some big excitement in the medical world today.
The endocannabinoid system is activated by (surprise, surprise) cannabinoids. The cannabinoids naturally produced by the body, which are known as endocannabinoids; and the cannabinoids found in cannabis, which are known as phytocannabinoids.
The key and lock analogy mentioned above is based upon the CB1 and CB2 receptors only being activated by cannabinoids, not any other type of agonist molecule. The cannabinoid ‘keys’ are the only ones that will fit the receptor ‘locks’.
Phyto = prefix meaning a plant or plants
Endo = prefix meaning within or inside
Phyto-cannabinoids, also called classic cannabinoids, come from plants
Endocannabinoids come from inside the body
The CB1 receptors are activated by THC (tetrahydro-cannabinoid) – so when we talk about the ‘headrush’ effect caused by sativa-dominant, THC-heavy strains, there’s a literal quality to that statement!
The CB2 receptors are activated by CBD (cannabidiol), which is not psychoactive and more associated with cannabis strains (and pure CBD products) that give a relaxing, body-centric effect. This makes the location of, and difference between, the two receptors easy to remember!
CB1 = THC = head
CB2 = CBD = body
If you have ever wondered how CBD can be used to treat so many different types of illnesses, here is an explanation of how CBD can have a positive effect on the Endocannabinoid system in Dogs & Cats and how this can have a beneficial effect on so many other parts of the body.
What Is the Endocannabinoid System?
The Endocannabinoid system was first discovered by scientists who were carrying out research into why cannabis has the effect on people that it does, hence the name Endocannabinoid System. “Endo” is an abbreviation of endogenous, which refers to something that originates inside of the body. Cannabinoid is the term used to describe the compounds that are responsible for activating the endocannabinoid system.
The Endocannabinoid system is the biological system that is responsible for the effects that cannabis has, both the psychosocial and physical. It has also been discovered that the endocannabinoid system plays a major role in regulating many important functions within our pet’s body.
The endocannabinoid system regulates the body’s systems to maintain homeostasis: the state of balance necessary for healthy function. Homeostasis can be thought of as the narrow range of states within which bodies work as they should.
For example, the blood sugar levels, internal temperature, pH levels of blood, regulation of the amount of water and minerals in the body, and the removal of metabolic waste, are all governed by homeostatic processes.
A simple analogy is to think of the body as a house, and the endocannabinoid system as the caretaker inside. If the house is too hot, the caretaker opens the windows or turns on the air conditioning. If the house is too cold, the caretaker closes the windows and turns on the heating. If the house becomes dirty, the caretaker cleans it, but also knows when to stop cleaning it – you wouldn’t throw away all the rubbish and then start on the furniture.
Body = house
Endocannabinoid system = caretaker
Cannabinoids = messages the caretaker receives about what needs to be done
Most agonists only travel in one direction. Cannabinoids are unusual in that they can travel both ways between neurons. This is known as a negative feedback loop. It is what makes the ECS such an essential system for lifeforms. It tells the body when to begin a process (for example, sweating to cool down) but also when to stop it (otherwise we’d all be sweating constantly).
Bodies constantly make their own cannabinoids (endocannabinoids) to interact with their endocannabinoid system, ensuring that homeostasis continues.
If the body does not create enough endocannabinoids, it is thought that clinical endocannabinoid deficiency may occur. The theory is that this deficiency can be treated by introducing Phyto-cannabinoids, something that humanity has been doing with varying degrees of therapeutic success since before recorded history.
The reason cannabis can treat so many different conditions is that the endocannabinoid system is spread throughout the body and responsible for the correct functioning of so many different parts and aspects of it.
The Endocannabinoid system in dogs has recently become the subject of much scientific research, because of the many effects that it has on the body and the potential for using the stimulation of the system to treat disease. Scientists understand the basic functioning of the endocannabinoid system, but researchers are uncovering more new exciting therapeutic uses of the system daily.
Does the Body Produce Cannabinoids like CBD?
The body does indeed produce cannabinoids. Endogenous Cannabinoids are neurotransmitters produced within our bodies that bind to cannabinoid receptors in the brain, immune system, and elsewhere. Examples include anandamide, 2-arachidonoylglycerol (2-AG), n-arachidonoyl dopamine (NADA), and virodhamine (OAE).
Endocannabinoids perform differently to the more well-known neurotransmitters like serotonin, dopamine, and norepinephrine.
Dopamine, for example, is synthesized in advance, stored in the vesicle, and in response to stimuli, is released from the presynaptic cell, where it crosses the synapse, lands on the postsynaptic cell, and causes activation.
Endocannabinoids, on the other hand, are key components of cellular membranes that we manufacture on demand. Since endocannabinoids are hydrophobic, they cannot travel very far in the body and so their effects are localized.
Endocannabinoids also travel in the opposite direction to other neurotransmitters. They first leave the postsynaptic cell and end at the presynaptic cell where there are high concentrations of axons. Axons are responsible for the release of traditional neurotransmitters.
This allows the postsynaptic cell to control the flow of neurotransmitters coming from the presynaptic cell.
When was the endocannabinoid system discovered?
You might think that, since the ECS is so ancient, so vital, and so common in lifeforms, it would have been discovered long ago. You would be wrong. The endocannabinoid system was only confirmed in the form that we know it today (CB1 and CB2 receptors, triggered by two known endocannabinoids) in 1995.
- 1940 – CBD first isolated
- 1963 – CBD first synthesised
- 1964 – THC first synthesised
- 1988 – CB1 identified (in rats)
- 1991 – CB1 in humans successfully cloned
- 1992 – Anandamide, the first endocannabinoid, discovered in human brain
- 1993 – CB2 identified in humans and successfully cloned
- 1995 – 2-AG, the second endocannabinoid, discovered
The Phyto-cannabinoid CBD was first isolated in 1940, but not until 1963 did Professor Mechoulam and his team discover its chemical structure and successfully synthesize it. Their feat was replicated with THC a year later.
In 1988, the first cannabis receptor was identified; in 1993, the second. The first endocannabinoid, named anandamide, was only discovered in 1992 and the second, known as 2-AG (because only a handful of highly skilled individuals can easily pronounce 2-arachidonoylglycerol) followed in 1995.
What Are Cannabinoid Receptors?
Cannabinoid receptors are located on the surface of cells and they monitor the conditions outside of the cell. They transmit what they detect to the inside of the cell and that triggers the appropriate cellular response.
There are several types of cannabinoid receptors in the endocannabinoid system in dogs and other animals, but the two major ones are known as CB1 and CB2.
CB1 Cannabinoid Receptors
CB1 receptors are found throughout the body but are more concentrated in the spinal cord and the brain than anywhere else. CB1 receptors in the brain are found in the regions of the brain that control certain behaviours. For example, CB1 receptors have been found in the hypothalamus, which is the part of the brain that is responsible for regulating appetite. There are also CB1 receptors in the region of the brain that is related to emotions and memory, which is called the amygdala. CB1 receptors that are believed to able to control pain have also been identified in the nerve endings.
Benefits of activating the CB1 receptor include:
- Relieving depression [Ref]
- Increasing myelin formation [Ref]
- Decreasing intestinal permeability (Leaky Gut Syndrome) [Ref]
- Lowering blood pressure [Ref]
- Lowering anxiety [Ref]
- Reducing fear and paranoia [Ref]
- Increasing BDNF levels [Ref]
- Increasing PPARy expression [Ref]
- Reducing GPR55 signalling [Ref]
- Lowering prolactin [Ref]
While these are desirable effects for most people, CB1 receptor activation does not come without risks. These risks include:
- Lowered thyroid hormones [Ref]
- Reduced ability of the circadian timekeeper (SCN) to entrain to daylight [Ref]
- Decreased cognitive function (through decreasing acetylcholine, LTP, cAMP, and glutamate) [Ref]
- Increased anxiety for an individual going through alcohol withdrawal [Ref]
- Constipation [Ref]
- Increased liver fat [Ref]
- Increased food intake [Ref]
- Less burning of fat for energy [Ref]
- Neurological symptoms such as depersonalization, paranoia, delusions, hallucinations, and impairments in attention and memory [Ref]
Please note that these are most often side effects associated with chronic consumption of a potent CB1 receptor agonist such as THC, and not with a non-psychoactive substance such as CBD.
CB2 Cannabinoid Receptors
CB2 receptors are found mainly in the nervous system and in the immune system. The activation of CB2 receptors has been shown to regulate inflammation, a property that is believed to be responsible for many of the known therapeutic effects of CBD.
CB2 receptors (first discovered in 1993) occur most commonly in the spleen, tonsils, thymus, and immune cells such as mast cells, monocytes, macrophages, B and T cells, and microglia; only a small number exist in the brain.
Changes in CB2 receptor function is synonymous with virtually every type of human disease; be it cardiovascular, gastrointestinal, neurodegenerative, psychiatric, and autoimmune. It even plays a role in liver and kidney function, bone and skin health, cancer, and even pain-related illnesses. [Ref]
Activating the CB2 receptor induces macrophages to destroy the beta-amyloid protein which is the main component of the plaque found in the brains of people with Alzheimer’s disease.
How Do Cannabinoids Work with My Pets Endocannabinoid System?
Cannabinoids are compounds that occur naturally in the cannabis plant. There have been 113 cannabinoids identified in the cannabis plant to date. The two most abundant cannabinoids are THC and CBD. THC is the Cannabinoid that is psychoactive and is responsible for the “high” feeling that marijuana users experience. Cannabidiol (CBD) is a non-psychoactive compound that can relieve pain and reduce inflammation without the psychoactive effects of THC.
Endocannabinoids are molecules that are produced naturally within the body. It is these molecules that bind with the cannabinoid receptors and activate them. The body only creates endocannabinoids and when they are needed.
When introduced into the body, plant cannabinoids such as THC and CBD stimulate the cannabinoid receptors in the same way as the body’s own endocannabinoids do. This in turn triggers some of the same reactions such as reducing inflammation, blocking pain, slowing cell growth and relieving muscle spasms.
The Endocannabinoid System in dogs and all other animals operate in the same way. Introducing external cannabinoids into the system triggers the same therapeutic benefits that the internally produced endocannabinoids would.
Different Functions of the Endocannabinoid System
We still don’t know the full extent of how the Endocannabinoid System works in regulating certain functions of the body. The system has been recognized for playing an important role in modulating the brain, the immune system and the endocrine system.
It’s now believed that the Endocannabinoid system in dogs influences activity in the gastrointestinal tract and affects the areas of the central nervous system that are responsible for appetite. The ECS also appears to play an important role in the regulating hormones that are related to the body’s response to stress and to the reproductive system.
The Endocannabinoid System regulates inflammation. Inflammation is the body’s natural response to damage to tissue or infection but when this response is not controlled properly it can lead to chronic inflammation. This inflammation is believed to be responsible for many chronic diseases. When the endocannabinoid system is stimulated by external cannabinoids it leads to a moderation in the body’s immune response and so reduces inflammation.
Scientist now theorize that the primary function of the endocannabinoid system is to control a vital function of the body that is known as homeostasis, which is the maintenance of the stable internal conditions that all living things need to survive. If that is true, then the Endocannabinoid System plays a huge role in regulating many bodily functions.
The endocannabinoid system is there to respond to stimulation by the body’s own endocannabinoids, but the cannabinoid receptors can also be stimulated by cannabinoids from external sources, including cannabidiol (CBD). Initial research of the benefits of medicinal cannabis was focused on the psychoactive cannabinoid THC which binds to the CBD1 receptors triggering activity. Subsequent research has shown that the non-psychoactive CBD stimulates activity in both CB1 and CB2 receptors by triggering the release of the body’s natural endocannabinoids. This increases the effect throughout the entire body. Research by the National Institutes of Health has shown that CBD can slow the natural breakdown of endocannabinoids which acts to prolong the therapeutic effect.
CBD can also have beneficial effects outside of the endocannabinoid system that would indicate that it could be used to treat a wide range of medical conditions. According to recent studies CBD can inhibit a gene that is known to be responsible for certain types cancers. It has also been discovered that CBD can bind to the receptor that is responsible for controlling pain and inflammation.
Medical research into the effects of CBD is still ongoing, but the list of diseases that it could provide a treatment for is continually growing. As well as being used to treat inflammation, reduce pain and treat gastrointestinal disorders, research is being carried out into the possible use of CBD to treat heart disease, mood disorders, diabetes, asthma, glaucoma, stroke and much more. Some scientists are now even predicting that the use of CBD to simulate the endocannabinoid system in dogs and in humans could revolutionize modern medicine.
And What About our Masters?
Despite a mounting body of evidence on the positive effects and potential applications of CBD, the field of cannabis-related medical research is still new as you would have surmised by now. Mainstream parties are finally accepting that a previously demonised substance actually poses a wide range of therapeutic applications. As such, there are few in vivo studies of CBD on cats; however, there is a wealth of anecdotal and preliminary reports that support its therapeutic action.
Among the conditions CBD can help alleviate in cats are:
- Loss of appetite
- Lack of energy
There are also more serious health conditions where cat owners have reported seeing good results when administering CBD oils. These include common feline diseases such as arthritis, pancreatitis, inflammatory bowel disease, and asthma, which are conditions where inflammation is often the root cause. CBD is largely known for its anti-inflammatory and analgesic properties, helping to fight both the root causes and symptoms of various conditions.
Among people, CBD is used for treating seizures, such as those experienced by patients suffering from a rare form of epilepsy known as Dravet syndrome. There is evidence that CBD is also effective for reducing seizures in cats.
Research and References
Research, notes, references and publications on this topic is expanding daily. We list a few selected sources for your explorations into the realm of the natural
- The Endocannabinoid System (WikiPedia)
- The Endocannabinoid System (Project CBD)
- Beginners Guide to the Endocannabinoid Systems (Leaf Science)
- The Endocannabinoid Systems - An Overview (Medical Marijuana)
- What is the Endocannabinoid Systems and What is Its Role? (Leafly)
- What do dogs, cats and humans have in common with Cannabis? (Healing Without the High)
- The role of the endocannabinoid system in the regulation of endocrine function and in the control of energy balance in humans. (PubMed)
- How Does CBD Affect the Endocannabinoid Systems? (CBD Oil Review)
- Spatial distribution of cannabinoid receptor type 1 (CB1) in normal canine central and peripheral nervous system. (PLoS ONE Open Access Research)
- The use of cannabinoids in animal and therapeutic implications for veterinary medicine: a review (VetMed)
- Is CBD Safe for Dogs? (Journal of the American Medical Association)
- The endocannabinoid system in canine Steroid-Responsive Meningitis-Arteritis and Intraspinal Spirocercosis (PubMed)