The Endocannabinoid System (ECS)

Cannabinoids are compounds found in cannabis plants, but did you know they are also found in most animal organisms too? We even make our own cannabinoids and we have millions of cannabinoid receptors in our body to make sure these compounds can keep our body and mind working well. This mix of cannabinoids, receptors and enzymes is called our Endocannabinoid System (ECS).

Our ECS helps to regulate and moderate transmission between nerve cells. It helps the nerves all over our body communicate with eachother. We call this a neurotransmitter system. There are several neurotransmitter systems in the body (e.g. dopamine system) and the ECS is one of them.

The cannabinoids found in plants are called Phytocannabinoids, and they interact with our ECS. Here's how...

Our nervous system is made up of our brain, spinal chord and billions of nerves. This nervous system is the control centre of our body. It controls how we think, feel, move, breathe and how all other systems in our body work. It is really important that all of our nerves communicate with each other well. This is how we regulate our body.

Different nerve cells need to talk to each other, so that they can pass on signals that make things happen or change in the body. Nerve cells are called Neurons and they don't touch each other. They send messages across a gap between them. This gap is called a synaptic cleft.

Messages are sent via neurotransmitters - these are chemicals that cross the synaptic cleft from one neuron to another - carrying the message across.

We have different neurotransmitter systems for different roles in our body. We have a noradrenaline system, a histamine system or a dopamine system - these are some of many. The ECS helps to ensure homeostasis and seems to have a controlling effect over other systems in the body too. We call this a neuromodulatory system - this means that it adjusts the way cells communicate between neurons.

Endogenous Cannabinoids (Endocannabinoids for short) are cannabinoids that we make in our own body. They are lipids that bind to cannabinoid receptors.

The first endocannabinoids to be discovered - and the best known, are called Anandamide and 2-AG.

Unlike other neurotransmitters which are made and stored ahead of time, Anandamide and 2-AG are released on demand.

When released Anandamide and 2-AG bind to receptors called CB1 and CB2. Anandamide triggers a partial effect at these sites, where as 2-AG interacts more fully at these receptor sites.

When these endocannabinoids bind to CB1 and CB2 they regulate the transmission of messages at these sites.

Receptors are found on the end of nerves. CB1 receptors are found in very high numbers in the central nervous system and are associated with psychoactive and neuromodulatory effects. CB2 is found in less abundance in the central nervous system and is found in the immune system and is associated with anti-inflammatory and immunomodulatory effects.

The ECS also needs enzymes to break down the endocannabinoids when they have finished doing their jobs. The two main enzymes involved in deactivating endocannabinoids are Fatty acid amide hydrolase (FAAH) and Monoacylglycerol acid lipase (MAGL).

So how does it all work together...?

The ECS is not the same as other neurotransmitter systems. In fact, it almost works in reverse.

In all other neurotransmitter systems, when a nerve impulse arrives at the pre-sympatic neuron (the one sending the message), chemical neurotransmitters are released and travel across the synaptic cleft and bind to the receptors of the post-synaptic neuron (the one receiving the message). The message then travels along the nerve so that a response can happen.

This process does need to be switched off though, so that impulses don't fire off continuously. This is where the ECS finds it's main role.

Once the above process has been completed, Anandamide and 2-AG are released. However they travel backwards towards the pre-synaptic neuron. They bind to the receptors CB1 and CB2 and switch off or modulate the original transmission. It's like they balance the messages that are being sent all around the body. I like to think of them as endocannabinoid Marshalls - keeping things balanced and in order.

The ECS does this all throughout the body. The effect it has depends on the site of the receptors. If they are in the spinal chord for example then the ECS may regulate pain. If the receptors are in the immune system they may regulate inflammatory responses.

Phytocannabinoids (the ones in plants) will also bind to CB1 and CB2 receptors. THC and CBD are the main examples of this. When we introduce them into the body they also act on the ECS. This is why medical cannabis has so many benefits - because the neurotransmitter system that it works on is found throughout so many body systems.