In a previous blog entry, Overview of How the Endocannabinoid System Works, we described how our Endocannabinoid Systems (ECSs) contain three basic sets of components: 

• Cannabinoid receptors: Receptors on cell membranes that are activated by cannabinoids
• Cannabinoids: The messengers, or neurotransmitters, that activate cannabinoid receptors
• Cannabinoid enzymes: The enzymes that break down, or inactivate, cannabinoids

Each type of cell has a particular speed at which new cell receptors are naturally synthesized and then subsequently degraded. However, activation of cell receptors by messengers causes receptors to degrade more quickly.^[1]

The number of receptors present on the cell at any given time thus depends on how quickly new receptors are being synthesized, relative to how quickly existing receptors are degrading. If receptors are degrading faster than they’re being synthesized, then the total number of receptors on the cell will decrease, or experience downregulation. Conversely, if receptors are being synthesized faster than they’re degrading, the total number of receptors on the cell will increase, or experience upregulation (see Figure 1).