The easiest way to think of cannabinoid receptors is as an antenna, just like the one you would find on a television or car. An antenna in your vehicle receives signals from some external source, transmitting this information to your receiver, who in turn picks up the signal and passes it on to your stereo system. But, instead of looking at the directional directions of each antenna, each is assigned a different frequency to receive the signal. When all the antennas receive the same wave, they can produce a stereo effect, broadcasting the sound and music to the listeners.
Cannabinoid receptors, found naturally in the human body, are found in the endocannabinoids or lipids at the end of their cell membrane. These Cannabinoid Receptors (ECR) directly interact with the neurotransmitters that act as messengers to regulate mood, appetite, sleep, sexual behavior, blood pressure and temperature. There are two types of Cannabinoid Receptors: Terpenes and CB2 Receptors. Both types have different binding sites, which help them to distinguish one another when the signal arrives. So, when the signal does not arrive at the same place twice, they do not interact, sending conflicting signals that result in a variety of behaviours and conditions.
Terpinen-4-ol and N-methyl-o-acyl-glucosamine (NMG, GABA), two natural neurotransmitters that maintain homeostasis in the brain and spinal cord, are thought to work by interacting through Cannabinoid Receptors to modulate appetites. They appear to bind to fatty acids in the membranes of neurons in order to inhibit synaptic firing, which in effect regulates neuronal firing. Cannabinoid receptors have been found to be expressed in the central nervous system, brain, pancreas and liver; as well as in the placenta and aorta. Therefore, it appears that Cannabinoid Receptors play a critical role in maintaining homeostatic balance in nature.
Besides acting on Cannabinoid Receptors, endocannabinoids may also bind to other neurotransmitter systems including Serotonin and glutamate. Endocannabinoids are thought to function through inhibition of GABA neurotransmission, which has been implicated in the management of anxiety, depression, seizures and chronic pain. Other studies have shown that endocannabinoid molecules may also bind to 5-HT receptor coupled glomeruli, which may mediate the effects of Cannabinoid Receptors in the brain.
There is much less evidence on the precise molecular mechanisms by which Cannabinoid Receptors impact on bodily functions. However, it is clear that Cannabinoid Receptors increase blood flow in the brain, which may mediate its positive effects on mood and anxiety. Similarly, Cannabinoid Receptors increase blood pressure and reduce heart rate in people suffering from hypertension.
Endocannabinoids also modulate gastrointestinal tract functioning and reduce nausea and vomiting in certain diseases. Furthermore, endocannabinoid concentrations and receptor occupancy at synapse sites in the brain has been found to correlate with emotional states, which may explain some of the addictive characteristics exhibited by many recreational users of Cannabinoid Receptors.