The following information was issued in Science and Tech, a market leader in CBD studies.

Receptor Systems in the Brain

The brain contains large numbers of highly specialized cells called neurons. Each neuron connects to many others through structures called synapses. These are sites where one neuron communicates to another by releasing chemical messengers known as neurotransmitters (Figure 1).

A neuron’s sensitivity to a specific neurotransmitter depends on whether or not it contains a receptor that “fits” that transmitter, like an electrical socket fits a plug. If a neuron contains receptors that match a particular neurotransmitter, then it can respond directly to that transmitter. Otherwise, it generally can’t. All neurons contain multiple neurotransmitter receptors, allowing them to respond to some neurotransmitters but not others.

Brain receptors are not only sensitive to neurotransmitters produced naturally within the brain, like dopamine or serotonin, but also chemical messengers produced outside the body, such as plant cannabinoids like THC or CBD. So when you ingest an edible or inhale some vapor, you’re allowing compounds originally produced by a plant to enter your body, travel through your bloodstream, and enter your brain. Once they arrive, these plant-derived compounds can influence brain activity by interacting with receptors on neurons. But they don’t interact with all neurons, just the ones that have the appropriate receptors.

CBD Influences Many Different Receptor Systems

Although it is a cannabinoid, CBD does not directly interact with the two classical cannabinoid receptors (CB1 and CB2).  Instead, it affects signaling through CB1 and CB2 receptors indirectly. This partly explains why, in contrast to THC, CBD is non-intoxicating. In addition to its indirect influence on the CB1 and CB2 receptors, CBD can increase levels of the body’s own naturally-produced cannabinoids (known as endocannabinoids) by inhibiting the enzymes that break them down.

Even more intriguing: CBD also influences many non-cannabinoid receptor systems in the brain, interacting with receptors sensitive to a variety of drugs and neurotransmitters (Figure 2). These include opioid receptors, known for their role in pain regulation. Opioid receptors are the key targets of pharmaceutical pain killers and drugs of abuse such as morphine, heroin, and fentanyl. CBD can also interact with dopamine receptors, which play a crucial role in regulating many aspects of behavior and cognition, including motivation and reward-seeking behavior.

References
Blessing EM, Steenkamp MM, Manzanares J, Marmar CR. Cannabidiol as a Potential Treatment for Anxiety Disorders. Neurotherapeutics. 2015;12(4):825-36. [PDF]
Mechoulam R, Parker LA. The Endocannabinoid System and the Brain. Annu Rev Psychology. 2013;64:21-47. [PDF]
Morgan CJ, Schafer G, Freeman TP, Curran HV. Impact of cannabidiol on the acute memory and psychotomimetic effects of smoked cannabis: naturalistic study: naturalistic study. Br J Psychiatry. 2010;197(4):285-90. [PDF]
Parsons LH, Hurd YL. Endocannabinoid signalling in reward and addiction. Nat Rev Neurosci. 2015;16(10):579-94. PDF
Zlebnik NE, Cheer JF. Beyond the CB1 Receptor: Is Cannabidiol the Answer for Disorders of Motivation?. Annu Rev Neurosci. 2016;39:1-17. PDF

 

NICK JIKOMES