Bioethics Blogs

Anxiety Reduction: Exploring the Role of Cannabinoid Receptors

Green and blue swirls

Caption: Cannabinoid receptor 1 (green) in the mouse brain. All cell nuclei appear blue.
Credit: Margaret Davis, National Institute on Alcohol Abuse and Alcoholism, NIH

Relief of anxiety and stress is one of the most common reasons that people give for using marijuana [1]. But the scientific evidence is rather sparse about whether there’s a biological explanation for that effect.

More than a decade ago, researchers set out to explore the link between marijuana and anxiety reduction, but the results of their experiments were inconclusive [2]. Recently, a team led by NIH-funded researchers at Vanderbilt University Medical Center in Nashville decided to tackle the question again, this time using more sensitive tools that have just become available in recent years.

In humans, mice, and other mammals, the body makes natural chemicals, called endocannabinoids, that interact with certain proteins, called type 1 cannabinoid receptors (CB1), that are located on the surface of nerve cells. We know that the endocannabinoid system is critical for normal brain development and activity, immunity, and the physiological regulation of stress responses. We also know that CB1 receptors interact with the primary cannabinoid in marijuana, a mind-altering chemical known as delta-9-tetrahydrocannabinol (THC).

To investigate whether there’s a biological basis for the anxiety-relieving effects associated with marijuana use, the Vanderbilt-led team decided to conduct a mouse study to search for CB1 receptors in the central amygdala—a region of the brain that, among other things, controls anxiety and response to stress. And, in a paper published in the journal Neuron, the researchers reported they did indeed detect CB1 receptors in the central amygdala of the mouse brain.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.