Does your endocannabinoid system impact social behavior? A recent study from the University California-Irvine examines how the ECS may interact with the hormone oxytocin to positively impact the rewards associated with social interaction.
What is Oxytocin?
For today’s Science 101 lesson, let’s have a brief refresher on what exactly oxytocin is. Mammals make a key neuro-hormone called oxytocin that’s produced in the hypothalamus and stored in the pituitary gland of the brain/central nervous system.
Oxytocin plays a role in intimacy, sexual reproduction, childbirth, and the socially rewarding effects of hugging, trust related behaviors, pleasant touch, emotions of love, and social interaction. In fact, a study published in 2012 out of Singapore demonstrated that individuals with more extreme levels of oxytocin in the blood were likely to be more trusting than those with lower levels.
The Endocannabinoid System and Its Physiological Impact
One of the most common experiences described by cannabis users include enhanced social interactions, interpersonal communication, and social bonding. This clear overlap in cannabis consumption and pro-social behavior has led scientists to begin exploring the potential link between endocannabinoid signaling and oxytocin.
To briefly review, the endocannabinoid system is a group of specialized fatty acid-based signaling chemicals (think “keys”), their receptors (think “locks”), and the metabolic enzymes that produce and break them down. These endocannabinoid chemical signals act on similar brain cell receptors as the active compounds found in cannabis – cannabidiol (CBD), and Δ9-tetrahydrocannabinol (THC). Don’t confuse endocannabinoids with phytocannabinoids – the latter, of which well over 90 have been found to exist, are chemical plant derivatives (found mostly within cannabis species) such as CBD and THC that interact with the endocannabinoid system of hormones, receptors, and enzymes. Endocannabinoids are known to influence a variety of physiological systems, including appetite, pain/sensation and inflammation, body temperature regulation, intra-ocular pressure, muscle control, energy balance, metabolism, sleep health, stress responses, motivation/reward, memory, and mood, the latter of which brings us to the UC-Irvine study. What link exists, if any, between the ECS and social behaviors?
The Relationship Between the ECS and Sociability
According to UC-Irvine’s recent pre-clinical research study, there is a strong link between the “love” and “trust” hormone oxytocin and the naturally occurring endocannabinoid “bliss” and “delight” molecule known as anandamide. This is the first study of its kind to show a direct link in the brain of mice between these systems.
The animal study set out to measure levels of anandamide in the brain of mice that had either been allowed normal social interaction with other mice or kept in isolation. Researchers found that in mice with social interaction, the levels of anandamide increased in an area of the brain that’s critical for motivation, pleasure, and reward. When the mice were given drugs that enhanced anandamide signaling, their pleasure associated with socialization increased. However, when the cannabinoid receptors were blocked, the mice were prevented from experiencing the rewards of social interactions. This part of the experiment confirmed the importance of anandamide and the endocannabinoid system to social behaviors.
The second part of the study reinforced oxytocin’s role in social bonding and the pleasure derived from social interactions in the same mice when they stimulated oxytocin-releasing brain cells. Researchers found that oxytocin also enhanced the mobilization and production of anandamide within the same area of the brain responsible for motivation and reward.
Not surprisingly, when oxytocin receptors were blocked, it also stopped the normal pleasure and reward sensation obtained by social interactions. Amazingly, when anandamide was prevented from being degraded in this area of the brain, it completely offset the loss of social reward and pleasure observed when blocking the oxytocin receptor.
So what does this all mean? The study and data indicate that social reward and the effects of the “love, trust, and social hormone” oxytocin is driven by anandamide and the endocannabinoid system as an underlying keystone to optimizing social behavior. It’s an exciting revelation, as the underlying dependence of social reward on the endocannabinoid system provides a potential therapeutic strategy in the future to help individuals with social dysfunction, anxiety disorders, pervasive developmental, and autism spectrum disorders.
Zhong S, Monakhov M, Mok HP, et al. U-Shaped Relation between Plasma Oxytocin Levels and Behavior in the Trust Game. Slattery DA, ed. PLoS ONE. 2012;7(12):e51095.
Don Wei, DaYeon Lee, Conor D. Cox, Carley A. Karsten, Olga Peñagarikano, Daniel H. Geschwind, Christine M. Gall, and Daniele Piomelli Endocannabinoid signaling mediates oxytocin-driven social reward PNAS 2015;112 (45):14084-14089.