New Tools Are Revealing How the Endocannabinoid System Works in Real Time in Living Brains

New biosensors and imaging tools can now track endocannabinoid signaling at individual synapses in behaving animals. In the hippocampus, endocannabinoid-mediated inhibition by CCK-positive interneurons plays a key role in shaping place cell properties, the neurons that encode spatial location.

This is a comprehensive review synthesizing recent advances in endocannabinoid imaging, biosensors, and in vivo recording technologies. The authors focus on hippocampal circuits as a model system, examining how new tools have overcome the historical limitation that endocannabinoid lipid signals are too short-lived to study in living tissue.

For decades, understanding of the endocannabinoid system was limited to lab-dish experiments because the signals degrade too quickly to track in living brains. These new technologies are fundamentally changing what researchers can learn about how cannabis and the natural endocannabinoid system affect brain circuits in real time.

Understanding endocannabinoid signaling at the synapse level in living animals could transform the fields of cannabis neuroscience and cannabinoid medicine. If researchers can see exactly which synapses are affected and when, it opens the door to much more targeted interventions.

As a review, this synthesizes existing work rather than presenting new data. Most of the highlighted advances focus on hippocampal circuits, and it remains to be seen how well the findings generalize to other brain regions.