Cannabinoid Exposure Linked to Central-Amygdala Stress Neurons in Mice

Dose linked to SOM-neuron activity

According to the report, mice given the synthetic cannabinoid CP 55,940 froze more and spent less time near a synthetic predator odor than placebo-treated mice.

Implanted microscopes showed greater activity in central-amygdala somatostatin (SOM) neurons at higher cannabinoid doses. In a separate experiment, suppressing synaptic output from those neurons in genetically engineered mice reduced, but did not eliminate, avoidance of the odor.

Cannabinoids were known to affect the central amygdala, but how they interacted with its somatostatin neurons in threat-related responses remained unclear.

The reported mouse experiments connected cannabinoid exposure with dose-linked activation of central-amygdala somatostatin neurons and stronger anxiety-like defensive responses under predator-odor stress. Inhibiting those neurons' synaptic output partially reduced avoidance.

A mouse circuit is not yet a human mechanism

The findings point to a specific brain-cell circuit that may help account for anxiety-like responses to cannabinoids under stress. They do not establish the same mechanism in people, nor do they demonstrate a treatment.