A new study in the journal Neuron has identified a previously unknown way that cannabidiol (CBD) – a substance found in cannabis – reduces seizures in people with epilepsy.
Scientists already knew that CBD blocks the ability of a molecule, called lysophosphatidylinositol (LPI), to amplify nerve signals in the hippocampus. Too much of this signal amplification promotes seizures.
But the exact mechanism was poorly understood. The new study suggests it blocks a “positive feedback loop” in the brain.
While LPI causes nerve signal amplification it also weakens signals that counter seizures, which likely encourages more seizures, which then increases levels of LPI and the protein it binds to (GPR55), and the cycle continues.
“Our results deepen the field’s understanding of a central seizure-inducing mechanism, with many implications for the pursuit of new treatment approaches,” says Richard W. Tsien, chair of the Department of Physiology and Neuroscience at New York University in the US, and corresponding author of the new study.
“The study also clarified, not just how CBD counters seizures, but more broadly how circuits are balanced in the brain,” adds Tsien.
“Related imbalances are present in autism and schizophrenia, so the paper may have a broader impact.”
CBD disrupts a seizure-inducing positive feedback loop
In the brain, neurons…
