Cannabinoid anticonvulsant effects partly work through ATP-sensitive potassium channels | Research

The takeaway

In mice, a cannabinoid receptor agonist raised seizure thresholds through CB1 receptor activation and ATP-sensitive potassium channel opening, with the mechanism involving reduced mitochondrial ATP levels in the hippocampus.

People interested in epilepsy mechanisms, cannabinoid pharmacology, and the science behind cannabis anti-seizure effects.

CB1 agonist + potassium channel opener synergized to produce anticonvulsant effects at subeffective doses

What the researchers found

WIN 55,212-2 at 10 mg/kg significantly increased clonic seizure threshold via CB1 (blocked by AM-251) but not CB2 (AM-630 had no effect). The potassium channel blocker glibenclamide reversed the anticonvulsant effect. The potassium channel opener cromakalim enhanced the effect of a subeffective WIN dose. CB1 agonism decreased hippocampal ATP levels.

Why it matters

Understanding the precise mechanism of cannabinoid anticonvulsant effects is crucial for developing better epilepsy drugs. This study adds a new piece: the CB1-ATP-potassium channel pathway provides a specific molecular target that could be independently optimized.

The numbers in context

WIN 55,212-2 at 10 mg/kg increased seizure threshold (p<0.001). Effect blocked by CB1 antagonist AM-251 (p<0.001) but not CB2 antagonist AM-630. Glibenclamide (1 mg/kg) reversed the effect (p<0.001). Cromakalim (10 mcg/kg) + subeffective WIN dose (3 mg/kg) = significant anticonvulsant effect.

How the study worked

Male NMRI mice treated with combinations of cannabinoid receptor agonist/antagonists and potassium channel openers/blockers, with clonic seizure threshold as the primary outcome and hippocampal ATP measurement to clarify the mechanism.

What this study cannot tell us

Mouse model using pharmacologically induced seizures, not a chronic epilepsy model. WIN 55,212-2 is a synthetic cannabinoid, not THC or CBD. Single acute dose study. ATP measurement at one brain region only.

How to read the evidence

Preliminary: well-controlled animal pharmacology study with clear mechanistic findings, but mouse model only.

When this study was published

Published in 2019.

The bigger picture

This adds potassium channels to the growing list of mechanisms through which cannabinoids fight seizures (alongside GPR55, TRPV1, and adenosine reuptake). Multiple pathways may explain why CBD and THC have anticonvulsant properties that single-mechanism drugs don't replicate.

Questions still open

Does CBD work through the same ATP-potassium channel mechanism? Could combining cannabinoids with potassium channel openers improve epilepsy treatment? Is the ATP reduction a beneficial mechanism or a potential concern for chronic use?

Common questions

How do cannabinoids prevent seizures?

This study identified one mechanism: CB1 receptor activation reduces ATP levels in the hippocampus, which opens ATP-sensitive potassium channels. This hyperpolarizes neurons, making them less excitable and raising the threshold for seizure onset.

Could this lead to better epilepsy drugs?

Understanding the specific pathways allows researchers to design drugs targeting the beneficial mechanism (potassium channel opening) while potentially avoiding side effects from other cannabinoid actions.

Read the original research

Activation of ATP-sensitive K-channel promotes the anticonvulsant properties of cannabinoid receptor agonist through mitochondrial ATP level reduction.

Epilepsy & behavior : E&B, 93, 1-6

View on PubMed ↗Publisher’s paper ↗

Citation

Haj-Mirzaian, Arvin; Ramezanzadeh, Kiana; Afshari, Khashayar; Mousapour, Pouria; Abbasi, Nooshin; Haj-Mirzaian, Arya; Nikbakhsh, Rajan; Haddadi, Nazgol-Sadat; Dehpour, Ahmad Reza. (2019). Activation of ATP-sensitive K-channel promotes the anticonvulsant properties of cannabinoid receptor agonist through mitochondrial ATP level reduction.. Epilepsy & behavior : E&B, 93, 1-6. https://doi.org/10.1016/j.yebeh.2019.01.025