Cannabidiol (CBD) reduced seizure severity and improved recognition memory in rats with epilepsy-like symptoms, according to a study published in Neuropharmacology.
Researchers from Minzu University of China and Shahid Beheshti University of Medical Sciences examined the role of hyperpolarization-activated cyclic nucleotide-gated channel-1 (HCN1), a protein involved in regulating neuronal activity and excitability in the brain.
The researchers used electrical stimulation to induce progressively worsening seizures in rats, a process known as kindling. Some animals also underwent HCN1 knockdown, which reduced expression of the channel in the dentate gyrus, a region of the hippocampus involved in memory and seizure activity.
Reducing HCN1 expression accelerated seizure progression, prolonged abnormal electrical activity and increased seizure-related spikes. It also impaired synaptic transmission, long-term potentiation and the rats’ ability to recognize previously encountered objects.
CBD was administered directly into the brain every other day at a dose of 100 nanograms. The treatment significantly reduced seizure severity and improved several measures of brain function, including synaptic plasticity and recognition memory.
However, CBD’s protective effects were partially weakened in rats with reduced HCN1 expression. Researchers said this suggests the channel plays a role in CBD’s anticonvulsant and neuroprotective actions, although CBD also appeared to work through mechanisms independent of HCN1.
The findings identify HCN1 as a potential mediator of seizure progression and hippocampal dysfunction. They also provide additional evidence that CBD may protect against both seizures and some of the cognitive problems associated with epilepsy.
Because the study was conducted in rats and involved direct administration of CBD into the brain, further research is needed to determine how the findings may translate to people.
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