Researchers in Germany, who are set to begin human trials later this year, cured elderly mice of memory loss with cannabis – and say the drug may even help delay Alzheimer’s disease.
The mental power of older mice improved dramatically after they were given THC, and brain connections in the hippocampus – which controls learning, memory and emotions – were firing as well as those of young adults. It’s hoped the same may apply to humans, with trials expected to begin this year. The trials will use purified THC so the dosage can be precisely controlled.
THC treatment for 28 days restored the learning and memory performance of mature and old animals in the water maze, novel object location recognition and social recognition tests to the levels observed in young mice.’
Low-dose treatment with THC or cannabis extracts could be a potential strategy to slow down or even reverse cognitive decline in the elderly, reported Professor Andreas Zimmer of the Institute of Molecular Psychiatry at Bonn University.
This treatment success is the result of years of meticulous research. First of all, the scientists discovered that the brain ages much faster when mice do not possess any functional receptors for THC. These cannabinoid 1 (CB1) receptors are proteins to which the substances dock and thus trigger a signal chain. CB1 is also the reason for the intoxicating effect of THC in cannabis products, which accumulate at the receptor.
THC imitates the effect of cannabinoids produced naturally in the body, which fulfil important functions in the brain. “With increasing age, the quantity of the cannabinoids naturally formed in the brain reduces,” says Prof. Zimmer. “When the activity of the cannabinoid system declines, we find rapid ageing in the brain.”
“We repeated these experiments many times,” says team leader Andreas Zimmer. “It’s a very robust and profound effect.”
THC seemed to have the opposite effect in young mice: when they were given THC, their performance in some tasks declined.
The North Rhine-Westphalia science minister Svenja Schulze commented: “Although there is a long path from mice to humans, I feel extremely positive about the prospect that THC could be used to treat dementia.”
The results were published in the journal Nature Medicine.