February 2010: The beneficial effects of cannabinoids in one portion of the brain is fully understood (Goethe Universität Frankfurt am Main; Germany)

First some background: The portion of the brain used in this experiment is called the dentate gyrus. The dentate gyrus is part of the temporal lobe of the cortex, which, in layman’s terms, is the portion of the brain that exists directly on both sides of the head. The temporal lobe is involved in the processing of sounds, as well as the semantics of vision and the formation of memories. Additionally, cell damage and death in the dentate gyrus is known to be one of the etiological causes of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. It has also been well documented that cannabinoids reduce inflammation and have a protective effect in the dentate gyrus.

The new information: Although the end biological effect of cannabinoids in this area of the brain has been known for some time, the molecular events have now been determined. The experiment examined the effects of cannabinoid receptor-mediated activation of ion channels in the brain cells at varying concentrations of cannabinoids. It was found that at lower concentrations (0.01 muM), the cannabinoid most effectively mediated neuroprotection and anti-inflammatory effects, and with higher doses, the cannabinoids were less effective. It was also shown through channel blocking and activation that cannabinoids led to the inhibition of TRPV1 channels, which allow passage of calcium, magnesium, and sodium, as well as the activation of Ca(v)2.2, a voltage-gated N-type calcium channel.

What this means: This study allowed a look at the dosage-dependent effects of cannabinoids. As more is learned about how the concentration of cannabinoids affects their benefits, it will be possible to determine more effective dosages of cannabis itself. Additionally, by elucidating the molecular mechanisms of neuroprotection and anti-inflammation, it could be possible to accentuate these specific actions of cannabinoids by the use of drugs that affect the ion channels whose permeability was shown to be altered. This could lead to more effective treatment of neurodegenerative diseases such as Alzheimer’s of Parkinson’s.

Kock, M., et al. “The cannabinoid WIN 55,212-2-mediated protection of dentate gyrus granule cells is driven by CB(1) receptors and modulated by TRPA1 and Ca(v)2.2 channels.” Hippocampus. (2010): preprint.