“Cannabinoids (CBs) from the Cannabis sativa L. plant, including tetrahydrocannabinol, the principal psychoactive component of marijuana, produce euphoria and relaxation and also impair motor coordination, perception of time, and short-term memory. The principal actions of CBs are mediated by activation of their cognate receptors on presynaptic nerve ends. Various types of cannabinoid receptors, including the orphan G-protein coupled receptors CB1 and CB2, are found in blood vessels, the central nervous system, and immune cells. While CB1 is expressed abundantly in several areas in the brain as well as in peripheral tissues, CB2 is primarily expressed in the immune system, although it was recently detected at low levels in peripheral nerve endings, microglial cells, and astrocytes, as well as in the cerebellum and brain stem. CB1 receptor activation is involved in the control of neural cell fate and mediates neuroprotectivity in different in vivo models of brain injury, including excitotoxicity and ischemia.
In recent years, the capacity of CBs to effect neuroprotection and neurotoxicity has received increasing attention. Evidence of possible neuroprotective effects has accumulated in vitro from models of neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases and multiple sclerosis, as well as from in vivo clinical trial data. These compounds are also able to decrease inflammation by acting on glial cells that influence neuronal survival. The molecular mechanisms underlying cannabinoid-mediated neuroprotection are still poorly understood, but may include the direct activation of neuronal survival signaling pathways through cannabinoid receptors or indirect effects mediated by microglial CB2-receptor stimulation.
Here, we investigated the neuroprotective function of a synthetic cannabinoid-receptor agonist (WIN55.212.2)… These results indicate that WIN55.212.2 may be a candidate for treatment of neurodegenerative diseases, including Parkinson’s disease.”
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145842/