Now, experiments by Oliver Ullrich and colleagues have pinpointed how one of the brain's endocannabinoids protects neurons from inflammation after such damage. They say their studies could lead to new drugs to treat the inflammation and brain degeneration from MS or other such disorders.
In an article in the January 5, 2006, issue of Neuron, the researchers reported experiments showing how the endocannabinoid anandamide (AEA) protects brain cells from inflammation. Such a role in the brain's immune system is distinct from cannabinoids' effects on neuronal signaling that produce the behavioral effects of marijuana.
When Ullrich and colleagues analyzed brain tissue from people with MS, they found elevated levels of AEA, compared to healthy tissue. And in studies with mouse brain slices, they found that inducing damage with a brain-cell-exciting chemical, called NMDA, caused an invasion of the brain's immune cells, called microglia, and an increase in AEA levels.
Importantly, they found that adding AEA to such damaged brain tissue abolished inflammatory damage to the brain cells, but did not reduce the primary "excitotoxic" damage from the chemical. They found similar effects of AEA when they damaged the brain tissue by depriving it of oxygen and glucose.
The researchers also found that when they used a drug to block the receptors on microglial cells by which AEA effects the cells, inflammatory damage was increased.
The researchers also explored the mechanism by which AEA prevents inflammatory damage. They found th