The influence of cannabinoids on generic traits of neurodegeneration

In an increasingly ageing population, the incidence of neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease are rising. While the aetiologies of these disorders are different, a number of common mechanisms that underlie their neurodegenerative components have been elucidated; namely neuroinflammation, excitotoxicity, mitochondrial dysfunction and reduced trophic support. Current therapies focus on treatment of the symptoms and attempt to delay the progression of these diseases but there is currently no cure. Modulation of the endogenous cannabinoid system is emerging as a potentially viable option in the treatment of neurodegeneration. Endocannabinoid signalling has been found to be altered in many neurodegenerative disorders. To this end, pharmacological manipulation of the endogenous cannabinoid system, as well as application of phytocannabinoids and synthetic cannabinoids have been investigated. Signalling from the CB1 and CB2 receptors are known to be involved in the regulation of Ca2+ homeostasis, mitochondrial function, trophic support and inflammatory status, respectively, while other receptors gated by cannabinoids such as PPARγ, are gaining interest in their anti-inflammatory properties. Through multiple lines of evidence, this evolutionarily conserved neurosignalling system has shown neuroprotective capabilities and is therefore a potential target for neurodegenerative disorders. This review details the mechanisms of neurodegeneration and highlights the beneficial effects of cannabinoid treatment.