Parkinson's Disease is a degenerative disorder of the nervous system marked by accelerated degeneration of dopamine-producing neurons in the Substantia Nigra in the brain.
Typical symptoms of Parkinson's Disease , such as (intentional) tremor, rigidity and slowness of movement are mostly ascribed to degenerating Substantia Nigra neurons.
As the disease progresses other neurons, such as those in the cerebral cortex also start to degenerate. At this stage, secondary symptoms such as dementia and depression become prominent.
In Parkinson’s patients, microglia surrounding lesions in the substantia nigra have increased CB2 levels (Gómez-Gálvez et al., 2015). Experiments in mice showed that this increase in CB2 is neuroprotective. Thus CB2 signalling may provide a therapeutic avenue to prevent neurodegeneration in Parkinson’s.
GPR6 has been associated with Parkinson's disease (Laun & Song, 2017).
In a marmoset model of Parkinson’s THC improved locomotor activity (van Vliet et al., 2006).
Similarly, systemic application of OEA, and to a lesser extent PEA, was found to inhibit pro-inflammatory cytokines and thus to protect against neurodegeneration (Sayd et al., 2014).
Carroll, C.B., Zeissler, M.-L., Hanemann, C.O., and Zajicek, J.P. (2012). Δ9-tetrahydrocannabinol (Δ9-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson’s disease. Neuropathol. Appl. Neurobiol. 38, 535–547.
García, C., Palomo-Garo, C., García-Arencibia, M., Ramos, J., Pertwee, R., and Fernández-Ruiz, J. (2011). Symptom-relieving and neuroprotective effects of the phytocannabinoid Δ9-THCV in animal models of Parkinson’s disease. Br. J. Pharmacol. 163, 1495–1506.
Gómez-Gálvez, Y., Palomo-Garo, C., Fernández-Ruiz, J., and García, C. (2015). Potential of the cannabinoid CB2 receptor as a pharmacological target against inflammation in Parkinson’s disease. Prog. Neuropsychopharmacol. Biol. Psychiatry.
González-Aparicio, R., and Moratalla, R. (2014). Oleoylethanolamide reduces L-DOPA-induced dyskinesia via TRPV1 receptor in a mouse model of Parkinson´s disease. Neurobiol. Dis. 62, 416–425.
Gonzalez-Aparicio, R., Blanco, E., Serrano, A., Pavon, F.J., Parsons, L.H., Maldonado, R., Robledo, P., Fernandez-Espejo, E., and de Fonseca, F.R. (2014). The systemic administration of oleoylethanolamide exerts neuroprotection of the nigrostriatal system in experimental Parkinsonism. Int. J. Neuropsychopharmacol. Off. Sci. J. Coll. Int. Neuropsychopharmacol. CINP 17, 455–468.
de Lago, E., de Miguel, R., Lastres-Becker, I., Ramos, J.A., and Fernández-Ruiz, J. (2004). Involvement of vanilloid-like receptors in the effects of Anandamide on motor behavior and nigrostriatal dopaminergic activity: in vivo and in vitro evidence. Brain Res. 1007, 152–159.
Lastres-Becker, I., Molina-Holgado, F., Ramos, J.A., Mechoulam, R., and Fernández-Ruiz, J. (2005). cannabinoids provide neuroprotection against 6-hydroxydopamine toxicity in vivo and in vitro: relevance to Parkinson’s disease. Neurobiol. Dis. 19, 96–107.
Laun, A. S., & Song, Z.-H. (2017). GPR3 and GPR6, novel molecular targets for cannabidiol. Biochemical and Biophysical Research Communications, 490(1), 17-21. https://doi.org/10.1016/j.bbrc.2017.05.165
Moldzio, R., Pacher, T., Krewenka, C., Kranner, B., Novak, J., Duvigneau, J.C., and Rausch, W.-D. (2012). Effects of cannabinoids Δ(9)-tetrahydrocannabinol, Δ(9)-tetrahydrocannabinolic acid and cannabidiol in MPP+ affected murine mesencephalic cultures. Phytomedicine Int. J. Phytother. Phytopharm. 19, 819–824.
Mounsey, R.B., Mustafa, S., Robinson, L., Ross, R.A., Riedel, G., Pertwee, R.G., and Teismann, P. (2015). Increasing levels of the endocannabinoid 2-AG is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson’s disease. Exp. Neurol.
Sayd, A., Antón, M., Alén, F., Caso, J.R., Pavón, J., Leza, J.C., Rodríguez de Fonseca, F., García-Bueno, B., and Orio, L. (2014). Systemic administration of oleoylethanolamide protects from neuroinflammation and anhedonia induced by LPS in rats. Int. J. Neuropsychopharmacol. Off. Sci. J. Coll. Int. Neuropsychopharmacol. CINP 18.
van Vliet, S.A.M., Vanwersch, R.A.P., Jongsma, M.J., van der Gugten, J., Olivier, B., and Philippens, I.H.C.H.M. (2006). Neuroprotective effects of modafinil in a marmoset Parkinson model: behavioral and neurochemical aspects. Behav. Pharmacol. 17, 453–462.
In a 22-patient trial, smoking 0.5g cannabis significantly improved tremor and bradykinesia (slow movement) within 30 minutes of consumption (Lotan et al., 2014).
In a patient survey, 25% of Parkinson’s patients reported smoking cannabis for symptom relief. Of these, almost 50% reported moderate to substantial relief of symptoms (Venderová et al., 2004). In a small-scale trial, CBD was found to decrease psychotic symptoms of Parkinson’s without affecting motor function (Zuardi et al., 2009). In a 4-patient study,
Chagas, M.H.N., Eckeli, A.L., Zuardi, A.W., Pena-Pereira, M.A., Sobreira-Neto, M.A., Sobreira, E.T., Camilo, M.R., Bergamaschi, M.M., Schenck, C.H., Hallak, J.E.C., et al. (2014). Cannabidiol can improve complex sleep-related behaviours associated with rapid eye movement sleep behaviour disorder in Parkinson’s disease patients: a case series. J. Clin. Pharm. Ther. 39, 564–566.
Lotan, I., Treves, T.A., Roditi, Y., and Djaldetti, R. (2014). Cannabis (medical marijuana) treatment for motor and non-motor symptoms of Parkinson disease: an open-label observational study. Clin. Neuropharmacol. 37, 41–44.
Venderová, K., Růzicka, E., Vorísek, V., and Visnovský, P. (2004). Survey on cannabis use in Parkinson’s disease: subjective improvement of motor symptoms. Mov. Disord. Off. J. Mov. Disord. Soc. 19, 1102–1106.
Zuardi, A.W., Crippa, J. a. S., Hallak, J.E.C., Pinto, J.P., Chagas, M.H.N., Rodrigues, G.G.R., Dursun, S.M., and Tumas, V. (2009). Cannabidiol for the treatment of psychosis in Parkinson’s disease. J. Psychopharmacol. Oxf. Engl. 23, 979–983.