Br J Pharmacol. 2008 Jan;153(2):271-6. Epub 2007 Oct 8.
Direct Suppression of Autoreactive Lymphocytes in the Central Nervous System Via the CB2 Receptor.
The cannabinoid system is now recognized as a regulator of both the nervous and immune systems. Although marijuana has been used for centuries for the treatment of a variety of disorders, its therapeutic mechanisms are only now being understood. The best-studied plant cannabinoid, Δ9-tetrahydrocannabinol (THC), produced by Cannabis sativa and found in marijuana, has shown evidence of being immunosuppressive in both in vivo and in vitro. Since THC binds to at least two receptors that are differentially expressed by the immune and nervous systems, it has not been possible to clearly discriminate the biological effects it exerts in the two systems. In addition, endogenous cannabinoids have also been described that bind to both receptors and exert both neuronal and immune modulatory activity. The generation of mice deficient in specific cannabinoid receptors has facilitated studies to discriminate cannabinoid-specific functions. This review focuses on the function of the cannabinoid receptor 2 (CB2), primarily expressed in the immune system, in regulating T cell effector functions associated with autoimmune inflammation in the central nervous system (CNS).
PMCID: PMC2219523, PMID: 17922025 [PubMed - indexed for MEDLINE]
Br J Pharmacol. 2007 Nov;152(5):649-54. Epub 2007 Sep 24.
Cannabinoid Control of Neuroinflammation Related to Multiple Sclerosis.
Baker D, Jackson SJ, Pryce G.
The cannabis plant (Cannabis sativa) has been known by many names but the question remains 'Can we call it medicine?' There has been renewed interest in the value of cannabis for the control of neuroinflammatory conditions such as multiple sclerosis, where it has been shown to have some effect on spasticity and pain both experimentally and in clinical trials in humans. However, in addition to symptom control potential, the question remains whether cannabinoids can modify the neuroinflammatory element which drives relapsing neurological attacks and the accumulation of progressive disability. In experimental studies it has been recently shown that synthetic cannabinoids can affect the immune response both indirectly via CB1 receptor-mediated signalling nerve centres controlling the systemic release of immunosuppressive molecules and directly by CB2 receptor-mediated inhibition of lymphocyte and macrophage/microglial cell function. However, these immunosuppressive possibilities that would limit the frequency of relapsing attacks will probably not be realized clinically, following use of medical cannabis, due to dose constraints. However, cannabinoids may still affect the glial response within the damaged central nervous system, which facilitate the slow, neurodegenerative processes that account for progressive neurodegeneration, and therefore may have utility in addition to value of cannabis-related drugs for symptom control.
PMCID: PMC2190016, PMID: 17891167 [PubMed - indexed for MEDLINE]
Br J Pharmacol. 2008 Jan;153(2):216-25. Epub 2007 Sep 24.
CB2 Cannabinoid Receptors as an Emerging Target for Demyelinating Diseases: from Neuroimmune Interactions to Cell Replacement Strategies.
Arévalo-Martín A, García-Ovejero D, Gómez O, Rubio-Araiz A, Navarro-Galve B, Guaza C, Molina-Holgado E, Molina-Holgado F.
Laboratory of Neuroinflammation, Unidad de Neurología Experimental, Hospital Nacional de Parapléjicos (SESCAM), 45071 Toledo, Spain.
Amongst the various demyelinating diseases that affect the central nervous system, those induced by an inflammatory response stand out because of their epidemiological relevance. The best known inflammatory-induced demyelinating disease is multiple sclerosis, but the immune response is a common pathogenic mechanism in many other less common pathologies (e.g., acute disseminated encephalomyelitis and acute necrotizing haemorrhagic encephalomyelitis). In all such cases, modulation of the immune response seems to be a logical therapeutic approach. Cannabinoids are well known immunomodulatory molecules that act through CB1 and CB2 receptors. While activation of CB1 receptors has a psychotropic effect, activation of CB2 receptors alone does not. Therefore, to bypass the ethical problems that could result from the treatment of inflammation with psychotropic molecules, considerable effort is being made to study the potential therapeutic value of activating CB2 receptors. In this review we examine the current knowledge and understanding of the utility of cannabinoids as therapeutic molecules for inflammatory-mediated demyelinating pathologies. Moreover, we discuss how CB2 receptor activation is related to the modulation of immunopathogenic states.
PMCID: PMC2219542, PMID: 17891163 [PubMed - indexed for MEDLINE]