About this Research Topic
Major advances have been achieved with the discovery of the ubiquitous endocannabinoid system (ECS) that is involved in almost all aspects of mammalian physiology and pathology. The ECS consists of endocannabinoids (eCBs), metabolic enzyme machinery, and two well-characterized cannabinoid receptors (CB1Rs and CB2Rs). We now know that both CB1Rs and CB2Rs are the most abundant GPCRs and differentially distributed throughout the body. The functional neuronal expression of CB2Rs has been less well characterized in comparison with CB1Rs because CB2Rs were found predominantly in cells of immune origin, and was considered as peripheral cannabinoid receptors.
This concept has been challenged by the identification of CB2Rs in different brain regions, significantly modifying the landscape, and pointing out its role in a wide variety of central physiological functions and pathological conditions. Others and we have now demonstrated the expression of CB2Rs in neurons, microglia, astroglia and endothelia cells in different brain regions providing a basis for continued studies of the CNS effects of CB2Rs.
When compared to CB1Rs, CNS CB2Rs are expressed at lower levels, but they are dynamic, inducible, can be upregulated, properties exploitable for neuroprotection and in neuropathological conditions. Progress in unraveling CNR2 genomic structure, its polymorphic nature, sub-type specificity, and variations (SNPs and CNVs) from mice to human subjects that confer vulnerabilities allows further opportunities for continued studies and clinical trials targeting CB2Rs in conditions of neuro-immuno-microbiome disorders.
Indeed, the findings collected to date support a significant function of this cannabinoid CB2 receptor in anxiety, depression, schizophrenia, addiction, Parkinson, Alzheimer, and additional neurodegenerative diseases.
In this Research Topic, we include original and review articles regarding new advances about the role of CB2Rs in a variety of clinical conditions, with special emphasis on psychiatry and its potential as a new therapeutic target for the treatment of different psychiatric disorders.
Keywords: Psychiatric disorders, CB2r, Biomarker, Neurological disorders, Neurodegenerative disorders
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