CNR1 and neurodegenerative disease: Considering the ability of cannabinoid receptors to form heteromers that may constitute therapeutic targets, as already postulated for neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease [30,58], this work aimed to adequately characterize the formation of complexes between CB1 or CB2 and GPR55 receptors in the CNS and to evaluate whether the expression of these receptor complexes is affected in MS.