CNR1 and Alzheimer disease: Whereas some authors have reported a significant reduction in the CB1 levels in cortical areas and in neurons distant from senile plaques (Ramírez et al., 2005; Solas et al., 2013), others have described no changes in the expression, distribution, or availability of CB1 receptors in cortex and hippocampus in AD (Benito et al., 2003; Lee et al., 2010; Mulder et al., 2011; Ahmad et al., 2013) or have failed to dissociate CB1 receptor expression changes from normal aging (Westlake et al., 1994).