The cannabinoid receptor type 1 (CB1R) inverse agonist rimonabant, which was in the past used for the treatment of obesity, is also a GPR55 agonist (Kapur et al., 2009; Henstridge et al., 2010), although under some conditions it can behave as an antagonist (Lauckner et al., 2008; Anavi-Goffer et al., 2012). Here, GPR55 is linked to obesity due to melanocortin 4 receptor deficiency.