Ibipinabant is another first-generation antagonist/inverse agonist of CB1Rs; it appears to be as effective as rimonabant in decreasing the intake of a highly palatable diet in Wistar rats, but with a lower degree of occupancy of brain CB1Rs [228], suggesting that part of the anti-obesity effect of CB1R antagonists/inverse agonists is due to their action on peripheral receptors [229]. This evidence concerns the gene CNR1 and obesity due to melanocortin 4 receptor deficiency.