CNR1 and obesity due to melanocortin 4 receptor deficiency: In the past several years, our group and others have provided evidence that obesity is associated with increased eCB tone in the brain and plasma, altered expression of cannabinoid receptor 1 (CB1 mRNA) and increased eCB levels in the adipose tissue, liver, muscle and pancreas [19,20,21,22,23,24,25,26,27,28].