LEP and obesity due to melanocortin 4 receptor deficiency: Most interestingly, our findings suggests a diurnal hypothalamic 5-HT2C receptor expression and increases in 5-HT2C receptor editing in the ob/ob mouse model of obesity, which may have important physiological consequences to either the regulation of feeding behaviour through the modulation of 5-HT2C receptor mediated appetite-suppressing effects or compensatory responses to the absence of leptin.