These results are in complete contrast to recently reported findings by Anderberg et al. that brainstem-derived 5-HT is critical for maintaining the weight loss induced by GLP-1 receptor activation and that central blockade of 5-HT2A receptors attenuates the weight loss and anorexic effects of GLP-1 receptor agonists in rats . Although the dose of PCPA (500 mg/kg) that we used was higher than that (100 mg/kg) used in their study, the PCPA treatment methods were the same between their study and ours . The different results might be due to species-specific differences between rats and mice or the paradoxical phenomenon of 5-HT2A receptor agonists and antagonists .