HTR2A and obesity due to melanocortin 4 receptor deficiency: Though some medications targeting 5-HT2A/2C receptor subtypes have been applied in clinical practice, including blonanserin (5-HT2A receptor antagonist) in schizophrenia [103] and lorcaserin (5-HT2c receptor agonist) in obesity [104], more studies are needed to figure out the function and mechanism of 5-HT2A/2C receptors in the descending pain modulation pathway.