Selective serotonin reuptake inhibitors increase the counterregulatory response to acute hypoglycemia and avoid the blunting of the counterregulatory response after recurrent hypoglycemia in rats (Sanders et al., 2008) and humans (Briscoe et al., 2008a,b), indicating that 5-HT plays a vital role in mediating this response. Here, HTR5A is linked to Hypoglycemia.