INS and Hyperglycemia: The anti-diabetic effect of Trop, proved herein, is in line with a previous in vitro study, in which Trop enhanced insulin release from insulin producing β-cell line.21 Moreover, ondansetron, another 5-HT3 receptor antagonist, was previously reported to revert hyperglycemia induced by the central activation of serotonergic system, indicating the involvement of 5-HT3 receptor subtype in this hyperglycemic effect.42 Trop also normalized both fructosamine and RAGE levels.