Although paliperidone-related hyperglycemia has been extensively examined, the underlying mechanisms have not yet been elucidated. We investigated the effects of a single intravenous injection of paliperidone (0.2, 0.4, or 0.6 mg/kg) on serum concentrations of glucose and other endogenous metabolites in rats. We also examined the effects of a single intravenous injection of paliperidone (0.4 mg/kg) on AMP-activated protein kinase (AMPK) activity in the hypothalamus and liver. To clarify the relationship between AMPK activity and adrenaline secretion, the effects of berberine, which inhibits hypothalamic AMPK, on paliperidone-induced hyperglycemia were assessed. Significant increases were observed in serum glucose, adrenaline, and insulin concentrations following intravenous injections of paliperidone at doses of 0.4 and 0.6 mg/kg. A propranolol pretreatment attenuated paliperidone-induced increases in serum concentrations of glucose, but not adrenaline. Significant increases were also noted in phosphorylated AMPK concentrations in the hypothalamus following the administration of paliperidone at a dose of 0.4 mg/kg. A berberine pretreatment attenuated paliperidone-induced increases in blood concentrations of glucose, adrenaline, and insulin and phosphorylated AMPK concentrations in the hypothalamus. Collectively, the present results demonstrated that an acute treatment with paliperidone induced hyperglycemia, which was associated with the effects of hypothalamic AMPK activation on the secretion of adrenaline.
Keywords: AMP activated protein kinase (AMPK); adrenaline; berberine; hyperglycemia; paliperidone.