In Vivo: Phentolamine (5-20 mg/kg; i.p.) effectively inhibits the seizures elicited by strychnine (2 mg/kg, i.p.) and attenuates the seizure-potentiating effect of DOPS (4 mg/kg, i.p.) in mouse. Phentolamine (1 mg/kg; i.p.) increases insulin secretion by inhibition of b-cell a2A-adrenoceptors in mouse.