MIF-1 TFA (Melanostatin, 1 mg/kg; i.p.; once, for 1 hour; male Wistar rats) modulates the analgesic effects, including stress-induced analgesia (SIA). MIF-1 TFA (Melanostatin, 1 mg/kg; i.p.; daily, for 8 weeks; Sprague-Dawley rats) attenuates spiroperidol-induced impairment of development of striatal dopamine D2 receptors in rats.