Effect of cyproheptadine on the octopamine-induced responses in the mammalian central nervous system

Extracellular recordings have been made from rat thalamic neurones anaesthetized with urethane, 1.5--2 g/kg i.p. Iontophoretically applied octopamine excited certain thalamic neurones in the ventral basal complex while inhibiting others. Both effects were reversibly antagonized by iontophoretically applied cyproheptadine without affecting responses to noradrenaline and dopamine.