Effects of orexins on myoelectric activity of sphincter of Oddi in fasted rabbits

Aim： To investigate the effects of peripheral orexins on myoelectric activity of the sphincter of Oddi （SO） in fasted rabbits, and carry out a preliminary investigation into the mechanisms underlying these effects. Methods： Myoelectric activity of SO in fasted rabbits was recorded before and after intravenous or local application of orexins. The effects of intravenous atropine on orexin-increased myoelectric activity of SO were tested. Results： Myoelectric activity of SO was activated by both intravenous and local injection of orexin-A or orexin-B. Intravenous application of atropine completely inhibited the excitatory effect of orexins on SO. Conclusion： Peripheral application of orexins can increase myoelectric activity of SO in fasted rabbits, which is partially associated with the activation of the cholinergic pathway.