Abstract: Stimulation of the mammilary nuclei and their surrounding areas induced cardiac arrhythmia and ischemia as well as a rise of blood pressure in unanesthetized rabbits.Among such changes, the cardiac arrhythmia and isehemia became much weakened in animals under pentobarbital, urethane or α-chloralose anesthsia.In contrast with cardiac effects changes in blood pressure were little influenced by these anesthetics.