Abstract: (1)Various kinds of arrhythimias could be elicited by stimulation of the hypothalamic mamillary nucleus and its surrounding region with monophasic square pluses train (lasted for 5～10 sec,frequency 50 Hz,duration 0.5 ms,intensity 10～100μA) in rabbits bilaterally cervically vagotomized,anaesthelized with sodium amobarbital(33 mg/kg,i.v) and immobi-lized with faxedil.(2)The arrhythimia could be partially or completely arrested by stimula-tion of the central end of cervical vagus.The same inhibitory effect could be elicited by forced inflation of the lungs.(3)Forced distension of the stomach,stimulation of the subdiaphrag-matic portion of the vagi,of the superior laryngeal nerves,of sciatic nerve or.unilateral deep peroneal nerve could not arrested the arrhythimias.(4)A discussion on the central mecha-nism of inhibitory effect of stimulation of the vagus on the arrhythimias was given.

Key words: hypothalamus, cardiac arrhythmias, vagus