Abstract: In anesthetized rabbits arrhyt-hmia (mainly ectopie beats)and stiking elevation of arterial blood pressure could be elicited during and after stimulation of mamillary nucleus of the hypothalamus and its surrounding regions with mouopha-sic square wave trains lasted 5 to 15seconds(pulse duration:0.5 to 1 ms;frequency:40 to 70 Hz;current intensity:0.005 to 0.1mA),A redu-ced response of arrhythmia and elevation of blood pressure could still be induced in rabbits with brain stem transected just above the level of dieneephalon and arte-rial blood pressure maintained at a level above 70 mmHg.