Effect of Hypothalamic Stimulation on the Adrenaline Sectreion of the Adrenal Glands in Cats

In cats, anesthetized with evipan-sodium, the hypothalamus was stimulated electrically, inserting the electrode with the aid of Horsley-Clarke stereotaxic instrument. The adrenal vein blood specimens were collected without opening the abdominal cavity and the adrenaline content in the blood specimens was estimated. The blood pressure was recorded simultaneously. By the stimulation of the ventro-medial as well as the ventro-lateral hypothalamic portion, the blood pressure elevated abruptly. The adrenaline secretion rate before stimulation was 0.03-0.1μg. per kg. per min. and during stimulation it increased remarkably to reach 0.5-5μg. per kg. per min. Soon after stimulation the adrenaline secretion rate resumed in most of cases its initial value. The authors wish to express their thanks to Prof. M. Wada for his helpful advices during this work.