STIMULATION EXPERIMENTS ON THE AMYGDALOID NUCLEAR COMPLEX AND RELATED STRUCTURES EFFECTS UPON THE RENAL VOLUME, URINARY SECRETION, MOVEMENTS OF THE URINARY BLADDER, BLOOD PRESSURE AND RESPIRATORY MOVEMENTS

Summary We hove sought to verify the possible role of the amygdala effecting on the renal function and urinary bladder movements by investigating the changes of the renal volume, urinary secretion, movements of urinary bladder, blood pressure, heart rate and respiration induced by stimulation on the basal telencephalon and diencephalon, especially on the amygdaloid nuclear complex and obtained following results: 1) I Decrease in the renal volume and retardation of the urine outflow were recognized by electrical and chemical stimulations of the medial principal nucleus (T of Völsch or medial small‐celled part of the basal nucleus of Johnston ) and perhaps also by stimulation of the cortical nuclens 'B of Völsch ), but not by stimulation or, the cortex of the piriform lobe or periamygdaloid cortical area ( Rose's area periamygdalaris). Since isolated stimulation of the lateral or intermediate principal nucleus (M or T'. was difficult and in our stimulation experiments all another adjadent nuclear structures were injured, any definite conclusion could not be determined upon these nuclei. 2) Responses in the renal volume can be classified in several types. These, however, seem to have no correlation with the stimulated subnuclei, but seemingly stand in an intimate relationship with the types of change in the blood pressure caused by amygdalar stimulation. 3) Stimulation experiments of the arnygdala after severing various neighboring regions revealed that the impulse concerned may be conveyed immediately through the fibers passing across the optic tract to reach the hypothalamic nuclei on the same side. 4) Splanchnicotomy cusses generally increase in the urine dropping from the ureter. Stimuliaton on the‐ medial part of the amygdala after splanchnicotomy did also result in a decrease in the renal volume, while the urine secretion showed in one example a tendency toward increasing, but in another examples on remarkable alteration. 5) Experiments on hypophysectomized dogs produced also a slight diminution of the renal volume and an increasing effect upon the urine secretion. No remarkable effects were found after thyroidectomy. 6) Inhibitory effects upon the bladder movements may be elicited by stimulation of the medial principal nucleus (T of Völsch ) as well as of the cortical nucleus (B). After cessation of stimulation, an abnormally strong contraction of the bladder can be occasionally observed or in some case;, mainly in repeated stimulations, a long inhibitory period was seen. Accelerated effects was recognized on the contrary by stimulation of the intermediate principal nucleus (T') with some after effects as diminution of some successive contractions. 7) Stimulations on another subnuclei of the amygdala and on the periamygdaloid cortical area were not effective upon urinary bladder movements, while stimulation of a certain part of the hippocampus cause micturition or a remarkable contraction of the urinary bladder. 8) Stimulation of the posterior orbital area of the frontal lobe produces an inhibitory effect upon respiration as indicatd by Bailey and Sweet (1940), but no effects upon the bladder movements. The region bordering medially to this area lying medial to the fissure rhinica lateralis evokes, however, a slight contraction of the urinary bladder. 9) Severing experiments revealed also that the impulse may be conveyed from the amygdaloid nucleus to the bladder by way of the similar fiber path to reach the hypothalamic nuclei as in the case of change in the renal volume and urine secretion. 10) Experiments on the blood pressure. heart rate and respiratory movements were performed with the use of the square wave generator by various parameters of stimulation constating the‐ results of our previous reports (1953, 1953). The results were aualitatively of similar nature. In some cases, however, I reversal response it the blood pressure was recorded by stimulation with low frequency pulses. 11) Most characteristic patterns of the‐ amygdaloid stimulation experiments effecting upon the renal volume, urine secretion and the move. ments of the urinary bladder were discussed reviewing the results of experiments of the previous authors on another brain regions. 12) Stimulation of a certain part of the hippocampus may cause in addition to the above mentioned contraction of the urinary bladder, generally a fall in the blood pressure and mydriasis as parasympathetic responses. A similar phenomenon in the blood pressure may be elicited from stimulation of the putamen. The results of stimulation upon the hypothalamic b‐sympathetic or c‐parasympathetic zone were identical with the reports of the previous authors, seemingly also of equal grade and pattern in comparison with the results obtained from stimulation on the amygdaloid region.