抄録
1. Enzyme-histochemical study was per-formed on the brain stem of spontaneously hypertensive rats (OKAMOTO and AOKI). Four kinds of enzyme activity (acid phosphatase, diphosphopyridine nucleotide diaphorase, monoamine oxidase and acetylcholine esterase) were examined on 11 nuclei of brain stem of a total of 11 spontaneously hypertensive rats and 11 normotensive control rats of Wistar strain which were subdivided into two groups according to survival duration (40-60 days after birth (Stage I) and 3.5-4 months after birth (Stage II)). Each positive finding in spontaneously hypertensive rats was obtained by comparing it to that of normotensive controls. 2. Mean systolic blood pressure of spontaneously hypertensive rats was significantly higher than that of controls, despite that, it was still in normotensive range in Stage I. Mean body weight did not show any significant difference between spontaneously hypertensive rats and control rats. 3. As to the normal distribution of enzyme activities in the brain stem, an outline of the reactions observed in the brain stem nuclei of normotensive control rats was described. 4. Comparing the results from spontaneously hypertensive rats with those of controls the following findings were obtained. Increased enzyme activities were found in Nucl. originalis dorsalis nervi vagi (acid phosphatase, diphosphopyridine nucleotide diaphorase, monoamine oxidase and acetylcholine esterase in Stage I ; acid phosphatase and diphosphopyridine nucleotide diaphorase in Stage II), Nucl. reticularis lateralis (acid phosphatase in Stage II), Nucl. reticularis pontis oralis (diphosphopyridine nucleotide diaphorase in Stage I), Nucl. reticularis gigantocellularis (diphosphopyridine nucleotide diaphorase in Stage I), Edinger-Westphal's nucleus (monoamine oxidase in Stage I and diphosphopyridine nucleotide diaphorase in Stage II). Decreased activity was observed only in Nucl. reticularis tegmenti (acid phosphatase and diphosphopyridine nucleotide diaphorase in Stage I). 5. From the above-mentioned findings it was assumed that the autonomic nervous sys-tem in the brain stem of the spontaneously hypertensive rats may be in overactive state, being particularly distinct in the parasympathetic zones centering around the dorsal vagal nucleus in this study, though detailed etiological participation of this area could not be clarified.
