Morphological Studies on the Autonomic Nervous System of Hypertensive Rats. V.Various Morphological Observations on the Superior Cervical Sympathetic Ganglia of Rats with Experimentally Induced Hypertension.

Histometric, enzyme histochemical, and fluorescence and electron microscopic studies were performed on the superior cervical sympathetic ganglia of rats with experimentally induced hypertension and those of normotensive control rats. DOCA hypertension, renal infarction hypertension, and cerebral hypertension were induced in normotensive Wistar strain rats (with original blood pressures below 150 mmHg). The hypertensive animals were sacrificed and examined, some in the acute and some in the chronic stage of hypertension, and their ganglia were compared with those of normal controls. 2. The rats with DOCA implantation and l% saline ingestion developed sustained hypertension beginning after about three weeks of treatment and lasting till death (DOCA hypertension). The body weight of these animals was significantly lower than that of the controls through the experimental period. The rats with bilateral ligation of the posterior branches of the renal arteries became hypertensive within a few days after operation, and hypertension was maintained thereafter (renal infarction hypertension). The body weight of these animals was lower than that of the controls only in the acute stage. The rats with bilateral internal carotid artery dissection developed hypertension one week after operation (cerebral hypertension). It was slightly labile in the acute stage, but sustained in the chronic stage. No gross physical changes were found in this group. 3. Histometrically, the following findings were noted. The sympathetic ganglia of the rats with DOCA hypertension showed no remarkable changes in the acute stage, but the ganglia tended to increase in weight and the nerve cell bodies became significantly enlarged in the chronic stage. In the acute stage in rats with renal infarction hypertension, only the ganglia weighed more than those of the controls. However in the chronic stage, the weight and volume of the ganglia, and the size of the nerve cells and their nuclei, were significantly greater than those of the controls. The rats with cerebral hypertension in the acute stage had heavier ganglia and larger nuclei than normal rats. In the chronic stage, there was definite hypertrophy of both ganglia and neurons. 4. Enzyme histochemical findings were as follows.