1984 年 48 巻 6 号 p. 567-574
To determine the importance of the renal nerves in DOCA-salt hypertension, either renal denervation or a sham-operation was carried out on both DOCA-salt-treated and non-DOCA-treated rats. The systolic blood pressure of the non-DOCA rats remained within normotensive levels, in which the difference in blood pressure levels between the renal denervated and the sham-operated groups was not significant. On the other hand, the blood pressure of the rats treated with DOCA, and having intact renal nerves, began to rise by the end of the first week and rose consistently thereafter, whereas, in the renal denervated DOCA-salt rats, the blood pressure started to rise by the second week and then proceeded to increase gradually. The differences between the sham and the denervated rat groups were significant throughout the four weeks. The mean arterial pressure, directly measured from the caudal artery of conscious rats during the fourth week of this study, was 166±7 mmHg in the sham-operated and 129±4 mmHg in the renal-denervated rats (the data having an 1% significant difference). To test the effects of renal denervation on the natriuresis, pentobarbital-anesthetized rats wee infused intravenously with physiological saline. The renal denervated rats which had received DOCA excreted more sodium than did the sham-operated rats. When the rats were later anesthetized with urethane to allow intracisternal injections of hypertonic saline, the mean blood pressure in renal denervated rat groups was again lower than that of the sham-denervated rat groups. However, subsequent intracisternal injections of 5% saline produced similar pressor responses as well as tachycardia in both DOCA groups. In comparing the non-DOCA with the COCA-treated group, it was found that the degree of pressor response was significantly greater in the latter group. Finally, renal denervation was confirmed by measuring the norepinephrine content of the kidney in the fourth week of the study; the level was significantly lower in the renal denervated than in the sham-operated group. These results suggest that intact renal nerves are important in the development of the DOCA-salt hypertension. ]the depressor effects of renal denervation are not brought about by the elimination of direct vasoconstriction of renal vasculature, but rather as a result of long lasting effects on renal function.
