Contribution of Forebrain Mechanisms in the Maintenance of Deoxycorticosterone Acetate-Salt Hypertension

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Abstract
A considerable amount of experimental evidence exists suggesting that forebrain structures are involved in the pathogenesis of hypertension. In particular, the paraventricular nucleus of the hypothalamus (PVH) has been implicated in the development and maintenance of the elevated arterial pressure (AP) in several different experimental models of hypertension. The present study was done to determine whether the PVH contributed to the maintenance of the increased AP in deoxycorticosterone acetate-salt (DOCA) hypertension in the rat. In the first series of experiments, using the hexokinase histochemical method, increased metabolic activity was observed in the PVH of DOCA-salt hypertensive rats. In addition, the lateral septal nucleus, median preoptic nucleus, bed nucleus of the stria terminalis, subfornical organ, nucleus circularis, supraoptic nucleus and central nucleus of the amygdala were observed to have increased metabolic activity. In the second series of experiments, bilateral lesions of the PVH resulted in a transient reduction in the elevated AP of DOCA-salt hypertensive animals. However, within approximately a week, the level of AP was not significantly different from sham-PVH lesioned DOCA-salt hypertensive rats. These data suggest that the PVH may be one of several forebrain structures that contributes to the elevated sympathetic activity in DOCA-salt hypertension and when absent other pressor systems are recruited to maintain the elevated AP.