Essential hypertension: could the basic defect be in blood supply of vasomotor centre?

Various factors have been implicated in the pathogenesis of essential hypertension, although the exact cause of essential hypertension is still unknown. In this paper it is suggested that the basic pathology in essential hypertension may be an inherited defect in the blood supply of that part of reticular formation of rostral ventrolateral medulla which contains the pressor area. The posited defect is one in which the arterial branch supplying blood to the above-mentioned pressor area of vasomotor center arises from an artery which is stenosed. The other branches of this stenosed artery supply adjacent areas of medullary reticular formation concerned with other neurological functions. Due to this stenosis there is ischaemia of the pressor area resulting in increased systemic arterial pressure. During stress, the blood requirement of adjacent areas of the reticular formation (whose function is still not clearly defined) may increase, thus further decreasing blood flow to vasopressor area and increasing the cerebral ischaemic response. After a prolonged time, this increased blood pressure can cause hyaline arteriolar nephrosclerosis in kidney, which may participate in the maintenance of elevated systemic arterial pressure.