Blood pressure control is central to all bodily functions. There are
many points in the multifaceted cybernetic system wherein hypertension
may be produced. Hypertension is a 'young' disorder whose existence has
been known for less than a century. It is not only extremely prevalent
among every popula- tion, but also deleterious to the health of mankind.
The more we understand about hypertension's harmful effects, the more
urgent is the need for its effective control. The kidney is the central
organ that controls vascular tone and body fluid volume; these two
factors are dominant in determining arterial blood pres- sure. Hence, it
is not surprising to find in hypertensive disorders that there are
abnormalities in the kidneys, functional or anatomical, subtle or overt,
that cause or are the consequence of hypertension. The first suggestion
that the kidney could cause hypertension was made in 1836, before
arterial pressure could even be measured, by Richard Bright. He observed
that cardiac hypertrophy was often present in patients who died of renal
disease. It was, however, Goldblatt and his colleagues in 1934 who
opened the modern era of experimental and clinical research in renal
hypertension. Since then, although far from complete, enthusiastic and
intensive research efforts have greatly improved our understanding of
the nature of renal hypertension.