The Granulation of Juxtaglomerular Cells

The pathogenesis of renal hypertension remains a mystery. Renal disease can be severe enough to produce terminal uremia without producing hypertension. On the other hand, hypertension can be induced by partial constriction of the renal artery, and the kidney in question may retain good excretory function. The excretory activities of the kidney seem not to be directly related to its hypertensive or antihypertensive functions. It is therefore inviting to consider aspects of renal anatomy other than those directly and obviously concerned with excretion. Such a structure is the juxtaglomerular apparatus. Certain cells of this juxtaglomerular complex containing discrete secretory granules are found in the wall of the afferent glomerular arteriole, just before it joins the glomerulus. Goormaghtigh studied them many years ago in relation to renal hypertension (2). These cells are in a position which would be particularly affected by changes in intraluminal pressure, such as occurs with Goldblatt clamping. In the classic Goldblatt experiment, the renal artery is partially constricted, producing a decrement in blood pressure downstream. Such a decrement in pressure would reduce the stretch of the walls of the entire renal arborization, including the juxtaglomerular cells residing in the arteriolar walls. These cells, then, could be stretch recep-