Further studies of arterial hypertension.

Abstract

In a previous paper 1 the results of experiments were reported which showed that, in dogs, a marked rise of arterial blood pressure followed reductions of renal substance varying from 50 to 85 per cent. The injury to the kidney was, in most cases, caused by ligation of one renal artery alone, or combined with ligation of one or more branches of the opposite renal artery. When, however, the corresponding reduction of renal tissue was accomplished by unilateral nephrectomy, no rise in blood pressure occurred. In none of these experiments could evidence of renal insufficiency be obtained by examination of the blood for retention of urinary constituents; nor was there any striking alteration of the ability of the remaining functioning kidney-tissue to excrete phenolsulphonphthalein.

The suggestion, therefore, rises that the rise in blood pressure was occasioned by damaged renal tissue left within the body and, if this is true, it becomes necessary to determine whether this pressor action is characteristic for renal tissue alone under these conditions or is common to all tissue undergoing similar degeneration.

The following five groups of experiments summarized in tabular form were performed in the attempt to throw light upon these two points.

The blood pressure was taken without anesthesia by the auscultotory method, using a regular Bowle's stethoscope and the specially constructed cuff of the Koll's apparatus 2 . This method does not appear as satisfactory as that devised by Kolls, but as the table shows, it seems to be relatively accurate. The Kolls method has so far been impracticable in China because of the deleterious effect of the climate on the thin rubber bulb.

From 10 to 30 blood pressure determinations were made before any experimental procedures were undertaken.