Comparison of initial response to renal artery stenosis in pentobarbitone--anaethetized and conscious dogs.

1. Trained chronically-instrumented dogs were subjected to renal artery stenosis twice. A 50 mmHg stenosis pressure gradient was established while the dogs were conscious or anaethetized with pentobarbitone and prepared for renal surgery. 2. Prior to stenosis, the anaesthetized dogs had significantly higher mean arterial pressure, renal vascular resistance and plasms renin activity than when they were conscious. 3. Twenty-four hours after stenosis, when all dogs were fully conscious, significant elevations in mean arterial pressure and plasma renin activity were seen only in the dogs anaesthetized for stenosis production. Creatinine clearance over this period was also markedly less than after renal artery stenosis of conscious animals. 4. It seems likely that more severe renal artery stenosis is required to produce a given pressure gradient in anaesthetized dogs than in the conscious dogs.