A system to regulate aortic pressure in the rat

Abstract

A servo-controlled aortic clamp has been designed and used for the first time in the anesthetized rat to control femoral arterial pressure. An electrical schematic is given and details of the mechanical clamp used to compress the abdominal aorta are shown. The system has a long-term (30 min) mean pressure control of plus or minus 2 mmHg although some 1–2 s transients of plus or minus 3 mm may occur. It responds to a desired step change in pressure in less than 2 s. The system allows accurate and convenient control of aortic pressure and minimizes the technical difficulties encountered when one attempts similar control by manual means. It therefore facilitates investigation of the effect of transient or steady-state changes in arterial pressure on organ function, e.g., autoregulation of renal blood flow and glomerular filtration rate.