An inexpensive servo-control system for regulating microvascular perfusion pressures in small animals

A simple and inexpensive system for controlling the pressure perfusing the rat cremaster muscle is described. The system utilizes an inflatable cuff-type vascular occluder that is placed around the sacral aorta and is inflated using a syringe pump. The syringe pump is turned on and off by a feedback comparator which senses the pressure downstream of the occluder, and varies the degree of occlusion until the downstream pressure equals a desired setpoint value. Although very simple, this system provides a useful and effective means of altering pressure within the cremaster muscle, and could easily be adapted to other microvascular preparations.