Figure 1. A diagram of the arteriograph for mounting middle cerebral arteries from the rat. The gauge on the tubing at right represents a flow meter for measuring perfusion of physiologic saline through the lumen of the artery; the two remaining gauges on either side of the artery represent pressure transducers for measuring the perfusion pressure across the micropipets and the middle cerebral artery. Transmural pressure could be set by raising the two reservoirs to a height above the middle cerebral artery. Luminal perfusion could be adjusted independently of the transmural pressure by providing a perfusion pressure (Delta P).