Cerebral blood flow and edema following carotid occlusion in the gerbil

A technique for measuring focal cerebral blood flow (CBF) and brain specific gravity (SG) in gerbils is described; CO2 reactivity and autoregulation were tested. The mean CBF was 29.5 +/- 4.5 ml/100 gm/min and brain SG 1.0500 +/- 0.0004. Unilateral carotid occlusion resulted in a reduction of flow to 12.8 +/- 5.8 ml/100 gm/min in the ipsilateral hemisphere with little change in the contraleteral hemisphere; there was also a decrease in brain SG. One hour after occlusion, brain edema, as judged by decreased SG, developed at CBF less than 20 ml/100 gm/min and reached maximal levels at 7 +/- 2 ml/100 gm/min. The amount of edema appeared to be related chiefly to the residual post-occlusion flow. With bilateral occlusion, CBF was close to zero and there was no change in SG, indicating that in the "no flow" situation, there is no edema.