Models for studying long-term recovery following forebrain ischemia in the rat. 1. Circulatory and functional effects of 4-vessel occlusion.

The article describes findings obtained by the application of the Pulsinelli-Brierley 4-vessel occlusion ischemic model in 2 rat strains. In one, a high incidence of respiratory arrest was observed after carotid occlusion. In the other, no such problems were encountered but a large fraction of the animals failed to lose consciousness upon arterial occlusion. In these "stuporous" animals, CBF values of major forebrain structures, as measured by a tissue sampling 14C-iodoantipyrine technique, showed considerable scatter with some values approaching 75% of control. However, even in animals which became comatose, flow was variable and occasionally approached 50% of control, the variability being especially pronounced in the hippocampus and the thalamus. It is concluded that the variability in ischemic flow rates must be taken into account when the model is used for studies of pathophysiological events and therapeutic interventions.