Heterotopic graft of infant rat brain as an ischemic model for prolonged whole-brain ischemia.

By using a heterotopic brain graft model, we have made histological and electrophysiological studies of the infant rat brain after prolonged ischemia. An infant rat head which had undergone ischemia for more than 90 min, was grafted onto an adult rat by anastomosing the thoracic vessels to the femoral vessels of the host rat. Histological and histochemical studies carried out 10 days after the operation showed that the development of the hippocampus and cerebellum in the grafted brain appeared to be normal. Interneuron growth in the hippocampus and migration of the granule cells in the cerebellum had occurred to a similar extent as in control rats. Extracellular recordings in the hippocampus showed normal characteristics of the postsynaptic potentials including long-term potentiation. This heterotopic graft model would be useful for studying brain function after long periods of ischemia.