Changes in nucleus tractus spinalis nervi trigemini after temporary occlusion of aorta thoracica in dog.

In a group of seven dogs the thoracic aorta was occluded by means of tourniquet for 30 minutes. After the release of aorta the animals were left living for 6-7 days. The spinal cord and brain stem were treated by Nauta-Gygax method after sacrificing the animals, then the preterminal and terminal degenerations of some ascending spinal systems were analysed. Distinct degenerations in nucleus tractus spinalis nervi trigemini were detected. They originated in lower thoracic and lumbosacral segments of spinal cord. Degenerations were localised in the caudal part of nuclei of trigeminal complex. It looks like the above mentioned projections terminating in nucleus tractus spinalis nervi trigemini are related to tractus spinocerebellaris posterior.