Incidence of degenerate fibres in the dorsal column nuclei after ligation of the abdominal aorta.

It was investigated the incidence of damaged nerve fibres in the gracile nucleus and the cuneate nucleus of the dog following an intermittent ligation of the abdominal aorta and 3-day survival. The incidence of damaged fibres was studied at three levels, i.e. the caudal part of the gracile nucleus, the cell-nest region of the gracile nucleus and the region just before the beginning of the central canal. The largest number of disintegrated nerve fibres was found in the cell-nest region. It was observed, that the incidence of damaged fibres diminished both caudally and cranially. When comparing the region just before the beginning of the gracile nucleus with the caudal part of the gracile nucleus it was stated, that the higher density of decomposed fibres was in the region just below the obex. In common there were fewer disintegrated fibres in the cuneate than in the gracile nucleus.