ULTRASTRUCTURAL ALTERATIONS OF SPINAL MOTONEURONS DURING GRADUALLY DIFFERENT ISCHEMIAS IN RABBIT

Spinal ventral horn motoneurons from the lumbar region in the rabbit were examined in the electron microscope during different states of temporary ischemia. Ischemia caused variable effects upon the motoneuron cytoplasmic structures. Alterations were particularly evident in mitochondria and endoplasmic reticulum; a swelling and water uptake by these organelles were observed already after a 5-minute blockade of blood supply. After prolonged ischemia, reproducible structural changes and membrane alterations were especially evident in mitochondria; within a cell, the swollen mitochondria occurred next to less damaged mitochondria. Centrally located ventral horn cells were affected more than peripherally located cells. The structural alterations of the mitochondria and the endoplasmic reticulum are interpreted to be caused by a disturbance of cellular energy and water metabolism. © 1969 Springer-Verlag.