AXOTOMY-INDUCED CHANGES IN CYTOCHROME-OXIDASE ACTIVITY IN THE CAT TROCHLEAR NUCLEUS

Following a unilateral section of the trochlear nerve, the effects of axotomy on cytochrome oxidase levels in the trochlear nucleus were stu died. Cytochrome oxidase levels in the axotomized nucleus were signifi cantly lower than in the control nucleus. The maximal decrease was obs erved at 2 weeks. Following partial restoration during weeks 3 and 4, cytochrome oxidase levels stabilized at levels only slightly below nor mal. Since a significant number of trochlear motoneurons die following axotomy, the restoration of cytochrome oxidase levels close to normal suggests that the surviving neurons may compensate for an increased l oad with a permanent increase in oxidative metabolism.