Cryoanethesia on postnatal day 1, but not day 10, affects adult behavior and cortical morphology in rats

Hypothermia was used to induce anesthesia in infant rats on postnatal days 1 or 10. In adulthood measures of spatial learning and activity were taken before the brains were harvested for measurement of cortical thickness and dendritic arborization in layer III pyramidal cells in parietal cortex. Cry oanethesia on day 1, but not day 10, produced a small, but statistically si gnificant, impairment in learning a spatial navigation task as well as a re duction in cortical thickness and dendritic arborization. This study confir ms that cryoanesthesia is not a benign treatment in newborn pups but appear s to be without effect in older animals. It is important that all studies u sing cryoanesthesia have sham control animals exposed to the same degree of hypothermia. (C) 2001 Elsevier Science BY All rights reserved.