The effects of acute and chronic stress on motor and sensory performance in male Lewis rats

Any behavioral testing induces stress to some degree. A meaningful interpre tation of behavioral results can be difficult if stress, caused by handling or the testing situation, modifies the experimental outcome. Especially fo r neurological animal models, it is important to know how stress affects mo tor and sensory performance. Therefore, we investigated the effects of vary ing degrees of stress on several motor and sensory tasks that are frequentl y used to assess functional recovery after lesion-induced impairments in ad ult rats. Acute, subchronic, and chronic stress impaired ladder walking and prolonged the duration of grasping a bar. Stress also altered walking patt erns by increasing the base of support and foot rotation and reducing strid e length. Furthermore, chronic stress induced hypersensitivity to painful s timuli, but did not significantly influence the latency to remove sticky pa pers from the hindpaws (sticky paper test). In the light-dark (L/D) test, s tress reduced the latency to enter the dark compartment and enhanced the nu mber of transitions supporting that cold swim stress modifies the animal's level of anxiety. These data point towards a critical influence of acute or chronic stress on motor control and sensory performance of rats, suggestin g that stress might be a critical intervening variable of the outcome of be havioral tests. (C) 2001 Elsevier Science Inc. All rights reserved.