Repeated swim stress increases pain-induced expression of c-Fos in the rat lumbar cord.

We have previously demonstrated that repeated swim stress produces a long-lasting cutaneous hyperalgesia in rats. We have now looked at c-Fos expression in the spinal lumbar cord of male Sprague-Dawley rats subjected to 10-20 min daily sessions of forced swimming for 3 consecutive days. Control rats were subjected to sham swimming or were completely naive.