Stress induced Straub tail elevation. Further behavioral evidence in rats for the involvement of endorphins in stress.

Adult male Sprague-Dawley rats briefly immersed in cold water and forced to swim showed Straub tail elevation, a typical sign of opiate stimulation, upon removal. The presence of Straub tail was a function of degree of immersion and was reversed by naloxone. This suggests the Straub tail response may be a novel behavioral index of stress-induced endorphin release.