Natan L B, Chaillet P, Lecomte J M, Marçais H, Uchida G, Costentin J
Eur J Pharmacol. 1984 Jan 27;97(3-4):301-4. doi: 10.1016/0014-2999(84)90464-3.
In the mouse 'behavioral despair' test the immobility time was shortened by [D-Ala2,Met5]enkephalin at doses which did not modify locomotor activity. Similarly, the inhibitors of the enzymes degrading enkephalins, thiorphan and/or bestatin were effective. Their effect was antagonized by naloxone. We conclude that endogenous enkephalins are implicated in the 'behavioral despair' test.