Kromer W, Dum J E
Eur J Pharmacol. 1980 May 2;63(2-3):195-8. doi: 10.1016/0014-2999(80)90445-8.
Mouse-killing behaviour in rats increased the nociceptive threshold for paw licking, as measured in the hot-plate test. This effect was prevented by the opiate antagonist naloxone, which, on the other hand, had no influence on mouse-killing behavior per se. It is concluded that opioid mechanisms may be involved in changes of nociceptive threshold associated with aggressive behavior.