Cronin G M, Wiepkema P R, van Ree J M
Neuropeptides. 1985 Dec;6(6):527-30. doi: 10.1016/0143-4179(85)90114-3.
Tethered sows continuously performed stereotypies during a substantial part of the day time. A single subcutaneous injection with naloxone significantly decreased the profound stereotypies, while explorative behaviours of pigs were not affected by naloxone. In addition a long-term effect of naloxone was noticed. It is suggested that performing the seemingly purposeless stereotypies may function as an effective strategy in order to cope with the conflict-inducing housing conditions. The present data implicate endorphins in this strategy. The involvement of endorphins in the stereotypies of the sows may be related to the calming, rewarding and dependency-inducing effects of the endorphins.
拴系饲养的母猪在一天中的大部分时间里持续表现出刻板行为。单次皮下注射纳洛酮可显著减少这种严重的刻板行为，而猪的探究行为不受纳洛酮影响。此外，还观察到了纳洛酮的长期效应。研究表明，表现出看似无目的的刻板行为可能是一种有效的策略，以应对引发冲突的饲养条件。目前的数据表明内啡肽参与了这一策略。内啡肽参与母猪的刻板行为可能与内啡肽的镇静、奖赏和诱导依赖作用有关。
