Niesink R J, Vanderschuren L J, van Ree J M
Dept. of Pharmacology, Rudolf Magnus Institute for Neurosciences, Faculty of Medicine, Utrecht University, The Netherlands.
Neurotoxicology. 1996 Fall-Winter;17(3-4):905-12.
Changes in analgesia, play behavior, sexual behavior and responsiveness to stress and stimulants have been reported in rodents treated in utero with opiates. During development the endogenous opioids and opioid receptors are present in a tonic balance in the mammalian nervous system. The development of this balance is particularly sensitive to prenatal administration of opioid agonists and antagonists. The motivational and rewarding aspects of play behavior are probably controlled by endogenous opioid systems; low doses of opioids stimulate play behavior, whereas administration of opioid antagonists attenuates play behavior. We have analyzed the effect of morphine administration during the prenatal development of endogenous opioid systems on play behavior in juvenile rats. The doses of morphine used neither affected gestation of pregnant mother rats nor sensorimotor development of the juvenile rats. Levels of social play were elevated in juvenile rats after prenatal exposure to morphine. Social behaviors not related to play and non-social activities were not affected by the prenatal treatment procedure. To study these changes in more detail, social play was investigated using a sequential analysis in prenatally morphine-and saline-exposed pairs. The sequential structure of behavior was not altered by the in utero exposure to morphine. Quantitatively, increases in behavioral transitions were found between behaviors related to play. The prenatal morphine treatment did not affect transitions between behaviors not related to play. It is concluded that the prenatal exposure to morphine did not affect mechanisms underlying play behavior itself, but is probably affecting more general phenomena like reward or motivation to play.
据报道，子宫内用阿片类药物处理过的啮齿动物在镇痛、玩耍行为、性行为以及对应激和兴奋剂的反应方面会发生变化。在发育过程中，内源性阿片类物质和阿片受体在哺乳动物神经系统中处于一种紧张性平衡状态。这种平衡的发育对产前给予阿片类激动剂和拮抗剂尤为敏感。玩耍行为的动机和奖赏方面可能受内源性阿片系统控制；低剂量阿片类药物刺激玩耍行为，而给予阿片拮抗剂则会减弱玩耍行为。我们分析了在内源性阿片系统产前发育期间给予吗啡对幼鼠玩耍行为的影响。所用吗啡剂量既不影响怀孕母鼠的妊娠，也不影响幼鼠的感觉运动发育。产前接触吗啡后，幼鼠的社交玩耍水平有所提高。与玩耍无关的社交行为和非社交活动不受产前治疗程序的影响。为了更详细地研究这些变化，我们对产前暴露于吗啡和生理盐水的幼鼠对进行了序列分析以研究社交玩耍行为。子宫内接触吗啡并未改变行为的序列结构。从数量上看，与玩耍相关的行为之间的行为转换有所增加。产前吗啡治疗并未影响与玩耍无关的行为之间的转换。得出的结论是，产前接触吗啡并未影响玩耍行为本身的潜在机制，但可能影响了诸如奖赏或玩耍动机等更普遍的现象。
