Department of Psychology, Rutgers-The State University of New Jersey, New Brunswick, New Jersey 08903, USA.
J Neuroendocrinol. 1991 Dec 1;3(6):591-6. doi: 10.1111/j.1365-2826.1991.tb00323.x.
Abstract To determine whether the motorically-active and -inactive components of maternal behavior in rats are differentially affected by dopamine, we administered haloperidol, a dopamine receptor antagonist, to lactating rats on day 7 (+/-1) post-partum, 3 h after dam-litter separation and 1 h before their reunion. Compared to treatment with saline or domperidone, a peripherally-active dopamine antagonist, haloperidol treatment inhibited retrieval and licking of pups in a dose-dependent manner and hastened the onset of nursing behavior, but impaired the high crouch posture at the highest doses (8 and 10 mg/kg). Also, litters of dams treated with 0.2, 0.4, or 1.0 mg/kg haloperidol gained almost twice as much weight as litters of controls or of dams treated with 5 to 10 mg/ kg haloperidol. To determine whether the milk ejection pattern accounts for differential litter weight gain after moderate and high doses of haloperidol, milk ejections were assessed by pup stretch and nipple-switching responses for 30 min after the onset of crouching following a 4 h dam-litter separation on day 12 or 13 post-partum. The litters of dams treated with 1 or 3 mg/kg haloperidol had substantially greater litter weight gains than litters of control dams or of dams treated with 5 mg/kg haloperidol. The smaller litter weight gain of 5 mg/kg haloperidol litters was due to a retardation of milk ejections in their dams, while the smaller gain of control litters was due, at least in part, to greater behavioral activation by their dams. Non-dopaminergic effects of large doses of haloperidol (>/=5 mg/kg) may have reduced the display of the high crouching posture during nursing and contributed to the retardation of milk ejections. Thus, dopamine is necessary for the motorically-active components of maternal behavior, but its inhibition may be necessary for the assumption of the immobile nursing postures and for maximal litter weight gains. We hypothesize that extra-hypothalamic as well as tuberoinfundibular dopaminergic systems are inactivated by the suckling stimulus.
为了确定多巴胺是否对大鼠产后行为的运动活跃和不活跃成分产生不同的影响，我们在产后第 7 天（±1 天），在母鼠与幼崽分离 3 小时后并在团聚前 1 小时，给哺乳期大鼠注射了氟哌啶醇，一种多巴胺受体拮抗剂。与生理盐水或外周活性多巴胺拮抗剂多潘立酮相比，氟哌啶醇处理以剂量依赖性方式抑制幼崽的检索和舔舐，并加速哺乳行为的开始，但在最高剂量（8 和 10 mg/kg）下损害了高蹲伏姿势。此外，用 0.2、0.4 或 1.0 mg/kg 氟哌啶醇处理的幼崽体重增加了近两倍，而对照组或用 5 至 10 mg/kg 氟哌啶醇处理的幼崽体重增加了两倍。为了确定中等和高剂量氟哌啶醇后乳汁喷射模式是否会导致不同的窝重增加，我们在产后第 12 或 13 天，在母鼠与幼崽分离 4 小时后，通过幼崽伸展和乳头切换反应评估了 30 分钟的乳汁喷射情况，以评估蹲伏后的开始。用 1 或 3 mg/kg 氟哌啶醇处理的母鼠的窝重增加明显大于对照组或 5 mg/kg 氟哌啶醇处理的母鼠的窝重增加。5 mg/kg 氟哌啶醇处理的窝重增加较小是由于其母鼠的乳汁喷射延迟，而对照组窝重增加较小至少部分是由于其母鼠的行为活动增加。大剂量氟哌啶醇（≥5 mg/kg）的非多巴胺能效应可能会减少哺乳期间的高蹲伏姿势，并导致乳汁喷射延迟。因此，多巴胺是产后行为的运动活跃成分所必需的，但它的抑制可能是假设不动的哺乳姿势和获得最大窝重所必需的。我们假设，除了下丘脑以外的，以及结节漏斗多巴胺能系统，都会被吸吮刺激所抑制。
