Hormonal regulation of medial preoptic mu-opiate receptor density before and after parturition.
Hormonal regulation of medial preoptic mu-opiate receptor density before and after parturition.
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分娩前后内侧视前μ阿片受体密度的激素调节。
DOI：
10.1159/000126206
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发表时间：
1992
影响因子：
4.1
通讯作者：
Bridges,RS
中科院分区：
文献类型：
--
作者：
HammerJr,RP;Mateo,AR;Bridges,RS
内源性阿片肽作用于内侧视前区（MPOA）似乎参与了哺乳大鼠母性行为的调节。此外，已知MPOA中µ-阿片受体的密度在怀孕期间升高，但在哺乳期降低。在本研究的第一个实验中，我们在妊娠第18、20和22天、产后1小时、产后1和12天的围产期检测视前区µ受体密度。还评估了哺乳期妊娠对μ受体密度的影响。同时测定血浆中雌二醇（E2）、孕酮(P)、催乳素（PRL）的激素浓度。尽管分娩前血浆P水平下降，PRL水平升高，但MPOAµ受体密度在分娩后24小时仍保持升高，随后下降至与去卵巢对照动物相似的水平。受体密度仅在妊娠第22天与PRL水平显著相关，此时PRL水平最高。无论动物是否怀孕，产后第12天MPOAµ受体密度均较低。在任何组的相邻外侧视前区均未观察到任何影响。在第二个实验中，在持续E2/P暴露后，在去除含P的硅胶胶囊后的不同时间，研究激素操作对视前阿片受体密度的影响。除去荚膜后，P水平急剧下降，而MPOA受体密度下降更为缓慢。结果与假设一致，即在缺乏足够激素刺激的情况下，分娩后MPOA中通过受体转换发生μ受体密度降低。MPOA类阿片活性底物的明显降低可能与产后与哺乳期相关的事件有关，因为即使在怀孕和哺乳期大鼠中，µ受体密度也会降低。
Endogenous opioid peptides acting in the medial preoptic area (MPOA) appear to be involved in the regulation of maternal behavior in lactating rats. Moreover, it is known that the density of µ-opiate receptors in the MPOA is elevated during pregnancy, but decreases during lactation. In the first experiment of this study, µ-receptor density in the preoptic area was examined across the periparturitional period on gestation days 18, 20 and 22, at 1 h postpartum and on postpartum days 1 and 12. The effect of pregnancy during lactation on µ-receptor density was also assessed. In addition, plasma hormone concentration of estradiol (E2), progesterone (P), and prolactin (PRL) were determined. While plasma P levels decreased and PRL levels increased prior to parturition, MPOA µ-receptor density remained elevated until 24 h after parturition before declining to reach a level similar to that of ovariectomized control animals. Receptor density was significantly correlated with PRL levels only in gestation day 22 animals, when PRL levels were highest. MPOA µ-receptor density was low at postpartum day 12 whether or not the animal was pregnant. No effects were observed in the adjacent lateral preoptic area in any group. In the second experiment, the effect of hormonal manipulation on preoptic opiate receptor density was examined at various times after removal of Silastic capsules containing P following sustained E2/P exposure. While P levels decreased abruptly following capsule removal, MPOA receptor density declined more gradually. The results are consistent with the hypothesis that a reduction of µ-receptor density occurs in the MPOA following parturition by receptor turnover in the absence of sufficient hormonal stimulation. This apparent reduction of the substrate for MPOA opioid activity could be related to the postparturitional events associated with lactation, since µ-receptor density is reduced even in pregnant, lactating rats.