Helena Cleyde Vanessa Vega, de Oliveira Poletini Maristela, Sanvitto Gilberto Luiz, Hayashi Shinji, Franci Celso Rodrigues, Anselmo-Franci Janete Aparecida
Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto-Universidade de São Paulo, Ribeirão Preto, Brazil.
J Endocrinol. 2006 Feb;188(2):155-65. doi: 10.1677/joe.1.06268.
We have previously shown that the locus coeruleus (LC) is essential for triggering surges of LH. Since LC neurons are responsive to estradiol, which induces progesterone receptor (PR) expression, this study aimed to investigate whether LC neurons express the alpha-estradiol receptor (alphaER) and PR as well as comparing such responses to that observed in the preoptic area (POA). Female rats were perfused at 10, 14 and 16 h on each day of the estrous cycle, and a blood sample was collected for estradiol, progesterone and LH measurements. alphaER- and PR immunoreactive (ir) neurons were detected in POA and LC by immunocytochemistry (ICC). Higher plasma estradiol levels were observed on the day of proestrus, when a smaller number of alphaER-ir POA neurons were detected. An increase in the number of alphaER-ir neurons were observed at 16 h of proestrus and estrus. The number of PR-ir neurons increased in POA only at 16 h of proestrus, and remained unchanged during all other days and times. The profile of alphaER-ir and PR-ir neurons in LC changed over the estrous cycle, with a lower expression on metestrus morning and reaching a peak on diestrus afternoon before declining on the day of proestrus. However, on estrus afternoon, alphaER-ir neurons increased, while PR-ir neurons decreased which may be related to the prolactin surge of estrus. These data show that LC neurons express alphaER and PR and seem to be more sensitive to variations in estradiol than POA. Also, the fluctuation in alphaER and PR observed for LC neurons seems to accompany the hormonal events that occur during the estrous cycle. This profile of alphaER and PR expression might be related to the ability of estradiol and progesterone in regulating the activity of LC neurons, which could be associated to the control mechanisms of LH and prolactin release.
我们之前已经表明，蓝斑（LC）对于触发促黄体生成素（LH）的激增至关重要。由于LC神经元对雌二醇有反应，而雌二醇可诱导孕激素受体（PR）表达，本研究旨在调查LC神经元是否表达α-雌二醇受体（αER）和PR，并将这些反应与在视前区（POA）观察到的反应进行比较。在发情周期的每一天的10、14和16小时对雌性大鼠进行灌注，并采集血样用于测量雌二醇、孕酮和LH。通过免疫细胞化学（ICC）在POA和LC中检测到αER和PR免疫反应性（ir）神经元。在发情前期当天观察到较高的血浆雌二醇水平，此时检测到的αER-ir POA神经元数量较少。在发情前期和发情期的16小时观察到αER-ir神经元数量增加。PR-ir神经元数量仅在发情前期的16小时在POA中增加，在所有其他日期和时间保持不变。LC中αER-ir和PR-ir神经元的分布在发情周期中发生变化，在间情期早晨表达较低，在动情后期下午达到峰值，然后在发情前期当天下降。然而，在发情期下午，αER-ir神经元增加，而PR-ir神经元减少，这可能与发情期的催乳素激增有关。这些数据表明，LC神经元表达αER和PR，并且似乎比POA对雌二醇的变化更敏感。此外，在LC神经元中观察到的αER和PR的波动似乎与发情周期中发生的激素事件相伴。这种αER和PR表达模式可能与雌二醇和孕酮调节LC神经元活性的能力有关，这可能与LH和催乳素释放的控制机制相关。
