Department of Physiology and Endocrinology, Medical College of Georgia, Augusta, Georgia 30912-3000.
Mol Cell Neurosci. 1993 Jun;4(3):292-7. doi: 10.1006/mcne.1993.1037.
The purpose of the present study was to determine the role of non-NMDA receptor-mediated neurotransmission in the expression and production of the progesterone-induced gonadotropin surge in the estrogen-primed ovariectomized adult rat and the preovulatory gonadotropin and prolactin (PRL) surges in the PMSG-primed immature rat. Adult female rats (45 days old) ovariectomized for 2 weeks were implanted with a third ventricular cannulae 1 week before the experiment. Estradiol (5 mug) was injected subcutaneously (sc) at 1700 h on Days 59 and 60 and either vehicle or progesterone (0.5 mg/rat) injected at 0900 h on Day 61. Vehicle or the non-NMDA antagonist DNQX (20 nmol/10 mul) was administered via the third ventricle cannula at 0800 and 1030 h on Day 61. From 1200 to 1800 h on Day 61 blood samples were withdrawn hourly from jugular cannulas for serum LH and FSH measurements. DNQX treatment completely blocked the progesterone-induced LH surge. FSH secretion, on the other hand, was unaffected by DNQX treatment. To study the effect of DNQX on preovulatory gonadotropin and PRL secretion, 27-day-old female rats were implanted with a third ventricle cannulae followed by sc injection of PMSG (8 IU) at 28 days of age (0800 h). On Day 30, either vehicle or DNQX (15 nmol/5 mul) were administered via the third ventricle cannula at 1100 and 1500 h. Groups of rats were sacrificed at 1600, 1800, and 2000 h on Day 30 for serum LH, FSH, and PRL measurements. DNQX treatment significantly attenuated the preovulatory LH surge at 1600 and 1800 h with no effects at 2000 h as the values began to return to baseline. As was the case in the steroid-treated rat, DNQX had no effect on the preovulatory FSH surge. DNQX treatment did, however, significantly attenuate the preovulatory surge of PRL at 1600 and 1800 h. Taken as a whole, the present studies support a role for non-NMDA receptor neurotransmission in the regulation of steroid-induced LH secretion as well as preovulatory LH and PRL surges. In contrast, non-NMDA receptors appear to play little to no role in regulating FSH secretion.
本研究的目的是确定非 NMDA 受体介导的神经传递在雌激素预激去卵巢成年大鼠孕激素诱导的促性腺激素激增以及 PMSG 预激未成熟大鼠促性腺激素和催乳素 (PRL) 激增中的作用。成年雌性大鼠（45 天大）去卵巢 2 周后，在实验前 1 周植入第三脑室套管。在第 59 天和第 60 天的 1700 小时皮下注射雌二醇（5ug），第 61 天的 0900 小时注射载体或孕激素（0.5mg/rat）。第 61 天的 0800 小时和 1030 小时，通过第三脑室套管给予非 NMDA 拮抗剂 DNQX（20nmol/10ul）。从第 61 天的 1200 小时到 1800 小时，从颈静脉套管中每小时抽取血液样本，用于测量血清 LH 和 FSH。DNQX 处理完全阻断了孕激素诱导的 LH 激增。另一方面，DNQX 处理对 FSH 分泌没有影响。为了研究 DNQX 对排卵前促性腺激素和 PRL 分泌的影响，27 天大的雌性大鼠植入第三脑室套管，然后在 28 天大时（0800 小时）皮下注射 PMSG（8IU）。第 30 天，通过第三脑室套管给予载体或 DNQX（15nmol/5ul），时间分别为 1100 小时和 1500 小时。第 30 天的 1600、1800 和 2000 小时，各组大鼠被处死，用于测量血清 LH、FSH 和 PRL。DNQX 处理在 1600 和 1800 小时显著减弱了排卵前的 LH 激增，而在 2000 小时没有影响，因为此时值开始恢复到基线。与接受类固醇治疗的大鼠一样，DNQX 对排卵前 FSH 激增没有影响。然而，DNQX 处理确实显著减弱了排卵前 PRL 激增在 1600 和 1800 小时。总的来说，本研究支持非 NMDA 受体神经传递在调节类固醇诱导的 LH 分泌以及排卵前 LH 和 PRL 激增中的作用。相比之下，非 NMDA 受体似乎在调节 FSH 分泌方面作用不大。
