Effects of Brief Exposure of Male Pheromone on Multiple-Unit Activity at Close Proximity to Kisspeptin Neurons in the Goat Arcuate Nucleus
Effects of Brief Exposure of Male Pheromone on Multiple-Unit Activity at Close Proximity to Kisspeptin Neurons in the Goat Arcuate Nucleus
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DOI：
10.1262/jrd.10-070e
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发表时间：
2011-04-01
影响因子：
1.8
通讯作者：
Okamura, Hiroaki
中科院分区：
文献类型：
--
作者：
Murata, Ken;Wakabayashi, Yoshihiro;Okamura, Hiroaki
雌性山羊暴露于雄性信息素可诱导促性腺激素释放激素(GnRH)的脉动释放。最近，弓状核(ARC)中的Kispeptin神经元被认为是GnRH脉冲发生器的近端来源。在这项研究中，我们研究了信息素对装有针对ARC Kispeptin神经元的记录电极的雌性山羊多单位活动(MUA)的影响。在所有8只山羊中，都观察到了周期性的MUA(MUA Volleys)，这被认为是GnRH脉冲发生器的电生理表现。每只山羊在控制期内计算平均截击间隔(T)，然后在一次定期发生的MUA截击后，以1/4 T、1/2 T或3/4 T的时间间隔暴露于雄性信息素1秒。在暴露后立即观察到MUA的瞬时上升，而不考虑时间。在3/4T的时间内，所有山羊在瞬间上升后60秒内发生MUA凌空抽射。相比之下，1/2T暴露仅有2只山羊发生MUA凌空抽射，而1/4T暴露未能诱导任何山羊发生MUA凌空抽射。这些结果表明，信息素信号向ARC的传输(以瞬时上升为代表)激活了GnRH脉冲发生器。此外，在诱导MUA截击过程中信息素的时间依赖性作用表明，GnRH脉冲发生器对爆发后的信息素信号存在不应期。
Exposure of females to the male pheromone induces pulsatile release of gonadotropin-releasing hormone (GnRH) in goats. Recently, kisspeptin neurons in the arcuate nucleus (ARC) have been suggested to represent the proximate source of the GnRH pulse generator. In this study, we examined the effects of the pheromone on multiple-unit activity (MUA) in female goats fitted with recording electrodes aimed at the ARC kisspeptin neurons. In all eight goats, periodic bursts in MUA (MUA volleys), which were considered to be electrophysiological manifestations of the GnRH pulse generator, were observed. The mean intervolley interval (T) during the control period was calculated in each goat that was then exposed to the male pheromone for 1 sec at timings of 1/4 T, 1/2 T or 3/4 T after one regularly occurring MUA volley. An instantaneous rise in MUA was observed immediately after the exposure regardless of timing. Exposure at a timing of 3/4 T resulted in an MUA volley within 60 sec following the instantaneous rise in all goats. In contrast, an MUA volley was induced in only 2 goats by exposure at 1/2 T, while exposure at 1/4 T failed to induce an MUA volley in any goats. These results suggest that transmission of the pheromone signal to the ARC, represented by an instantaneous rise, activates the GnRH pulse generator. Moreover, the timing-dependent pheromone action in inducing an MUA volley indicates that the GnRH pulse generator has a refractory period for the pheromone signal after the burst.