Konda N
Nihon Naibunpi Gakkai Zasshi. 1975 Jun 20;51(6):524-45. doi: 10.1507/endocrine1927.51.6_524.
By the earlier studies it has been shown that electrical stimulation of some brain areas such as the medial amygdala and the medial septum increased multiple unit activity (MUA) in the medial preoptic area (MPO) and the arcuate nucleus (ARC) and resulted in gonadotropin release and/or ovulation. On the basis of this evidence, the present study was made to elucidate the effects of stimulation of the forebrain-limbic inhibitory systems on MUA in the MPO and the ARC in relation to the control of gonadotropin release using Wistar female rats. 1) In proestrous rats, electrical stimulation of the basolateral complex of amygdala (1-AMYG), the anterior amygdala (AAA), the hippocampus (HPC), the anterior hippocampus (HIA) and the ventral and lateral part of the central gray matter at the caudal midbrain level (CG) depressed the MUA levels in both the MPO and the ARC in almost of all cases. In the same experiments using ovariectomized and no-primed rats, it was observed that electrical stimulation of the above-mentioned areas was also successful to depress the MUA levels in the MPO and the ARC. But the incidence of inhibition was somewhat lower than that of in proestrous rats. 2) Simultaneous stimulation of the HPC and the 1-AMYG decreased in their inhibitory effects on the MUA in the MPO and the ARC which were apparently observed through the separate stimulation. This was true in combined stimulation of the CG and the 1-AMYG or of the CG and the HPC. It seemed that inhibitory effect on gonadotropin release which was induced by the separate stimulation was cancelled by the combined stimulation. 3) The 1-AMYG and the HPC seemed to form an inhibitory feedback circuit, excitation of a site inhibiting the other. 4) In ovariectomized rats, electrical stimulation of the 1-AMYG or the HPC decreased the MUA levels in the MPO and the ARC after the estrogen injection even in the case that facilitatory effects were observed before estrogen administration. It seemed that inhibitory effects of these inhibitory areas on the hypothalamic activity were enhanced under the dominant influence of estrogen. 5) After an injection of atropine, electrical stimulation of the HPC increased the MUA levels in the MPO and the ARC, while the stimulation of the same sites decreased when no treatment. On the other hand, atropine did not alter the effects of 1-AMYG stimulation on the MUA in the MPO and the ARC. It seems that the forebrain-line inhibitory systems have more important roles in the control of gonadotropin release than it has been assumed, through inhibiting the electrical activity in the MPO and the ARC.
早期研究表明，电刺激某些脑区，如内侧杏仁核和内侧隔区，可增加内侧视前区（MPO）和弓状核（ARC）的多单位活动（MUA），并导致促性腺激素释放和/或排卵。基于这一证据，本研究使用Wistar雌性大鼠，旨在阐明前脑-边缘抑制系统刺激对MPO和ARC中MUA的影响，以及与促性腺激素释放控制的关系。1）在动情前期大鼠中，电刺激杏仁核基底外侧复合体（1-AMYG）、前杏仁核（AAA）、海马体（HPC）、前海马体（HIA）以及尾侧中脑水平中央灰质的腹侧和外侧部分（CG），在几乎所有情况下均降低了MPO和ARC中的MUA水平。在对去卵巢且未进行预处理的大鼠进行的相同实验中，观察到电刺激上述区域也成功降低了MPO和ARC中的MUA水平。但抑制发生率略低于动情前期大鼠。2）同时刺激HPC和1-AMYG，其对MPO和ARC中MUA的抑制作用较单独刺激时有所减弱。CG与1-AMYG或CG与HPC联合刺激时也是如此。似乎单独刺激所诱导的对促性腺激素释放的抑制作用被联合刺激抵消了。3）1-AMYG和HPC似乎形成了一个抑制性反馈回路，一个位点的兴奋会抑制另一个位点。4）在去卵巢大鼠中，即使在雌激素注射前观察到促进作用，电刺激1-AMYG或HPC在注射雌激素后仍会降低MPO和ARC中的MUA水平。似乎在雌激素的主导影响下，这些抑制区域对下丘脑活动的抑制作用增强了。5）注射阿托品后，电刺激HPC会增加MPO和ARC中的MUA水平，而未处理时刺激相同位点则会降低MUA水平。另一方面，阿托品并未改变电刺激1-AMYG对MPO和ARC中MUA的影响。似乎前脑-边缘抑制系统通过抑制MPO和ARC中的电活动，在促性腺激素释放控制中发挥着比以往认为的更重要的作用。
