Hansen S, Köhler C, Goldstein M, Steinbusch H V
Brain Res. 1982 May 6;239(1):213-32. doi: 10.1016/0006-8993(82)90843-5.
It is well known that electrolytic lesions in the medial preoptic area (MPOA) and the lateral hypothalamic area (LHA) seriously impair masculine sexual behavior in the rat. We here report that bilateral infusions of the neurotoxin, ibotenic acid (IBO), in the MPOA were as effective as electrolytic lesions in eliminating copulation whereas no behavioral effects were detected following similar infusions in the LHA. Histological examination of MPOA and LHA following IBO exposure revealed extensive degeneration of neuronal cell bodies with little evidence of non-specific damage. Also, immunohistochemical studies suggested that the serotonergic innervation of the MPOA remained largely intact in spite of IBO treatment; similarly, the damage inflicted by IBO in LHA on tyrosine hydroxylase-immunoreactive fibers in the medial forebrain bundle was insignificant. These data suggest that: (i) the functional integrity of MPOA nerve cell bodies is necessary for the expression of sexual behavior, and (ii) disruption of mating produced by electrolytic LHA lesions is due to disruption of medial forebrain bundle fiber systems. Behavioral observations of non-copulating males suggested that the MPOA injury did not interfere with all aspects of their sexual interaction with the estrous female; rather, they appeared specifically unable to perform the reflexive pelvic thrust pattern normally associated with mounting. We here report, however, that the ability to perform mounts with pelvic thrusts was temporarily restored in the vast majority of MPOA-injured males by the i.p. administration of the ergot derivative, lisuride. About 50% of these MPOA-damaged males even ejaculated, often after a low number of intromissions and short ejaculation latencies. On the other hand, injections of naloxone (an opiate receptor antagonist) failed to activate mounting in MPOA-lesioned or castrated rats. On the basis of these findings the possible ways in which steroid hormone-sensitive brain areas might interact with monoamine-containing pathways are discussed.U
众所周知，内侧视前区（MPOA）和外侧下丘脑区（LHA）的电解损伤会严重损害大鼠的雄性性行为。我们在此报告，向MPOA双侧注入神经毒素鹅膏蕈氨酸（IBO）在消除交配行为方面与电解损伤同样有效，而在LHA进行类似注入后未检测到行为影响。对暴露于IBO后的MPOA和LHA进行组织学检查发现，神经元细胞体广泛退化，几乎没有非特异性损伤的迹象。此外，免疫组织化学研究表明，尽管进行了IBO处理，MPOA的5-羟色胺能神经支配在很大程度上仍保持完整；同样，IBO对LHA中内侧前脑束酪氨酸羟化酶免疫反应性纤维造成的损伤微不足道。这些数据表明：（i）MPOA神经细胞体的功能完整性对于性行为的表达是必要的，以及（ii）LHA电解损伤导致的交配行为中断是由于内侧前脑束纤维系统的中断。对未交配雄性大鼠的行为观察表明，MPOA损伤并未干扰它们与发情雌性大鼠性互动的所有方面；相反，它们似乎特别无法做出通常与骑跨相关的反射性骨盆推顶动作。然而，我们在此报告，通过腹腔注射麦角衍生物利苏瑞，绝大多数MPOA损伤的雄性大鼠暂时恢复了进行带有骨盆推顶动作的骑跨能力。这些MPOA损伤的雄性大鼠中约50%甚至射精，通常在少量插入和较短射精潜伏期后。另一方面，注射纳洛酮（一种阿片受体拮抗剂）未能激活MPOA损伤或阉割大鼠的骑跨行为。基于这些发现，讨论了类固醇激素敏感脑区可能与含单胺途径相互作用的可能方式。
