UMR 1272, UPMC-INRA, Physiologie de l'Insecte: Signalisation et Communication, Université Paris VI, Bâtiment A, 7 quai Saint Bernard, 75005 Paris, France.
Gen Comp Endocrinol. 2013 Jun 1;186:58-66. doi: 10.1016/j.ygcen.2013.02.024. Epub 2013 Mar 5.
In most animals, including insects, male reproduction depends on the detection and processing of female-produced sex pheromones. In the male moth, Agrotis ipsilon, both behavioral response and neuronal sensitivity in the primary olfactory center, the antennal lobe (AL), to female sex pheromone are age- and hormone-dependent. In many animal species, steroids are known to act at the brain level to modulate the responsiveness to sexually relevant chemical cues. We aimed to address the hypothesis that the steroidal system and in particular 20-hydroxyecdysone (20E), the main insect steroid hormone, might also be involved in this olfactory plasticity. Therefore, we first cloned the nuclear ecdysteroid receptor EcR (AipsEcR) and its partner Ultraspiracle (AipsUSP) of A. ipsilon, the expression of which increased concomitantly with age in ALs. Injection of 20E into young sexually immature males led to an increase in both responsiveness to sex pheromone and amount of AipsEcR and AipsUSP in their ALs. Conversely, the behavioral response decreased in older, sexually mature males after injection of cucurbitacin B (CurB), an antagonist of the 20E/EcR/USP complex. Also, the amount of AipsEcR and AipsUSP significantly declined after treatment with CurB. These results suggest that 20E is involved in the expression of sexual behavior via the EcR/USP signaling pathway, probably acting on central pheromone processing in A. ipsilon.
在大多数动物中，包括昆虫，雄性繁殖依赖于对雌性产生的性信息素的检测和处理。在雄性夜蛾 Agrotis ipsilon 中，对雌性性信息素的行为反应和初级嗅觉中枢——触角叶（AL）中的神经元敏感性都依赖于年龄和激素。在许多动物物种中，类固醇已知在大脑水平上起作用，以调节对性相关化学线索的反应性。我们旨在验证以下假设：甾体系统，特别是昆虫主要类固醇激素 20-羟基蜕皮酮（20E），也可能参与这种嗅觉可塑性。因此，我们首先克隆了 A. ipsilon 的核蜕皮激素受体 EcR（AipsEcR）及其伴侣 Ultraspiracle（AipsUSP），其在 AL 中的表达随年龄的增长而增加。将 20E 注射到年轻的未成熟雄性中，会导致其对性信息素的反应性以及 AL 中的 AipsEcR 和 AipsUSP 的数量增加。相反，在注射 20E 拮抗剂瓜瓜他丁 B（CurB）后，年龄较大的性成熟雄性的行为反应下降。此外，CurB 处理后 AipsEcR 和 AipsUSP 的数量也显著下降。这些结果表明，20E 通过 EcR/USP 信号通路参与性行为的表达，可能作用于 A. ipsilon 的中央信息素处理。
