Jackson L M, Harder J D
Department of Zoology, Ohio State University, Columbus 43210, USA.
Biol Reprod. 1996 Feb;54(2):506-12. doi: 10.1095/biolreprod54.2.506.
Estrus is induced in female gray short-tailed opossums (Monodelphis domestica) by exposure to male chemical signals (pheromones). Isolated females remain anestrous, but direct exposure to a male or his scent-marked cage induces estrus within 4-6 days. The objective of this study was to investigate the importance of the vomeronasal organ in detection of and response to estrus-inducing pheromones. The vomeronasal organ was surgically removed through the palate from 8 females (VNX); 5 females (SHAM) underwent sham surgeries in which the vomeronasal organ was exposed but not removed. After a 10-day recovery period, females were placed into male scent-marked cages. Body weight and urogenital sinus cytology were monitored throughout the experiment. All females were anesthetized and perfused with 4% paraformaldehyde 12-13 days after initial pheromone exposure. Vomeronasal organ ablation was evaluated histologically in decalcified snouts. In addition, deafferentation of the accessory olfactory bulb was confirmed by use of a lectin stain specific for the vomeronasal nerve and the glomerular layer of the bulb. All females classified as completely VNX (n = 5) remained anestrous throughout the pheromonal exposure. Incompletely VNX females (n = 2) and all SHAM animals exhibited estrus within 7 days of pheromone stimulation. At perfusion, the mean uterine weight (280.71 +/- 95.6 mg/85 g BW) of SHAM females was greater (p < 0.05) than that of unresponsive, VNX females (133.33 +/- 31.14 mg/85 g). This study demonstrates that the vomeronasal organ is an essential component for transduction of male pheromones required for induction of estrus in a marsupial species.
通过暴露于雄性化学信号（信息素）可诱导雌性灰短尾负鼠（Monodelphis domestica）进入发情期。单独饲养的雌性负鼠处于静止发情期，但直接接触雄性或其有气味标记的笼子会在4 - 6天内诱导发情。本研究的目的是调查犁鼻器在检测和响应诱导发情的信息素中的重要性。通过腭部手术从8只雌性负鼠（VNX组）中摘除犁鼻器；5只雌性负鼠（假手术组，SHAM）接受假手术，即暴露犁鼻器但不摘除。经过10天的恢复期后，将雌性负鼠放入有雄性气味标记的笼子里。在整个实验过程中监测体重和泌尿生殖窦细胞学变化。在初次接触信息素12 - 13天后，所有雌性负鼠均被麻醉并用4%多聚甲醛灌注。在脱钙的口鼻部对犁鼻器切除情况进行组织学评估。此外，通过使用针对犁鼻神经和嗅球肾小球层的凝集素染色来确认副嗅球的传入神经切断。所有被归类为完全切除犁鼻器的雌性负鼠（n = 5）在整个信息素暴露期间均处于静止发情期。未完全切除犁鼻器的雌性负鼠（n = 2）和所有假手术组动物在信息素刺激后7天内出现发情。在灌注时，假手术组雌性负鼠的平均子宫重量（280.71 +/- 95.6 mg/85 g体重）高于无反应的切除犁鼻器组雌性负鼠（133.33 +/- 31.14 mg/85 g）（p < 0.05）。本研究表明，犁鼻器是有袋类动物诱导发情所需的雄性信息素转导的重要组成部分。
