爱让嗅觉失灵

爱让嗅觉失灵：交配行为能通过Or65a嗅觉神经元使雌果蝇免受信息素吸引

报道：爱不仅能蒙蔽双眼，还能蒙蔽嗅觉！最近，瑞典农业科学大学的Sébastien Lebreton博士及其团队发现，嗅觉受体Or65a能使刚刚交配完的雌性果蝇不再受到来自雄果蝇的性信息素吸引，从而调节雌果蝇的交配行为。该研究成果发表在最新一期2014年11月19日的Scientific Reports杂志上。

中文翻译

【题目】爱让嗅觉失灵：交配通过Or65a嗅觉神经元使雌性果蝇免受信息素吸引

【译文】通过作用于嗅觉受体Or67d，性信息素cVA能引发雄性果蝇的攻击和求偶行为；雄果蝇若长期持续接触cVA，cVA又会通过另一个嗅觉受体Or65a抑制其求偶行为。而在雌性果蝇身上，我们尚不知道Or65a受体扮演着什么样的角色。本研究发现：交配刚刚完成时，雌果蝇就不再被cVA所吸引，因为嗅觉感受神经元（OSNs）会表达Or65a受体；如果抑制Or65a受体的表达，交配后的雌果蝇仍然会被cVA吸引。表达Or67d受体的神经元汇集于触角叶的DA1神经纤维球，在那里它们的突触连接到投射神经元（PNs）上，由此连接到高级神经回路，令高级神经回路控制雌果蝇应答cVA。对投射神经元进行功能成像，可以发现，当嗅觉感受神经元表达Or65a受体时，DA1神经纤维球就会被抑制，从而导致雌果蝇对cVA的应答受到抑制。饥饿的雄果蝇产生的cVA较少，与这样的雄果蝇交配，则不会改变雌果蝇对cVA的应答，这表明交配后接触cVA会影响雌果蝇的行为。另外，未交配的雌果蝇如果接触到合成cVA，受到的吸引会减少，性接受度也会降低。综上所述，Or65a受体能引发对cVA的排斥，并通过同时调节雌雄果蝇的行为来规避重复交配。

英文原稿

[Title] Love makes smell blind: mating suppresses pheromone attraction in Drosophila females via Or65a olfactory neurons

[Author] Sébastien Lebreton, Veit Grabe, Aman B. Omondi, Rickard Ignell, Paul G. Becher, Bill S. Hansson, Silke Sachse, & Peter Witzgall

[Abstract] In Drosophila, the male sex pheromone cis-vaccenyl acetate (cVA) elicits aggregation and courtship, through the odorant receptor Or67d. Long-lasting exposure to cVA suppresses male courtship, via a second channel, Or65a. In females, the role of Or65a has not been studied. We show that, shortly after mating, Drosophila females are no longer attracted to cVA and that activation of olfactory sensory neurons (OSNs) expressing Or65a generates this behavioral switch: when silencing Or65a, mated females remain  to cVA. Neurons expressing Or67d converge into the DA1 glomerulus in the antennal lobe, where they synapse onto projection neurons (PNs), that connect to higher neural circuits generating the attraction response to cVA. Functional imaging of these PNs shows that the DA1 glomerulus is inhibited by simultaneous activation of Or65a OSNs, which leads to a suppression of the attraction response to cVA. The behavioral role of postmating cVA exposure is substantiated by the observation that matings with starved males, which produce less cVA, do not alter the female response. Moreover, exposure to synthetic cVA abolishes attraction and decreases sexual receptivity in unmated females. Taken together, Or65a mediates an aversive effect of cVA and may accordingly regulate remating, through concurrent behavioral modulation in males and females.

原文地址：http://www.nature.com/srep/2014/141119/srep07119/full/srep07119.html