果蠅能夠本能地避開二氧化碳,，比如說由緊張的其他果蠅所產(chǎn)生的二氧化碳,，但當(dāng)二氧化碳與其他氣味劑（如由成熟的水果所產(chǎn)生的氣味劑）相結(jié)合時(shí)，它們又能克服這種先天排斥力,。
Stephanie Turner 和Anandasankar Ray報(bào)告說,，這類能夠改變行為的食物氣味劑直接作用于果蠅觸角中對(duì)二氧化碳敏感的神經(jīng)元上，而不是像人們所想的那樣通過其他嗅覺通道間接發(fā)揮作用,。其他天然出現(xiàn)的氣味劑也能阻斷庫(kù)蚊對(duì)二氧化碳有反應(yīng)的神經(jīng)元的作用,。庫(kù)蚊是西尼羅河病毒及絲蟲病的昆蟲媒介。鑒于這些昆蟲能被人呼出的二氧化碳所吸引,，這些抑制蚊子中對(duì)二氧化碳敏感的神經(jīng)元的抑制劑,，有可能幫助尋找通過阻斷這一通道發(fā)揮作用的驅(qū)蚊劑。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 461, 277-281 (10 September 2009) | doi:10.1038/nature08295
Modification of CO2 avoidance behaviour in Drosophila by inhibitory odorants
Stephanie Lynn Turner1 & Anandasankar Ray2
1 Cellular, Molecular, and Developmental Biology Program,
2 Department of Entomology, University of California, Riverside, California 92521, USA
Correspondence to: Anandasankar Ray2 Correspondence and requests for materials should be addressed to A.R.
The fruitfly Drosophila melanogaster exhibits a robust and innate olfactory-based avoidance behaviour to CO2, a component of odour emitted from stressed flies1. Specialized neurons in the antenna and a dedicated neuronal circuit in the higher olfactory system mediate CO2 detection and avoidance1, 2. However, fruitflies need to overcome this avoidance response in some environments that contain CO2 such as ripening fruits and fermenting yeast, which are essential food sources. Very little is known about the molecular and neuronal basis of this unique, context-dependent modification of innate olfactory avoidance behaviour. Here we identify a new class of odorants present in food that directly inhibit CO2-sensitive neurons in the antenna. Using an in vivo expression system we establish that the odorants act on the Gr21a/Gr63a CO2 receptor3. The presence of these odorants significantly and specifically reduces CO2-mediated avoidance behaviour, as well as avoidance mediated by 'Drosophila stress odour'. We propose a model in which behavioural avoidance to CO2 is directly influenced by inhibitory interactions of the novel odours with CO2 receptors. Furthermore, we observe differences in the temporal dynamics of inhibition: the effect of one of these odorants lasts several minutes beyond the initial exposure. Notably, animals that have been briefly pre-exposed to this odorant do not respond to the CO2 avoidance cue even after the odorant is no longer present. We also show that related odorants are effective inhibitors of the CO2 response in Culex mosquitoes that transmit West Nile fever and filariasis. Our findings have broader implications in highlighting the important role of inhibitory odorants in olfactory coding, and in their potential to disrupt CO2-mediated host-seeking behaviour in disease-carrying insects like mosquitoes.
