Many insects can detect carbon dioxide (CO₂) plumes using a conserved receptor made up of members of the gustatory receptor (Gr) family Gr1, Gr2 and Gr3. Mosquitoes are attracted to host animals for blood meals using plumes of CO₂ in the exhaled breath using the receptor expressed in the A neuron of the capitate peg sensilla type on the maxillary palps. The receptor is known to also detect several other classes of odorants, including ones emitted from human skin. Here, we discover that a common skin odorant, butyric acid, can cause a phasic activation followed by an unusually prolonged tonic activity after the stimulus is over in the CO₂ neurons of mosquitoes. The effect is conserved in both Aedes aegypti and Anopheles gambiae mosquitoes. This raises a question about its role in a mosquito's preference for the skin odour of different individuals. Butyric acid belongs to a small number of odorants known to cause the prolonged activation of the CO₂ receptor. A chemical informatic analysis identifies a specific set of physico-chemical features that can be used in a machine learning predictive model for the prolonged activators. Interestingly, this set is different from physico-chemical features selected for activators or inhibitors, indicating that each has a distinct structural basis. The structural understanding opens up an opportunity to find novel ligands to manipulate the CO₂ receptor and mosquito behaviour.

许多昆虫可以使用由味觉受体 (Gr) 家族 Gr1、Gr2 和 Gr3 的成员组成的保守受体来检测二氧化碳 (CO _{2 ) 羽流。}使用在上颌触须上的头状钉感器类型的 A 神经元中表达的受体，使用呼出气中的 CO ₂羽流将蚊子吸引到宿主动物身上进行血食。已知该受体还可以检测其他几类气味，包括从人体皮肤发出的气味。在这里，我们发现一种常见的皮肤气味剂丁酸可以引起阶段性激活，然后在蚊子的 CO ₂神经元中刺激结束后会出现异常延长的强直活动。这种效应在埃及伊蚊和冈比亚按蚊。这就提出了一个问题，即它在蚊子对不同个体皮肤气味的偏好中所起的作用。丁酸属于少数已知会导致CO ₂受体长期活化的气味剂。化学信息分析确定了一组特定的物理化学特征，可用于机器学习预测模型中的延长激活剂。有趣的是，这组与为激活剂或抑制剂选择的物理化学特征不同，表明每个都有不同的结构基础。对结构的理解为寻找新的配体来操纵CO ₂受体和蚊子行为提供了机会。