Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Science. 2013 Jun 14;340(6138):1334-8. doi: 10.1126/science.1234133.
Below a certain level, table salt (NaCl) is beneficial for animals, whereas excessive salt is harmful. However, it remains unclear how low- and high-salt taste perceptions are differentially encoded. We identified a salt-taste coding mechanism in Drosophila melanogaster. Flies use distinct types of gustatory receptor neurons (GRNs) to respond to different concentrations of salt. We demonstrated that a member of the newly discovered ionotropic glutamate receptor (IR) family, IR76b, functioned in the detection of low salt and was a Na(+) channel. The loss of IR76b selectively impaired the attractive pathway, leaving salt-aversive GRNs unaffected. Consequently, low salt became aversive. Our work demonstrated that the opposing behavioral responses to low and high salt were determined largely by an elegant bimodal switch system operating in GRNs.
在一定水平以下，食盐（NaCl）对动物有益，而过量的盐则有害。然而，低盐和高盐味觉感知如何被不同地编码仍不清楚。我们在黑腹果蝇中鉴定了一种盐味觉编码机制。果蝇使用不同类型的味觉受体神经元（GRNs）来响应不同浓度的盐。我们证明，新发现的离子型谷氨酸受体（IR）家族的一个成员 IR76b 在检测低盐时起作用，并且是一种 Na+通道。IR76b 的缺失选择性地损害了吸引力途径，而不影响盐厌恶的 GRNs。因此，低盐变得厌恶。我们的工作表明，对低盐和高盐的相反行为反应主要由 GRNs 中运行的一个优雅的双模态开关系统决定。
