Supplementary Material for: Chemo- and Thermosensory Responsiveness of Grueneberg Ganglion Neurons Relies on Cyclic Guanosine Monophosphate Signaling Elements

Neurons of the Grueneberg ganglion (GG) in the anterior nasal region of mouse pups respond to cool temperatures and to a small set of odorants. While the thermosensory reactivity appears to be mediated by elements of a cyclic guanosine monophosphate (cGMP) cascade, the molecular mechanisms underlying the odor-induced responses are unclear. Since odor-responsive GG cells are endowed with elements of a cGMP pathway, specifically the transmembrane guanylyl cyclase subtype GC-G and the cyclic nucleotide-gated ion channel CNGA3, the possibility was explored whether these cGMP signaling elements may also be involved in chemosensory GG responses. Experiments with transgenic mice deficient for GC-G or CNGA3 revealed that GG responsiveness to given odorants was significantly diminished in these knockout animals. These findings suggest that a cGMP cascade may be important for both olfactory and thermosensory signaling in the GG. However, in contrast to the thermosensory reactivity, which did not decline over time, the chemosensory response underwent adaptation upon extended stimulation, suggesting that the two transduction processes only partially overlap.

格鲁内贝格神经节（Grueneberg ganglion, GG）是幼鼠鼻前区的神经结构，其神经元可对低温环境及少量气味物质产生应答。该神经元的温度感知反应似乎由环磷酸鸟苷（cyclic guanosine monophosphate, cGMP）级联反应的相关组分介导，但气味诱导应答的分子机制尚未明确。由于对气味敏感的GG细胞具备cGMP信号通路的相关组分，具体为跨膜鸟苷酸环化酶亚型GC-G与环核苷酸门控离子通道CNGA3，研究人员据此探究了这些cGMP信号组分是否同样参与了GG细胞的化学感受应答。针对GC-G或CNGA3基因敲除的转基因小鼠开展的实验显示，在上述敲除动物体内，GG细胞对特定气味物质的应答能力显著降低。上述结果表明，cGMP级联反应可能在GG细胞的嗅觉与温度感知信号转导过程中均发挥关键作用。不过，与随时间推移无明显衰减的温度感知反应不同，化学感受应答在持续刺激后会出现适应现象，这提示两种信号转导过程仅存在部分重叠。