Mamasuew Katharina, Hofmann Nina, Kretzschmann Verena, Biel Martin, Yang Ruey-Bing, Breer Heinz, Fleischer Joerg
Institute of Physiology, University of Hohenheim, Stuttgart, Germany.
Neurosignals. 2011;19(4):198-209. doi: 10.1159/000329333. Epub 2011 Aug 31.
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.
幼鼠鼻前部的格伦贝格神经节（GG）中的神经元对低温和一小部分气味剂有反应。虽然热感觉反应似乎是由环磷酸鸟苷（cGMP）级联的成分介导的，但气味诱导反应的分子机制尚不清楚。由于对气味有反应的GG细胞具有cGMP途径的成分，特别是跨膜鸟苷酸环化酶亚型GC-G和环核苷酸门控离子通道CNGA3，因此探讨了这些cGMP信号成分是否也可能参与GG的化学感觉反应。对缺乏GC-G或CNGA3的转基因小鼠进行的实验表明，在这些基因敲除动物中，GG对特定气味剂的反应性显著降低。这些发现表明，cGMP级联可能对GG中的嗅觉和热感觉信号传导都很重要。然而，与不随时间下降的热感觉反应不同，化学感觉反应在长时间刺激后会发生适应，这表明这两种转导过程仅部分重叠。
