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. Copyright (C) 2011 S. Karger AG, Basel