The Grueneberg ganglion of the mouse projects axons to glomeruli in the olfactory bulb

Abstract

First described in 1973, the Grueneberg ganglion (GG) is an arrow-shaped neuronal structure at the anterior end of the nasal cavity. It lines both sides of the nasal septum, within the nasal vestibule, close to the opening of the naris. The functions of the GG and the pattern of projections to the brain are not known. Here, we report that neurons of the mouse GG express olfactory marker protein, which is normally expressed in mature olfactory or vomeronasal sensory neurons. The approx. 500 cells in each GG are arranged in several densely packed cell clusters. Individual cells give rise to single axons, which fasciculate to form a nerve bundle that projects caudally. The axons terminate in glomeruli of the olfactory bulb, one or two large glomeruli associated with a semicircle of up to 10 smaller, somewhat diffusely organized glomeruli that surround the most anterior part of the accessory olfactory bulb. Development of the GG starts around embryonic day 16 and appears to be completed at birth; cell numbers then undergo a minor decrease during postnatal development. The strategic location of the GG, expression of olfactory marker protein, axonal projections to glomeruli at particular locations in the olfactory bulb and early development suggest that this neuronal structure performs specific chemosensory functions at neonatal stages.

Axonal wiring of guanylate cyclase-D-expressing olfactory neurons is dependent on neuropilin 2 and semaphorin 3F

“…Several markers distinguishes these neurons from OR-expressing OSNs or VR-expressing VSNs: placental antigen X-P2 (Shinoda et al, 1989;Shinoda et al, 1993), antigens to antibodies 2C6 and mAb213 (Ring et al, 1997), and guanylate cyclase-D (GC-D) (Fülle et al, 1995;Juilfs et al, 1997). Neurons from the Grueneberg ganglion also project to the necklace area (Fuss et al, 2005). Thus, the necklace area is heterogeneous in axonal input.…”

“…The specific function of the septal organ has not been established; its neurons may also have mechanosensory abilities (Grosmaitre et al, 2007). Second, the Grueneberg ganglion, located at the tip of the nose (Grueneberg, 1973), is now regarded as an olfactory subsystem (Fuss et al, 2005;Koos and Fraser, 2005;Fleischer et al, 2006;Roppolo et al, 2006). Its function is not known.…”

Grueneberg Ganglion Neurons Are Finely Tuned Cold Sensors

“…It consists of a cluster of neurons-henceforward referred to as Grueneberg ganglion neurons (GGNs)-that express olfactory marker protein (OMP) and project their axons to a small number of glomeruli in the caudal main olfactory bulb (Fuss et al, 2005;Koos and Fraser, 2005;Fleischer et al, 2006;Roppolo et al, 2006;Storan and Key, 2006). Interestingly, these glomeruli are near the necklace glomeruli innervated by olfactory sensory neurons expressing the receptor guanylyl cyclase GC-D (Fülle et al, 1995;Juilfs et al, 1997;Leinders-Zufall et al, 2007;Walz et al, 2007; for review, see Munger et al, 2009), and both GC-D-expressing neurons and GGNs express elements of a cGMP second messenger pathway, including the cGMP-specific cyclic nucleotide-gated channel CNGA3 and the cGMP-stimulated phosphodiesterase PDE2 (Juilfs et al, 1997;Meyer et al, 2000;Leinders-Zufall et al, 2007;Fleischer et al, 2009;Liu et al, 2009).…”

Mouse alarm pheromone shares structural similarity with predator scents

“…The GG displays multimodal properties (21,(30)(31)(32)(33) and starts developing around embryonic day 16. Contrary to the other olfactory subsystems, the GG appears to be complete and functional at birth (24)(25)(26)(27)(28), ensuring immediate AP sensing and increasing chances of survival in the wild. An intact GG is necessary to observe the fearful behavior of the recipient animals in the presence of APs (21).…”