Novel Microglomerular Structures in the Olfactory Bulb of Mice

Lipscomb, Brian W.; Treloar, Helen B.; Greer, Charles A.

doi:10.1523/jneurosci.22-03-00766.2002

Cited by 13 publications

(13 citation statements)

References 59 publications

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“…In addition, many GFP-positive glomeruli were seen in anterior-medial and posterior-lateral areas of the bulb. There were 520 Ϯ 149 GFP-positive glomeruli (mean Ϯ SD, n ϭ 6, range 353-750, corrected for oversampling) with an average diameter of 94 Ϯ 5 m. We found that TRPM5-expressing OSNs targeted both regular and microglomeruli (31). These results demonstrate that TRPM5-expressing OSNs preferentially project discreet areas of the bulb, consistent with the zonal expression of TRPM5 in the MOE.…”

Section: Gfp Expressionsupporting

confidence: 70%

Olfactory neurons expressing transient receptor potential channel M5 (TRPM5) are involved in sensing semiochemicals

Lin

Margolskee

Donnert

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

152

157

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Olfactory sensory neurons (OSNs) in the main olfactory epithelium respond to environmental odorants. Recent studies reveal that these OSNs also respond to semiochemicals such as pheromones and that main olfactory input modulates animal reproduction, but the transduction mechanism for these chemosignals is not fully understood. Previously, we determined that responses to putative pheromones in the main olfactory system were reduced but not eliminated in mice defective for the canonical cAMP transduction pathway, and we suggested, on the basis of pharmacology, an involvement of phospholipase C. In the present study, we find that a downstream signaling component of the phospholipase C pathway, the transient receptor potential channel M5 (TRPM5), is coexpressed with the cyclic nucleotide-gated channel subunit A2 in a subset of mature OSNs. These neurons project axons primarily to the ventral olfactory bulb, where information from urine and other socially relevant signals is processed. We find that these chemosignals activate a subset of glomeruli targeted by TRPM5-expressing OSNs. Our data indicate that TRPM5-expressing OSNs that project axons to glomeruli in the ventral area of the main olfactory bulb are involved in processing of information from semiochemicals.signal transduction ͉ pheromone ͉ stimulated emission depletion (STED) microscopy T he olfactory system perceives not only odorants that convey information on the environment but also semiochemicals (chemicals involved in animal communication, from the Greek semeion for ''sign''), including pheromones (1-4). A key step in transmission of information is activation of the canonical cAMP signaling pathway by binding of odorants to olfactory receptors, resulting in influx of Ca 2ϩ through a cyclic nucleotide-gated (CNG) channel and subsequent depolarization (5, 6). Targeted disruption of elements of the cAMP pathway, including the CNG channel subunit A2 (CNGA2) (7), the G protein G olf (8), or adenylyl cyclase (AC) III (9), result in severe deficit of odorantevoked responses to many odorants, demonstrating the dominant role of the cAMP pathway.Semiochemicals, such as pheromones, social attractants, and major histocompatibility complex (MHC)-related odorants, signal social and sexual status, genetic makeup, and species identity important for the survival of the individual and the species (1, 10-13). Recent studies indicate that both the main olfactory epithelium (MOE) and olfactory bulbs respond to these chemosignals (14, 15). Consistent with these findings, sensory information from the main olfactory bulb projects to areas in the hypothalamus housing neurons that produce gonadotropinreleasing hormone and plays an important role in reproduction (16,17). Further, a class of chemosensory receptors that recognize social amines found in urine have been identified recently in the MOE (18). Thus, it now is clear that the main olfactory system is involved in detection of semiochemicals and that the cAMP signaling pathway plays an important role in signal transduction f...

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Section: Gfp Expressionsupporting

confidence: 70%

Olfactory neurons expressing transient receptor potential channel M5 (TRPM5) are involved in sensing semiochemicals

Lin

Margolskee

Donnert

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

152

157

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“…This fits with the (stronger) Slit1 and (weaker) Slit3 RNA expression at its anterior border, possibly in so-called necklace glomeruli (Lipscomb et al, 2002;Shinoda et al, 1989). The actual contribution of Slit1 and Slit3 to this differential expression can not be revealed by this staining method and might require suitable antibodies (Rajagopalan et al, 2000;Simpson et al, 2000).…”

Section: Robo and Slit Expression Patternsmentioning

confidence: 60%

On the topographic targeting of basal vomeronasal axons through Slit-mediated chemorepulsion

et al. 2003

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The vomeronasal projection conveys information provided by pheromones and detected by neurones in the vomeronasal organ (VNO) to the accessory olfactory bulb (AOB) and thence to other regions of the brain such as the amygdala. The VNO-AOB projection is topographically organised such that axons from apical and basal parts of the VNO terminate in the anterior and posterior AOB respectively. We provide evidence that the Slit family of axon guidance molecules and their Robo receptors contribute to the topographic targeting of basal vomeronasal axons. Robo receptor expression is confined largely to basal VNO axons, while Slits are differentially expressed in the AOB with a higher concentration in the anterior part, which basal axons do not invade. Immunohistochemistry using a Robo-specific antibody reveals a zone-specific targeting of VNO axons in the AOB well before cell bodies of these neurones in the VNO acquire their final zonal position. In vitro assays show that Slit1-Slit3 chemorepel VNO axons, suggesting that basal axons are guided to the posterior AOB due to chemorepulsive activity of Slits in the anterior AOB. These data in combination with recently obtained other data suggest a model for the topographic targeting in the vomeronasal projection where ephrin-As and neuropilins guide apical VNO axons, while Robo/Slit interactions are important components in the targeting of basal VNO axons.

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“…2A, blue arrows compared with orange arrow for a single glomerulus). In some bulbs of MOR28-IRES-gap-GFP mice, further divergence is seen by a small subset of axons that project still further from the region of convergence and form what appear to be microglomeruli (26); these structures are outside the scope of this study ( Fig. 2A, red arrow, and Fig.…”

Section: Resultsmentioning

confidence: 79%

“…The lateral MOR28 glomerular domain has a dorsoventral extent of at least 1.4 mm and an anterior-posterior extent of at least 0.4 mm. Some microglomerular structures (26) were present and are pictured (Fig. 2 A, G, I, and H), but they were not included in this study.…”

Section: Resultsmentioning

confidence: 99%

Multiplex assessment of the positions of odorant receptor-specific glomeruli in the mouse olfactory bulb by serial two-photon tomography

Zapiec

Mombaerts

2015

Proc. Natl. Acad. Sci. U.S.A.

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In the mouse, axons of olfactory sensory neurons (OSNs) that express the same odorant receptor (OR) gene coalesce into one or a few glomeruli in the olfactory bulb. The positions of OR-specific glomeruli are traditionally described as stereotyped. Here, we have assessed quantitatively the positions of OR-specific glomeruli using serial two-photon tomography, an automated method for wholeorgan fluorescence imaging that integrates two-photon microscopy with serial microtome sectioning. Our strategy is multiplexed. By repeated crossing, we generated two strains of mice with genetargeted mutations at four or five OR loci for a total of six ORs: MOR23 (Olfr16), mOR37A (Olfr155), M72 (Olfr160), P2 (Olfr17), MOR256-17 (Olfr15), and MOR28 (Olfr1507). Glomerular imaging relied on intrinsic fluorescence of GFP or DsRed, or on wholemount immunofluorescence with antibodies against GFP, DsRed, or β-gal using the method of immunolabeling-enabled threedimensional imaging of solvent-cleared organs (iDISCO). The highresolution 3D-reconstructed datasets were segmented to identify the labeled glomeruli and to assess glomerular positional variability between the bulbs of one mouse (intraindividual) and among the bulbs of different mice (interindividual). In 26 mice aged 21 or 50 d or 10 wk, we made measurements of the positions of 352 glomeruli. We find that positional variability of glomeruli correlates with the OR: For instance, the medial MOR28 glomerular domain occupies a surface area that is an order of magnitude larger than the surface area of the medial MOR23 glomerular domain. Our results quantify the level of precision that is delivered by the mechanisms of OSN axon wiring, differentially for the various OSN populations expressing distinct OR genes.olfaction | glomerulus | gene targeting | axon guidance | olfactory sensory neuron

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Novel Microglomerular Structures in the Olfactory Bulb of Mice

Cited by 13 publications

References 59 publications

Olfactory neurons expressing transient receptor potential channel M5 (TRPM5) are involved in sensing semiochemicals

Olfactory neurons expressing transient receptor potential channel M5 (TRPM5) are involved in sensing semiochemicals

On the topographic targeting of basal vomeronasal axons through Slit-mediated chemorepulsion

Multiplex assessment of the positions of odorant receptor-specific glomeruli in the mouse olfactory bulb by serial two-photon tomography

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