Neurochemical Features and Glycan Patterns in the Wapiti Vomeronasal Pathway

The vomeronasal system (VNS) plays a central role in mammalian chemical communication, mediating critical social and reproductive behaviors. In the wapiti ( Cervus canadensis ), a cervid species with complex social structures and pronounced chemical signaling during the rut, the VNS had not been previously characterized. This study provides the first comprehensive anatomical and neurochemical analysis of the VNS in wapiti using histological, lectin-histochemical, and immunohistochemical techniques. The vomeronasal organ (VNO) exhibited clear rostrocaudal differentiation, with distinct sensory and respiratory epithelia, a complex glandular distribution, and region-specific expression of neural markers. Lectin binding patterns confirmed functional compartmentalization along the epithelium, and immunoreactivity for markers such as OMP, PGP9.5, CR, and G-protein subunits (Gαi2, Gγ8, and Gα0) revealed detailed molecular organization. Notably, Gα0-positive neurons in the epithelium did not project to the accessory olfactory bulb (AOB), suggesting alternative targets, possibly within transitional zones. The AOB showed all canonical layers, including well-defined glomeruli and expression of markers such as calbindin, CR, GFAP, and LEA lectin. Novel findings include the presence of large white matter tracts and region-specific lectin distribution. Confocal double immunofluorescence and autofluorescence imaging were also employed, allowing high-resolution visualization of neuroepithelial architecture and glomerular domains. Altogether, our results demonstrate that the vomeronasal system in wapiti is highly developed and functionally specialized. These findings contribute to a better understanding of chemosensory communication in wild ungulates and provide a comparative framework for future studies in cervid behavior, reproduction, and conservation.