Morphology of the paca vomeronasal organ (Cuniculus paca Linnaeus, 1766)

Abstract

The vomeronasal organ is a chemical receptor capable of detecting pheromones and for this reason is involved in reproductive, social and defense behaviors. The breeding of pacas has been highlighted in commercialization of meat and for conservation and research purposes, as an experimental model. Regarding the necessity of detailing the morphology of the secondary olfactory system, the vomeronasal system, the macroscopic anatomy, microscopic anatomy and topography of the vomeronasal organ (OVN) was described. Five adult pacas, from the wild animal Sector at FCAV, Unesp, Jaboticabal, SP were used. After the euthanasia, it was perfused 10% formaldehyde solution by ascendent aorta. The OVN was dissected for topographic and anatomical descriptions. Then, it was included in plastic paraffin. Five micrometres sections were collected and stained with hematoxylin and eosin. The OVN is located on the floor of the nasal cavity in both sides of the base of nasal septum and it was related to the vomer, palatine process of the premaxilar and maxilar bones. In rostral aspect, it has a communication with the oral cavity and with the incisive papilla. It is a paired organ with irregular surface. In transversal section is slight elliptical with brownish colour similar to a sponge full of blood vessels. By light microscopy, it was observed the vomeronasal cartilage. The organ is covered with non-sensorial and neurossensorial epithelia.