Histological Studies Of The Vomeronasal Organ Of African Giant Rat (Cricetomys gambianus, Waterhouse)

Abstract

The vomeronasal organ (VNO), a chemoreceptive organ was studied in African giant rat (Cricetomys gambianus, Waterhouse), a macrosmatic animal, by means of gross dissection and light microscopy. The VNO was located in the rostral part of the base of the nasal septum. It was tubular in shape, about 10.6 mm in length and opened in the rostral region of the nasal cavity, with a blind caudal end that terminated in glandular branches. Its lumen in the middle segment was lined by sensory epithelium on the medial wall and non-sensory epithelium on the lateral wall. The sensory epithelium showed sensory, supporting and basal cells, whereas the non-sensory wall contained psendostratified columnar cells with ciliated epithelium. Vomeronasal glands were present in the lateral wall and on the dorso-lateral region between the sensory and non-sensory epithel a. Intraepithelial blood vessels were observed on the medial sensory epithelium. Nerve bundles were also apparent in the medial sensory wall. The vomeronasal capsule incompletely housed the organ and showed ossified areas. The histological observations suggest that the VNO is an important organ in sexual behaviours as in other rodents and will throw more light on future studies of the vomeronasal organ.

Comparative morpho-histological analysis on the vomeronasal organ and the accessory olfactory bulb in Balady dogs (Canis familiaris) and New Zealand rabbits (Oryctolagus cuniculus)

“…It was 15 mm in cats [34]. However, sheep and goats had a bodyweight resembling that of dogs, but the length of the organ was 6–8 cm in goat [30], 6–9 cm in Iraqi sheep [31], and 10.6 mm in African giant rat [35]. The vomeronasal organ of rodents [16] and rabbit [36,37] opened in the nasal cavity and indirectly connecting with the oral cavity by the nasopalatine duct, whereas in carnivores [13,34], goat [30], and bears [38], the organ united with the nasopalatine duct and had a direct connection with the oral cavity.…”

“…Also, we found areas of stratified squamous near the dorsal end of the duct in rabbits and the caudal part of the organ of the dog had only the SE. In addition, in rats [35] and cats [34], four kinds of epithelium were recognized in the VD; the epithelium became simple columnar caudally and stratified squamous cranially. In contrast, the blind mole rats had only one type of epithelium; the sensory one [45].…”