A detailed morphological study of the vomeronasal organ and the accessory olfactory bulb of cats.

The organization of the vomeronasal system (VNS) of fetal, newborn, and adult cats was investigated by microdissection and microscopic examination of sections stained conventionally or with lectins (UEA-1, LEA) or antibodies against proteins Gα(i2) (associated with vomeronasal receptor type1) and Gα(o) (associated with receptor vomeronasal receptor type2). The feline VNS is morphologically similar to that of other mammals. Staining with lectins and anti-Gα(i2) was uniform throughout the sensory epithelium of the vomeronasal organ, and throughout the nervous and glomerular layers of the accessory olfactory bulb (AOB); anti-Gα(o) stained no VNS tissue. This organization places the cat together with several other domestic or farm animals (dog, horse, sheep, goat, pig) in a group of mammals with just a single path of communication between the sensory epithelium of the vomeronasal organ and AOB, in contrast to the two-path model found in rodents and other mammals (in which apical and basal sensory epithelium layers project to rostral and caudal AOB areas, respectively). However, the cat differs from the sheep and pig in that the development of its VNS is still incomplete at birth.