Fine structure of three types of olfactory organs inXenopus laevis

Abstract

There is no report on the fine structure of three types of olfactory organs in Xenopus laevis. Their functional assignments in olfaction are not yet established. The fine structure of three types of olfactory organs, olfactory epithelium (OE), vomeronasal organ (VNO), and middle chamber epithelium (MCE), was examined in Xenopus laevis by light and electron microscopy. The olfactory cells of the OE and the sensory cells of the VNO were equipped with cilia and microvilli, respectively, similar to terrestrial animals that possess both the OE and the VNO. On the other hand, the sensory cells of the MCE were classified into two types, the sensory cells with cilia and the sensory cells with microvilli, like those of the OE in fish. These findings suggest that the OE and the VNO in Xenopus laevis detect different kinds of odoriferous molecules in air, whereas the MCE is involved in the perception of odorants in water.

Expression Patterns of Glycoconjugates in the Three Distinctive Olfactory Pathways of the Clawed Frog, Xenopus laevis.

“…Morphological characteristics between the olfactory epithelium and the middle chamber epithelium are also different. The olfactory epithelium contains ciliated receptor neurons, whereas the middle chamber epithelium contains both ciliated and microvillous receptor neurons [16,27]. Although the functional significance of the vomeronasal epithelium in amphibians remains unclear, these previous studies strongly suggest the presence of three types of distinct olfactory subsystems in the Xenopus primary olfactory system.…”

Embryonic and Postnatal Differentiation of Olfactory Epithelium and Vomeronasal Organ in the Syrian Hamster

“…Fine structure of the olfactory epithelium (OE) and vomeronasal organ (VNO) has been well-documented on various species of amphibians [6,9,17,[19][20][21], reptiles [10,18] and mammals [1,3,[14][15][16]. Details in their developmental changes have also been well-documented in various species [4,7,8,19,[23][24][25][26].…”

Differential Expression of Histochemical Characteristics in the Developing Olfactory Receptor Cells in a Flatfish, Barfin Flounder (<i>Verasper moseri</i>)

“…Ciliated and microvillous cells are strongly supposed to differ in the property of odorant perception from each other by histochemical and electrophysiological studies [1,7,8,11]. Since the ORC of the OE are ciliated and the ORC of the VNO are microvillous in general in the tetrapod [9], the general odorants may be perceived by the ciliated ORC and pheromonal molecules by the microvillous ORC in fish. In addition, crypt cells are unique olfactory neurons, and their olfactory function remains obscure [3].…”