Morphology and histochemistry of the peripheral olfactory organ in the round goby, Neogobius melanostomus (Teleostei: Gobiidae)

Abstract

This first comprehensive study of the peripheral olfactory organ from a representative of the large and economically important order of teleost fishes, the Perciformes, shows a compact structure with olfactory sensory neurons distributed widely throughout the olfactory chamber. The spatial organization of the nasal cavity in the bottom-dwelling round goby (Gobiidae, Neogobius melanostomus) was examined using impression material injection, immunocytochemistry, and transmission electron microscopy. The olfactory chamber contains a single olfactory lamella; prominent dorsocaudal lachrymal and ethmoidal accessory nasal sacs are situated ventrocaudal to the chamber. The location of the olfactory mucosa within the olfactory chamber is novel for teleost fish, as it extends beyond the ventral surface to the lateral and dorsal regions. Microvillar olfactory sensory neurons and ciliated olfactory sensory neurons were identified by transmission electron microscopy and the spatial distribution of these two cell types was assessed through immunocytochemistry against olfactory receptor coupled G-proteins. Both G(alphaolf)-immunoreactive ciliated olfactory sensory neurons and the G(alphao)-immunoreactive microvillar form were located throughout the olfactory epithelium. Ciliated crypt cells were G(alphao) immunoreactive and were found throughout the olfactory epithelium of some specimens. The widespread occurrence of olfactory sensory neurons in the olfactory chamber supports the idea that olfactory signaling is important to the survival of the round goby. The prominence of the lachrymal and ethmoidal accessory nasal sacs indicates the capacity to regulate the flow of odorant molecules over the sensory surface of the olfactory sensory neurons, possibly through a pump-like mechanism driven by opercular activity associated with gill ventilation.

Hydrodynamic aspects of fish olfaction

“…1 distance over which an odorant must travel to reach the olfactory epithelium is less (figure 6). It should also be noted that even olfactory chambers that lack welldefined lamellae, such as those of the striped panchax (Zeiske 1974) and the round goby (Neogobius melanostomus; Belanger et al 2003), could be regarded as a single pair of parallel plates, albeit a convoluted one (e.g. Zeiske 1974, fig.…”

“…The olfactory chamber of this organ, which lacks any form of lamellar array, is lined with kinociliated cells. Intriguingly, the organ also possesses two accessory sacs (Belanger et al 2003), raising the possibility that it is ventilated by both the beating of cilia and the pumping action of these sacs (there is precedent for such a combined mechanism in the olfactory organ of the juvenile Macculloch's rainbowfish, Melanotaenia maccullochi; Breucker et al 1979, p. 65). Whether these sacs are capable of pumping water through the chamber in a unidirectional fashion rests upon the presence of a valve.…”

Appearance of Crypt Neurons in the Olfactory Epithelium of the Skate Raja clavata During Development

“…men to specimen and from season to season, suggesting a certain variability and feedback control of the expression of the CN population (Belanger et al, 2003;Hamdani and Døving, 2006).…”

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

“…On the other hand, since putative pheromones are identified in some fish species [14,15], the olfactory function of the VNO may be taken charge of by the OE in fish. This presumption may be approved by the presence of three kinds of olfactory receptor cells (ORC) in the fish OE, that is, ciliated cells, microvillous cells and crypt cells [1,3,18]. 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].…”

“…This presumption may be approved by the presence of three kinds of olfactory receptor cells (ORC) in the fish OE, that is, ciliated cells, microvillous cells and crypt cells [1,3,18]. 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.…”