Surface architecture of the olfactory epithelium of two Chinese cave loaches (Cypriniformes: Nemacheilidae:Oreonectes)

Abstract

The surface of the olfactory epithelium of two species of cave loaches in China, Oreonectes polystigmus and O. guananensis, was studied by scanning electron microscopy (SEM). The structure of the olfactory organ of the two species is quite different from each other; as well, the distribution patterns of cell types in the olfactory epithelium of the studied species showed interesting features. A needle-like spine is visible on the lamellae of the olfactory organ of O. polystigmus, which is a unique character in this species. Ciliated non-sensory cells and microvillus sensory cells showed a different distribution in the two species, being more numerous in O. polystigmus. The non-sensory elements in O. guananensis were ciliated non-sensory cells, with microridges and chloride cells. The presence of chloride cells in the olfactory epithelium of O. guananensis may be of special interest in this species; otherwise, possible differences and physiological changes of the concerned species should be taken into account in order to explain such variability in cell types

Olfactory rod cells: a rare cell type in the larval zebrafish olfactory epithelium with an actin-rich apical projection

“…Previous studies have provided brief descriptions of similar cell types in other teleost species, including the common minnow (Bannister, 1965), several eel species (Schulte, 1972; Yamamoto & Ueda, 1978), goldfish (Breipohl et al, 1973; Ichikawa & Ueda, 1977), rainbow trout (Rhein et al, 1981), common bleak (Hernádi, 1993), catfish (Datta & Bandopadhyay, 1997), and several cave fish and cave loach species (Waryani et al, 2013; Waryani et al, 2015; Zhang et al, 2018).…”

“…More recent reports include comparisons of the surface structures of olfactory epithelia in different adult cave fish and loaches. SEMs in Sinocyclocheilus jii and S. furcodorsalis cave fish, and in Oreonectes polystigmus and O. guananensis cave loaches revealed that olfactory rods were clustered in different regions of olfactory rosette lamellae (Waryani et al, 2013; Waryani et al, 2015). Another SEM study on the variations in olfactory systems of adult cave fish species of different habitats reported not just one, but three different cell types all classified as ‘rod cilia’ in the olfactory epithelia of S. anshuiensis and S. tianlinensis .…”

“…A mechanosensory role for zebrafish olfactory rod cells, for example in detecting ciliary movement or ciliary-driven fluid flow, or a chemosensory role in detecting odorants, could aid olfactory perception in the larva. The olfactory rod cell has previously been referred to as a sensory receptor cell in studies of other teleost species (Bannister, 1965; Schulte, 1972; Breipohl et al, 1973; Waryani et al, 2013; Waryani et al, 2015). Although functions were not explicitly investigated, Bannister (1965) speculated that based on their internal structure, minnow olfactory rod cells perform specific chemosensory roles.…”

Olfactory Rod Cells: A Rare Cell Type in the Larval Zebrafish Olfactory Epithelium With a Large Actin-Rich Apical Projection

“…More recent reports include comparisons of the surface structures of olfactory epithelia in different adult cave fish and loaches. SEMs in Sinocyclocheilus jii and S. furcodorsalis cave fish, and in Oreonectes polystigmus and O. guananensis cave loaches revealed that olfactory rods were clustered in different regions of olfactory rosette lamellae (Waryani et al, 2013(Waryani et al, , 2015. Another SEM study on the variations in olfactory systems of adult cave fish species of different habitats reported not just one, but three different cell types all classified as "rod cilia" in the olfactory epithelia of S. anshuiensis and S. tianlinensis.…”

“…Previous studies have provided descriptions of cell types similar to the olfactory rod cell in other teleost species, including the common minnow (Bannister, 1965), several eel species (Schulte, 1972;Yamamoto and Ueda, 1978), goldfish (Breipohl et al, 1973;Ichikawa and Ueda, 1977), rainbow trout (Rhein et al, 1981), common bleak (Hernádi, 1993), catfish (Datta and Bandopadhyay, 1997), and several cave fish and cave loach species (Waryani et al, 2013(Waryani et al, , 2015Zhang et al, 2018).…”