Cytochemical features of olfactory receptor cells in benthic and pelagic Sculpins (Cottoidei) from Lake Baikal

Abstract

Electron and laser confocal microscopy were used to analyze the adaptive cytochemical features of the olfactory epithelium in three genetically close deep-water Cottoidei species endemic to Lake Baikal ? golomyanka (Baikal oilfish) Comephorus baicalensis, longfin Baikal sculpin Cottocomephorus inermis and fat sculpin Batrachocottus nikolskii ? whose foraging strategies are realized under different hydrostatic pressure regimes. Hypobaric hypoxia that developed in B. nikolskii (a deep-water benthic species) upon delivery to the surface caused distinct destructive changes in cells of the olfactory epithelium. In C. baicalensis and C. inermis, whose foraging behavior involves daily vertical migrations between deep and shallow layers, these cells are characterized by a significantly higher structural and functional stability than in deep-water B. nikolskii. The results of morphological study and quantitative analysis of functionally active mitochondria in cells of the olfactory epithelium of closely related deep-water fish species with different modes of life provide evidence that tolerance of the olfactory apparatus to hypobaric hypoxia is different in pelagic and benthic species. These results help elucidate the mechanisms responsible for the consistent functioning of the olfactory system in animals evolutionarily adapted to extreme environmental factors, and provide theoretical and practical implications in different fields of biology, neurology and extreme medicine.

Rearrangement of Actin Microfilaments in the Development of Olfactory Receptor Cells in Fish

“…The OE has a structure typical of teleosts and consists of receptor, supporting, and basal cells 20 – 22 . Based on transmission microscopy data, the OE has two types of receptor cells – ciliated and microvillar – of which the former prevail in number 23 . Confocal microscopy shows that within 12 h after BrdU injection, proliferatively active cells are detected in the basal area of all the folds of the olfactory rosette (Fig.…”

“…Therefore, these cells acquire contours typical of the dendrites of ciliated and microvillar OSNs, which we observed in the OE of C . inermis by transmission microscopy 23 . The top of a ciliary OSN contains cilia (Fig.…”

“…Cytochemical data on the OSN cytoskeleton that has been detected by confocal microscopy was compared with the morphological features of OSNs, studied earlier with electron microscopy in C . inermis 23 . The olfactory epithelium has ciliated supporting cells (cSC) and secretory supporting cells (sSC).…”