Anatomy and Ultrastructural Observations of Nasal Neuroepithelium of Pseudapocryptes Lanceolatus (bloch and Schneider)

The olfaction in fish is generally related with water ventilation process. This study emphasized on the surface structures of the olfactory neuroepithelium and cytological details of the ciliated epithelial elements (i.e., ciliated sensory receptor cells and ciliated supporting cells) in relation to olfaction during water ventilation in a mudskipper, Pseudapocryptes lanceolatus; a teleostean: gobiid fish of SouthEast Asia. The olfactory apparatus is well connected with anterior and posterior nostril respectively through the integral nasal cavity of olfactory lamella. The nasal cavity is lined by pseudostratified olfactory neuroepithelium. Under scanning electron microscopical (SEM) study, the surface of the olfactory neuroepithelium of P. lanceolatus shows olfactory knobs with either cilia or microvilli, flat surfaces with numerous cilia, polygonal microridges (average width 0.2 m), mucous secretory pores with different diameter (0.5 m to 1.5 m), mucous secretion, etc. The morphological and subcellular differences of the ciliated sensory receptor cell and ciliated supporting cell have been studied under transmission electron microscope (TEM). The fine structural details indicate that ciliated supporting cell are non sensory in nature and directly involved in water ventilation but the ciliated sensory receptor cell may play crucial role in detection and discrimination of chemical cues from the external aquatic environment.