Unique nasal septal island in dromedary camels may play a role in pain perception: microscopic studies

Ultrastructure and histochemistry of the subepithelial glands of the nasal septal island in dromedaries with special reference to the possible functions

“…The anatomical peculiarities of the glandular cells were suggestive for APUD system. These glands are supposed to be specialized for assisting the NSI neuroepithelium in functions related to pain perception ( Abo-Ahmed et al, 2021 ). This possible function depends on the type of proteins, amines and chemical mediators, which the glandular APUD cells are able to produce.…”

“…The nasal septal island (NSI) in dromedaries is a unique anatomical structure, formed of a patch of sensory epithelium, located in the rostro-dorsal part of the nasal septum and innervated by the ethmoidal branch of the trigeminal nerve ( Abo-Ahmed et al, 2021 ). Interestingly, this sensory island was associated with three sets of glands, including submucosal, subepithelial, and intraepithelial glands as described by the previous authors.…”

“…All the above-mentioned information, raises the question, why such type of cells would be important in the nasal mucosa, namely in the NSI subepithelial glands? This could be addressed by the topographical context, as they are located within the chemosensory field of the ethmoidal nerve, suggestive for pain perception ( Abo-Ahmed et al, 2021 ). Similar to other parts of mucosa, the nasal mucosa requires coordinating immune response with detection of noxious stimuli.…”

Merkel-like basal cells in the nasal septal island of dromedaries: Ultrastructure and possible functions

“…The septal organs are patches of chemosensory cells situated in the ventral parts of the nasal septum of many mammals and innervated by the olfactory nerve ( Ma et al, 2003 ). However, a recent study revealed a unique nasal septal island of sensory epithelium situated in the dorso-medial part of the nasal vestibule of dromedaries ( Camelus dromedarius ) innervated by the ethmoidal branch of trigeminal nerve, and is believed to be involved in pain perception or nociception ( Abo-Ahmed et al, 2021 ). Resembling other areas of somatosensory innervation, the trigeminal innervation contains Merkel cells, which are most frequently linked to sensory nerve ends.…”

“…Resembling other areas of somatosensory innervation, the trigeminal innervation contains Merkel cells, which are most frequently linked to sensory nerve ends. The trigeminal nerve endings in the NSI are surrounded by clusters of Merkel-like cells ( Abo-Ahmed et al, 2021 ). However, during electron microscopic examination of the NSI tissues, the authors observed that some basal cells closely resembled Merkel cells.…”