UCLA

The features of many peripheral sensory epithelia have been demonstrated to be labile to altered sensory inputs, however, the extent to which this is a global feature of the peripheral nervous system (PNS) has remained elusive. One way in which this can be studied is through investigations involving genetic mouse models for sensory hypofunction in the vestibular epithelia, since these peripheral structures are normally under constant sensory load throughout life. Here, it was investigated how altering vestibular sensory information to the inner ear epithelia (utricle, horizontal and superior cristae), using the otoferlin-null (Otof-/-) mouse may lead to presynaptic and/or postsynaptic changes in the expression of commonly expressed Ca2+ binding proteins oncomodulin (OCM, �- parvalbumin) or calretinin (CALB2). No alterations were observed in the presynaptic expression of OCM or CALB2, however, there was a marked heterogeneous decrease in postsynaptic CALB2 expression in the Otof-/- epithelia. These results suggest that some epithelial features (postsynaptic CALB2 expression) of the vestibular system are sensitive to the loss of OTOF and dynamic vestibular sensory inputs, while others (presynaptic OCM or CALB2 expression) are not. This may provide insight into how widespread the abilities of PNS sensory structures to adapt to changes in sensory information are, as well as how certain peripheral cellular features within the vestibular system are developed and maintained.