Embryonic development of the specific vestibular hair cell pathology in a strain of the waltzing guinea pig.
The cytodifferentiation and maturation of vestibular hair cells, and the pathological development of vestibular type I hair cells, were followed in a strain of the waltzing guinea pig. The hair cells are first identified on the 30th gestational day. During the next 7-10 days the number of hair cells increases considerably in parallel with cytodifferentiation: the development of stereocilia, the cuticular plate, the afferent nerve terminals and the formation of synaptic contacts. On the 48th gestational day efferent nerve terminals are identified as are also a large number of fully developed nerve calyces. Differentiation into hair cells type I and type II was clearly evident at this stage. The first pathological finding appeared on the 38th gestational day as fusion of stereocilia. Actin filament rods in type I hair cells are identified with certainty on the 60th gestational day. In parallel with the in vivo development, inner ear explants (30-50th gestational days) were cultured in vitro. In this material actin filament rods were found already in 30th gestational day explants cultured 8 days in vitro. At this stage also hair cell protrusion and sensory hair fusion occurred.
D000818:Animals; D002454:Cell Differentiation; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000648:ultrastructure; D009924:Organ Culture Techniques; D011247:Pregnancy; D013569:Synapses / Q000648:ultrastructure; D014722:Vestibule, Labyrinth / Q000166:cytology / Q000196:embryology* / Q000294:innervation