Accessory nerve fibres in simple sensory corpuscles in the hedgehog

Studying the ultrastructure of simple sensory corpuscles in the glabrous skin in the hedgehog snout the authors followed the accessory nerve fibres in the examined corpuscles. The accessory nerve fibres were divided into four groups: a) The accessory nerve fibres containing accumulated mitochondria in the inner core. Here the fibres were situated among the peripheral lamellae of the inner core with which they are occasionally joined though desmosomes. b) The accessory nerve fibre in the inner core containing more light vesicles but lacking completely mitochondria. c) The accessory nerve fibre rich in mitochondria between the inner core and the capsule. d) The bundle of nerve fibres among the capsular lamellae. This bundle included a fibre rich in mitochondria, the other fibres contained mitochondria sporadically. There were nor vesicles at all. The authors are of the view that the fibres of groups a), c), and d) are sensory fibres including the fibres in group d) containing sporadic mitochondria. For the time being it is not quite clear wheather the accessory fibre in the inner core is independent from the very beginning or whether it is a branch of the central axon. The nature of the fibre of group b) rich in vesicles is not quite clear. With respect to the fact that the material was fixed in glutaraldehyde the findings will have to be completed by further material fixed in potassium permanganate or by enzymatic examination. Further examinations will also be inevitable to determine a possible functon of accessory fibres in the sensory terminal.