The Morphology of the Rat Vibrissal Follicle-Sinus Complex Revealed by Three-Dimensional Computer-Aided Reconstruction

The vibrissal follicle-sinus complex (FSC) is a sensory receptor of the mammalian integumentary system that is located around the mouth. The purpose of the present study was to identify the actual 3-dimensional structure of the rat vibrissal FSC. Rat skin tissue was serially sectioned at a thickness of 10 µm and then stained with Masson’s trichrome. The serial sections were reconstructed 3-dimensionally using Reconstruct software. The rat vibrissal follicle is a spindle-shaped structure that is embedded within a blood sinus and enveloped within a thick collagenous capsule. The vibrissal FSC is innervated by the deep vibrissal and superficial vibrissal nerves. The deep vibrissal nerve, travelling in the basal-to-apical direction, penetrates the thick collagenous capsule of the vibrissal FSC. The sinus system can be divided into a superior portion, known as the ring sinus, and an inferior portion, known as the cavernous sinus. The ring sinus contains a C-shaped structure, the ringwulst, which is suspended from the mesenchymal sheath of the follicle. Collagenous trabeculae can be seen in the cavernous sinus but not in the ring sinus. The ring sinus encircles the follicle obliquely and asymmetrically. The ringwulst encircles the follicle incompletely, in a C-shaped fashion. This study has demonstrated the previously underappreciated 3-dimensional structure of the vibrissal FSC, which differs from previously reported descriptions, and provides data that will enhance the understanding of vibrissal function.

[1]  X. Tong,et al.  Vibrissa hair bulge houses two populations of skin epithelial stem cells distinct by their keratin profile , 2008, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[2]  O. Ohtani,et al.  The three-dimensional microvascular and collagen fibrillar arrangements around rat vibrissa hairs as revealed by scanning electron microscopy , 1994, Medical Electron Microscopy.

[3]  D. Kleinfeld,et al.  Frisking the Whiskers Patterned Sensory Input in the Rat Vibrissa System , 2004, Neuron.

[4]  [On the microstructure of receptors on sinus hair]. , 1966, Zeitschrift fur Zellforschung und mikroskopische Anatomie.

[5]  C. Jahoda,et al.  In vivo induction of hair growth by dermal cells isolated from hair follicles after extended organ culture. , 2001, The Journal of investigative dermatology.

[6]  M. Jacquin,et al.  Dual innervation of the rat vibrissa: Responses of trigeminal ganglion cells projecting through deep or superficial nerves , 1992, The Journal of comparative neurology.

[7]  T. Yohro.  Structure of the sinus hair follicle in the big‐clawed shrew, Sorex unguiculatus , 1977, Journal of morphology.

[8]  T. Kealey,et al.  Cyclical changes in rat vibrissa follicles maintained In vitro. , 2000, The Journal of investigative dermatology.

[9]  Karl Hermann Andres,et al.  Über die Feinstruktur der Rezeptoren an Sinushaaren , 2004, Zeitschrift für Zellforschung und Mikroskopische Anatomie.

[10]  P. Waite,et al.  Unmyelinated innervation of sinus hair follicles in rats , 1993, Anatomy and Embryology.

[11]  A. Iggo,et al.  Functional characteristics of mechanoreceptors in sinus hair follicles of the cat , 1973, The Journal of physiology.

[12]  J C Fiala,et al.  Reconstruct: a free editor for serial section microscopy , 2005, Journal of microscopy.

[13]  F. Rice,et al.  Innervation of nonmystacial vibrissae in the adult rat , 1995, The Journal of comparative neurology.

[14]  L. Wineski.  Facial morphology and vibrissal movement in the golden hamster , 1985, Journal of morphology.

[15]  F. Rice,et al.  Adaptations in the structure and innervation of follicle‐sinus complexes to an aquatic environment as seen in the Florida manatee (Trichechus manatus latirostris) , 2007, The Journal of comparative neurology.

[16]  Y. Tamatsu,et al.  Vestiges of vibrissal capsular muscles exist in the human upper lip , 2007, Clinical anatomy.

[17]  D. Simons,et al.  9 – Somatosensory Development , 1981 .

[18]  E Nevo,et al.  Adaptive differentiations of the skin of the head in a subterranean rodent, Spalax ehrenbergi , 1997, Journal of morphology.

[19]  K. Koh,et al.  A new model for the morphology of the arrector pili muscle in the follicular unit based on three‐dimensional reconstruction , 2006, Journal of anatomy.

[20]  K. Koh,et al.  Multiunit arrector pili muscular structure as a variation observed by using computer-based three-dimensional reconstruction , 2005, Cell and Tissue Research.

[21]  E. Ahissar,et al.  Encoding of Vibrissal Active Touch , 2003, Neuron.

[22]  B. Munger,et al.  Successive waves of differentiation of cutaneous afferents in rat mystacial skin , 1986, The Journal of comparative neurology.

[23]  B. Munger,et al.  Degeneration and regeneration of peripheral nerve in the rat trigeminal system. I. Identification and characterization of the multiple afferent innervation of the mystacial vibrissae , 1986, The Journal of comparative neurology.

[24]  H. Takahashi-Iwanaga.  Three‐dimensional microanatomy of longitudinal lanceolate endings in rat vibrissae , 2000, The Journal of comparative neurology.

[25]  G. Dehnhardt,et al.  Structure and innervation of the vibrissal follicle‐sinus complex in the Australian water rat, Hydromys chrysogaster , 1999, The Journal of comparative neurology.

[26]  J. Dörfl.  The musculature of the mystacial vibrissae of the white mouse. , 1982, Journal of anatomy.

[27]  Bernd Fritzsch,et al.  Innervation of the maxillary vibrissae in mice as revealed by anterograde and retrograde tract tracing , 2004, Cell and Tissue Research.

[28]  F. Rice.  Structure, vascularization, and innervation of the mystacial pad of the rat as revealed by the lectin griffonia simplicifolia , 1993, The Journal of comparative neurology.

[29]  K. Kovacs,et al.  Microstructure and innervation of the mystacial vibrissal follicle-sinus complex in bearded seals, Erignathus barbatus (Pinnipedia: Phocidae). , 2006, The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology.

[30]  F. Rice,et al.  Similarities and differences in the innervation of mystacial vibrissal follicle–sinus complexes in the rat and cat: A confocal microscopic study , 2002, The Journal of comparative neurology.

[31]  E. Gibson,et al.  The development of perception , 1983 .

[32]  P. Ernfors,et al.  A rapid and dynamic regulation of GDNF-family ligands and receptors correlate with the developmental dependency of cutaneous sensory innervation. , 1999, Development.

[33]  R. Oliver,et al.  Morphological changes associated with the growth cycle of vibrissal follicles in the rat. , 1976, Journal of embryology and experimental morphology.

[34]  B. Munger,et al.  A comparative light microscopic analysis of the sensory innervation of the mystacial pad. I. Innervation of vibrissal follicle‐sinus complexes , 1986, The Journal of comparative neurology.

[35]  Andres Kh.  On the microstructure of receptors on sinus hair , 1966 .

[36]  K. Koh,et al.  A study of the secretion mechanism of the sebaceous gland using three‐dimensional reconstruction to examine the morphological relationship between the sebaceous gland and the arrector pili muscle in the follicular unit , 2007, The British journal of dermatology.

[37]  F. Rice,et al.  Comprehensive immunofluorescence and lectin binding analysis of vibrissal follicle sinus complex innervation in the mystacial pad of the rat , 1997, The Journal of comparative neurology.

[38]  F. Rice,et al.  Different distributions of the sensory and autonomic innervation among the microvasculature of the rat mystacial pad , 1997, The Journal of comparative neurology.