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Do Developing Merkel Cells in Vibrissal Tactile Receptors Provide a Template for Pattern Formation in the Trigeminal System?

  • Colin Nurse
  • Laura Farraway

Abstract

The trigeminal pathway in rodents has served as an important model for studying pattern formation in the central nervous system. In this pathway there is a topographic point-to-point relation between the array of mystacial vibrissae on the whisker pad and their central projections in the barrel-field of the somatosensory cortex (Woolsey and Van der Loos, 1970; Welker, 1976; Belford and Killackey, 1980). Among the peripheral receptor sites the aggregates of Merkel cells, which are involved in tactile sensation in the vibrissal follicles, have been proposed as candidates for the master pattern or template for the central maps (Killackey, 1980). Support for this idea would be strengthened if the development of Merkel cells in the vibrissae should occur independently of retrograde influences within the whisker-to-barrel pathway. To test this we have investigated in the rat the effects of neonatal deafferentation of the whisker pad on Merkel cell development in the vibrissae using the quinacrine fluorescence technique (Nurse et al., 1983). Merkel cells are also present in the overlying whisker pad epidermis and these provided an additional population for comparing the effects of denervation. Since the method permits rigorous quantification of Merkel cell populations, this study was expected to address further the controversial issue of the role of sensory nerves on the development and maintenance of Merkel cells in different epithelial locations (Nurse et al., 1984).

Keywords

Somatosensory Cortex Outer Root Sheath Infraorbital Nerve Trigeminal System Master Pattern 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Beiford, G.R., and Killackey, H.P., 1980, The sensitive period in the development of the trigeminal system of the neonatal rat. J. Comp. Neurol., 193: 335–350.CrossRefGoogle Scholar
  2. Benkenstein, M., 1979, Veränderungen der Ultrastruktur der Merkeischen Nervenendigungen an Sinushaaren von Ratten nach Denervation. Acta Anat. 105: 409–422.PubMedCrossRefGoogle Scholar
  3. Diamond, J., 1982, Modelling and competition in the nervous system: clues from the sensory innervation of skin. Curr. Top. Develop. Biol., 17: 147–205.CrossRefGoogle Scholar
  4. English, K.B., 1977, The ultrastructure of cutaneous type 1 mechanorecep tors (Haarscheiben) in cats following denervation. J. Comp. Neurol., 172: 137–164.PubMedCrossRefGoogle Scholar
  5. Hartschuh, W., and Weihe, E., 1977, The effect of denervation on Merkel cells in cats. Neurosci. Letts. 5: 327–332.CrossRefGoogle Scholar
  6. Killackey, H.P., 1980, Pattern formation in the trigeminal system of the rat. Trends Neurosci. 3: 303–306.Google Scholar
  7. Mills, L., Nurse, C.A., and Diamond, J., 1984, Regional differences in the sensory nerve dependence of Merkel cell development in rat skin. Soc. Neurosci. Abstr. 10: 1058.Google Scholar
  8. Nurse, C.A., Mearow, K.M., Holmes, M., Visheau, B., and Diamond, J., 1983, Merkel cell distribution in the epidermis as determined by quinacrine fluorescence. Cell Tiss. Res. 228: 511–524.Google Scholar
  9. Nurse, C.A., MacIntyre, L., and Diamond, J., 1984, A quantitative study of the time course of the reduction in Merkel cell number within denervated rat touch domes. Neurosci., 11: 521–533.CrossRefGoogle Scholar
  10. Palmer, P. 1965. Ultrastructural alterations of Merkel cells following denervation. Anat. Rec. 151: 396–397.Google Scholar
  11. Renehan, W.E., and Munger, B.L., 1986, Degeneration and regeneration of peripheral nerve in the rat trigeminal system. II. Response to nerve lesions. J. Comp. Neurol., 249: 429–459.PubMedCrossRefGoogle Scholar
  12. VanExan, R.J., and Hardy, M.H., 1980, A spatial relationship between innervation and the early differentiation of vibrissa follicles in the embryonic mouse. J. Anat., 131: 643–656.PubMedGoogle Scholar
  13. Welker, C., 1976, Receptive fields of barrels in the somatosensory neo cortex of the rat. J. Comp. Neurol. 166: 173–190.PubMedCrossRefGoogle Scholar
  14. Woolsey, T.A., and Van der Loos, H., 1970, The structural organization of layer IV in the somatosensory region (SI) of mouse cerebral cortex. Brain Res. 17: 205–242.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • Colin Nurse
    • 1
  • Laura Farraway
    • 1
  1. 1.Department of BiologyMcMaster UniversityHamiltonCanada

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