| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
The Journal of Neurophysiology Vol. 88 No. 4 October 2002, pp. 1859-1866
Copyright ©2002 by the American Physiological Society
1Department of Clinical Neurophysiology, University of Uppsala, 751 85 Uppsala, Sweden; and 2Department of Physiology and Experimental Pathophysiology, Universitätsstr 17, University of Erlangen/Nürnberg, Germany
Schmidt, R.,
M. Schmelz,
C. Weidner,
H. O. Handwerker, and
H. E. Torebjörk.
Innervation Territories of Mechano-Insensitive C Nociceptors
in Human Skin. J. Neurophysiol. 88: 1859-1866, 2002. Microneurographic recordings were obtained in the
peroneal nerve from 20 mechano-insensitive units (CMi) and six
mechano-heat responsive C units (CMH) in healthy human subjects. Their
innervation territories in the skin of the leg or foot were assessed by
transcutaneous electrical stimulation with a pointed probe at
intensities of 10 to 100 mA (0.2 ms) and, when applicable, by
mechanical von Frey hair stimulation. Electro-receptive fields (eRFs)
of CMH units had a median area of 1.95 cm2 when
mapped with 10 mA that coincided approximately with mechano-receptive fields (mRFs) as mapped with a 750-mN von Frey hair. Fifty-milliampere stimuli increased the eRFs to 3.08 cm2 in a
concentric manner. This was probably due to current spread since these
units are known to have low electrical thresholds. Further increase of
the stimulus strength to 70 or 100 mA increased the eRFs only
marginally. Mechano-insensitive units had much smaller eRFs (median:
0.35 cm2) than CMH units when mapped with the
same pointed probe at 10 mA (n = 13). The receptive
territories consisted of one distinct spot or of several spots
separated by distances of more than 1 cm. However, when mapping stimuli
of 50 mA were applied, eRFs became continuous and grew to a median area
of 5.34 cm2, i.e., larger than those of CMHs. The
borders of eRFs of CMi units were significantly more irregular compared
with CMH units. A further increase of the stimulus intensity to a
maximum of 100 mA only marginally enlarged the eRFs. The CMi units
could be activated by heat or chemical substances applied inside the
50-mA eRF, indicating that receptive nerve endings were mapped.
Responsiveness to these stimuli was inhomogeneous within the eRFs. It
was concluded that innervation territories of CMi units in human skin
exceed those of CMH units in size by a factor of approximately 3. The
widely branched terminals underlying the large fields are consistent with a role of this nociceptor class in axon reflex flare and preclude
a role in exact spatial discrimination of noxious stimuli.
This article has been cited by other articles:
|
|
 |
|
  R. W. Carr, S. Pianova, D. D. McKemy, and J. A. Brock Action potential initiation in the peripheral terminals of cold-sensitive neurones innervating the guinea-pig cornea J. Physiol., March 15, 2009; 587(6): 1249 - 1264. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Namer, B. Barta, K. Orstavik, R. Schmidt, R. Carr, M. Schmelz, and H. O. Handwerker Microneurographic assessment of C-fibre function in aged healthy subjects J. Physiol., January 15, 2009; 587(2): 419 - 428. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. Johanek, R. A. Meyer, T. Hartke, J. G. Hobelmann, D. N. Maine, R. H. LaMotte, and M. Ringkamp Psychophysical and Physiological Evidence for Parallel Afferent Pathways Mediating the Sensation of Itch J. Neurosci., July 11, 2007; 27(28): 7490 - 7497. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. S. Ruehle, H. O. Handwerker, J. K. M. Lennerz, R. Ringler, and C. Forster Brain activation during input from mechanoinsensitive versus polymodal C-nociceptors. J. Neurosci., May 17, 2006; 26(20): 5492 - 5499. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Bostock, M. Campero, J. Serra, and J. L. Ochoa Temperature-dependent double spikes in C-nociceptors of neuropathic pain patients Brain, September 1, 2005; 128(9): 2154 - 2163. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. R. Light "Nocifensor" System Re-Revisited. Focus on "Two Types of C Nociceptor in Human Skin and Their Behavior in Areas of Capaicin-Induced Secondary Hyperalgesia" J Neurophysiol, June 1, 2004; 91(6): 2401 - 2403. [Full Text] [PDF]
|
|
|
|
 |
|
 H. H. Kramer, M. Schmelz, F. Birklein, and A. Bickel Electrically Stimulated Axon Reflexes Are Diminished in Diabetic Small Fiber Neuropathies Diabetes, March 1, 2004; 53(3): 769 - 774. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Klede, H. O. Handwerker, and M. Schmelz Central Origin of Secondary Mechanical Hyperalgesia J Neurophysiol, July 1, 2003; 90(1): 353 - 359. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Schmelz, R. Schmidt, C. Weidner, M. Hilliges, H. E. Torebjork, and H. O. Handwerker Chemical Response Pattern of Different Classes of C-Nociceptors to Pruritogens and Algogens J Neurophysiol, May 1, 2003; 89(5): 2441 - 2448. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
