PMID- 14580951
OWN - NLM
STAT- MEDLINE
DCOM- 20040301
LR  - 20190712
IS  - 0306-4522 (Print)
IS  - 0306-4522 (Linking)
VI  - 121
IP  - 4
DP  - 2003
TI  - Altered temporal pattern of mechanically evoked C-fiber activity in a model of 
      diabetic neuropathy in the rat.
PG  - 1007-15
AB  - While enhanced nociceptor activity has been demonstrated in models of painful 
      peripheral neuropathy, analyses of activity pattern, which could play a role in 
      the symptoms experienced as well as help elucidate underlying mechanism, are 
      still limited. We evaluated the pattern of C-fiber activity, in response to 
      mechanical and chemical stimuli, in a rat model of diabetes induced by a 
      pancreatic beta-cell toxin, streptozotocin (STZ). In diabetic rats the number of 
      action potentials produced by threshold and suprathreshold (10 g) sustained (60 
      s) mechanical stimuli was elevated in approximately half of C-fibers. These 
      high-firing C-fibers demonstrated a disproportionate increase in interspike 
      intervals (ISIs) between 100 and 199 ms, compared with low-firing diabetic and 
      control C-fibers. The co-efficient of variability (CV2), a frequency independent 
      measure of ISI variability, was also greater in high-firing fibers, compared with 
      control fibers. Unexpectedly, instantaneous frequency of the initial burst of 
      activity during the first second was lower in high-firing fibers, even though the 
      average frequency over the last 59 s was significantly higher. The number of 
      action potentials evoked by a noxious chemical stimulus, 300 and 600 mM KCl, 
      injected adjacent to the mechanical receptive field was also significantly 
      increased in C-fibers from diabetic rats and mechanically high-firing fibers had 
      more action potentials in response to KCl than control fibers and a 
      disproportionate increase in ISIs between 100 and 199 ms for responses to 
      chemical stimuli appeared only in mechanically high-firing C-fibers, compared 
      with the mechanically low-firing diabetic or control C-fibers. There was, 
      however, no corresponding change in CV2 or instantaneous frequency plots for the 
      response to chemical stimulation in mechanically high-firing fibers, as there was 
      in the response to mechanical stimulation. Our data demonstrate specific changes 
      in firing pattern of high-firing C-fibers in the rat model of painful neuropathy 
      produced by STZ-diabetes that might contribute to the symptoms experienced by 
      patients.
FAU - Chen, X
AU  - Chen X
AD  - Departments of Anatomy, Medicine and Oral and Maxillofacial Surgery, Division of 
      Neuroscience, NIH Pain Center (University of California, San Francisco), C-522 
      Box 0440, University of California, San Francisco, CA 94143-0440, USA.
FAU - Levine, J D
AU  - Levine JD
LA  - eng
GR  - NS21647/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Neuroscience
JT  - Neuroscience
JID - 7605074
RN  - 660YQ98I10 (Potassium Chloride)
SB  - IM
MH  - Action Potentials/drug effects/*physiology
MH  - Animals
MH  - Diabetes Mellitus, Experimental/physiopathology
MH  - Diabetic Neuropathies/*physiopathology
MH  - Disease Models, Animal
MH  - Mechanoreceptors/drug effects/*physiopathology
MH  - Nerve Fibers, Unmyelinated/drug effects/*physiology
MH  - Nociceptors/drug effects/*physiopathology
MH  - Physical Stimulation
MH  - Potassium Chloride/pharmacology
MH  - Rats
MH  - Rats, Sprague-Dawley
EDAT- 2003/10/29 05:00
MHDA- 2004/03/03 05:00
CRDT- 2003/10/29 05:00
PHST- 2003/10/29 05:00 [pubmed]
PHST- 2004/03/03 05:00 [medline]
PHST- 2003/10/29 05:00 [entrez]
AID - S030645220300486X [pii]
AID - 10.1016/s0306-4522(03)00486-x [doi]
PST - ppublish
SO  - Neuroscience. 2003;121(4):1007-15. doi: 10.1016/s0306-4522(03)00486-x.