Zolmitriptan Reduces the Size of the Neurogenic Flare Reaction and the Primary Hyperalgesia after Electrical Stimulation

The contribution for the development of secondary mechanical hyperalgesia by peripheral mechanisms has not been fully elucidated. We have reevaluated the effects of local anesthetics on electrically evoked flare reaction and mechanical hyperalgesia in human skin. We applied 2% lidocaine via intradermal microdialysis fibers at a length of 10 cm for 110 min to the volar forearm to establish a narrow and stable “anesthetic strip.” After 60 min of lidocaine perfusion, transdermal electrical stimulation (1 Hz, 50 mA) was applied at a distance of 1 cm from the microdialysis fibers for 30 min. The areas of allodynia and punctate hyperalgesia were marked at the end of the stimulation period. The flare reaction was assessed by laser Doppler scanner and infrared thermography. Total protein content of the dialysate collected at the stimulating electrode was measured photometrically. We found no increase in protein content during electrical stimulation. Flare area (12.4 ± 2.3 vs. 3.5 ± 1.2 cm2) and intensity (426 ± 24 vs. 257 ± 21 PU) were significantly reduced beyond the lidocaine strip. The mean temperature increase in the area beyond the lidocaine strip was significantly reduced (1.1 ± 0.1 vs. 0.2 ± 0.1°C) and did not differ from control areas. In contrast, allodynia (7.4 ± 0.7 and 8.6 ± 0.9 cm) and punctate hyperalgesia (7.6 ± 0.7 and 8.6 ± 0.9 cm) developed symmetrically on both sides of the anesthetic strip. Allodynia subsided 4 min after the end of the electrical stimulation. We conclude that the development of allodynia and punctate hyperalgesia in human skin is centrally mediated, whereas the axon reflex vasodilation is of peripheral origin.

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Decreased Axon Flare Reaction to Electrical Stimulation in Patients With Chronic Demyelinating Inflammatory Polyneuropathy

Journal of Clinical Neurophysiology ◽

10.1097/wnp.0000000000000294 ◽

2017 ◽

Vol 34 (2) ◽

pp. 101-106 ◽

Cited By ~ 1

Author(s):

Panagiotis Kokotis ◽

Martin Schmelz ◽

Aikaterini E. Papagianni ◽

Thomas Zambelis ◽

Nikos Karandreas

Keyword(s):

Electrical Stimulation ◽

Flare Reaction ◽

Inflammatory Polyneuropathy

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Two Types of C Nociceptors in Human Skin and Their Behavior in Areas of Capsaicin-Induced Secondary Hyperalgesia

Journal of Neurophysiology ◽

10.1152/jn.00565.2003 ◽

2004 ◽

Vol 91 (6) ◽

pp. 2770-2781 ◽

Cited By ~ 88

Author(s):

Jordi Serra ◽

Mario Campero ◽

Hugh Bostock ◽

José Ochoa

Keyword(s):

Electrical Stimulation ◽

Discrete Series ◽

Intradermal Injection ◽

Repetitive Stimulation ◽

Mechanical Stimuli ◽

Secondary Hyperalgesia ◽

Stimulation Protocol ◽

C Fiber ◽

Primary Hyperalgesia ◽

Stimulation Of

Peripheral nociceptor sensitization is accepted as an important mechanism of cutaneous primary hyperalgesia, but secondary hyperalgesia has been attributed to central mechanisms since evidence for sensitization of primary afferents has been lacking. In this study, microneurography was used to test for changes in sensitivity of C nociceptors in the area of secondary hyperalgesia caused by intradermal injection of capsaicin in humans. Multiple C units were recruited by electrical stimulation of the skin at 0.25 Hz and were identified as discrete series of dots in raster plots of spike latencies. Nociceptors slowed progressively during repetitive stimulation at 2 Hz for 3 min. According to their response to mechanical stimulation, nociceptors could be classified as either mechano-sensitive (CM) or mechano-insensitive (CMi). These two nociceptor subtypes had different axonal properties: CMi units slowed by 2% or more when stimulated at 0.25 Hz after a 3-min pause, whereas CM units slowed by <1%. This stimulation protocol was used before capsaicin injection to identify nociceptor subtype without repeated probing, thus avoiding possible mechanical sensitization. Capsaicin, injected 10–50 mm away from the site of electrical stimulation, had no effect on any of 29 CM units, but induced bursts of activity in 11 of 15 CMi units, after delays ranging from 0.5 to 18 min. The capsaicin injections also sensitized a majority of the CMi units, so that 11 of 17 developed immediate or delayed responsiveness to mechanical stimuli. This sensitization may contribute a peripheral C fiber component to secondary hyperalgesia.

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The “KIMWIPE” Effect in Ultra-Thin Cryosections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119119 ◽

1985 ◽

Vol 43 ◽

pp. 458-459

Author(s):

I. Taylor ◽

P. Ingram ◽

J.R. Sommer

Keyword(s):

Skeletal Muscle ◽

Electrical Stimulation ◽

Muscle Fibers ◽

Ice Crystals ◽

Crystal Formation ◽

Ice Crystal ◽

Thin Sections ◽

Skeletal Muscle Fibers ◽

Freeze Dried ◽

Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

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