Open AccessElectrical Stimulation of Dorsal Root Entry Zone Attenuates Wide‐Dynamic‐Range Neuronal Activity in Rats
Author(s) -
Yang Fei,
Zhang Chen,
Xu Qian,
Tiwari Vinod,
He ShaoQiu,
Wang Yun,
Dong Xinzhong,
VeraPortocarrero Louis P.,
Wacnik Paul W.,
Raja Srinivasa N.,
Guan Yun
Publication year - 2015
Publication title -
neuromodulation: technology at the neural interface
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 60
eISSN - 1525-1403
pISSN - 1094-7159
DOI - 10.1111/ner.12249
Subject(s) - stimulation , chemistry , neuropathic pain , premovement neuronal activity , in vivo , medicine , antidromic , anesthesia , neuroscience , endocrinology , biology , microbiology and biotechnology
Objectives Recent clinical studies suggest that neurostimulation at the dorsal root entry zone ( DREZ ) may alleviate neuropathic pain. However, the mechanisms of action for this therapeutic effect are unclear. Here, we examined whether DREZ stimulation inhibits spinal wide‐dynamic‐range ( WDR ) neuronal activity in nerve‐injured rats. Materials and Methods We conducted in vivo extracellular single‐unit recordings of WDR neurons in rats after an L5 spinal nerve ligation ( SNL ) or sham surgery. We set bipolar electrical stimulation (50 Hz, 0.2 msec, 5 min) of the DREZ at the intensity that activated only Aα /β‐fibers by measuring the lowest current at which DREZ stimulation evoked a peak antidromic sciatic Aα /β‐compound action potential without inducing an Aδ / C ‐compound action potential (i.e., Ab1 ). Results The elevated spontaneous activity rate of WDR neurons in SNL rats ( n = 25; data combined from post‐ SNL groups at days 14–16 [ n = 15] and days 45–75 [ n = 10]) was significantly decreased from the prestimulation level ( p < 0.01) at 0–15 min and 30–45 min post‐stimulation. In both sham‐operated ( n = 8) and nerve‐injured rats, DREZ stimulation attenuated the C ‐component, but not the A ‐component, of the WDR neuronal response to graded intracutaneous electrical stimuli (0.1–10 mA, 2 msec) applied to the skin receptive field. Further, DREZ stimulation blocked windup (a form of brief neuronal sensitization) to repetitive noxious stimuli (0.5 Hz) at 0–15 min in all groups ( p < 0.05). Conclusions Attenuation of WDR neuronal activity may contribute to DREZ stimulation‐induced analgesia. This finding supports the notion that DREZ may be a useful target for neuromodulatory control of pain.