Perineural dexmedetomidine added to ropivacaine causes a dose-dependent increase in the duration of thermal antinociception in sciatic nerve block in rat

Chad M. Brummett, Amrita K. Padda, Francesco S. Amodeo, Kathleen B. Welch, Ralph Lydic

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

BACKGROUND:: The current study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would increase the duration of antinociception to a thermal stimulus in a dose-dependent fashion in a rat model of sciatic nerve blockade. METHODS:: Fifty adult Sprague-Dawley rats (10 rats/group) received unilateral sciatic nerve blocks with 0.2 ml ropivacaine (0.5%) or 0.2 ml ropivacaine (0.5%) plus dexmedetomidine (2.7 μm [0.5 μg/kg], 11.7 μm [2 μg/kg], 34.1 μm [6 μg/kg], or 120.6 μm [20 μg/kg]) in a randomized, blinded fashion. Time to paw withdrawal latency to a thermal stimulus for both paws and an assessment of motor function were measured every 30 min after the nerve block until a return to baseline. RESULTS:: Dexmedetomidine added to ropivacaine increased the duration of dense sensory blockade and time for return to normal sensory function in a dose-dependent fashion (P < 0.005). There was a significant time (P < 0.005), dose (P < 0.005), and time-by-dose effect (P < 0.005) on paw withdrawal latencies of the operative paws. There were no significant differences in paw withdrawal latencies of the control paws, indicating little systemic effect of the dexmedetomidine. The duration of motor blockade was also increased with dexmedetomidine. High-dose dexmedetomidine (120.6 μm) was not neurotoxic. CONCLUSION:: This is the first study showing that dexmedetomidine added to ropivacaine increases the duration of sensory blockade in a dose-dependent fashion in rats. The findings are an essential first step encouraging future efficacy studies in humans.

Original languageEnglish (US)
Pages (from-to)1111-1119
Number of pages9
JournalAnesthesiology
Volume111
Issue number5
DOIs
StatePublished - Jan 1 2009

Fingerprint

Dexmedetomidine
Nerve Block
Sciatic Nerve
Hot Temperature
ropivacaine
Sprague Dawley Rats

All Science Journal Classification (ASJC) codes

  • Anesthesiology and Pain Medicine

Cite this

Perineural dexmedetomidine added to ropivacaine causes a dose-dependent increase in the duration of thermal antinociception in sciatic nerve block in rat. / Brummett, Chad M.; Padda, Amrita K.; Amodeo, Francesco S.; Welch, Kathleen B.; Lydic, Ralph.

In: Anesthesiology, Vol. 111, No. 5, 01.01.2009, p. 1111-1119.

Research output: Contribution to journalArticle

Brummett, Chad M. ; Padda, Amrita K. ; Amodeo, Francesco S. ; Welch, Kathleen B. ; Lydic, Ralph. / Perineural dexmedetomidine added to ropivacaine causes a dose-dependent increase in the duration of thermal antinociception in sciatic nerve block in rat. In: Anesthesiology. 2009 ; Vol. 111, No. 5. pp. 1111-1119.
@article{02b30716f1a84b65a5ec0f56ddc11637,
title = "Perineural dexmedetomidine added to ropivacaine causes a dose-dependent increase in the duration of thermal antinociception in sciatic nerve block in rat",
abstract = "BACKGROUND:: The current study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would increase the duration of antinociception to a thermal stimulus in a dose-dependent fashion in a rat model of sciatic nerve blockade. METHODS:: Fifty adult Sprague-Dawley rats (10 rats/group) received unilateral sciatic nerve blocks with 0.2 ml ropivacaine (0.5{\%}) or 0.2 ml ropivacaine (0.5{\%}) plus dexmedetomidine (2.7 μm [0.5 μg/kg], 11.7 μm [2 μg/kg], 34.1 μm [6 μg/kg], or 120.6 μm [20 μg/kg]) in a randomized, blinded fashion. Time to paw withdrawal latency to a thermal stimulus for both paws and an assessment of motor function were measured every 30 min after the nerve block until a return to baseline. RESULTS:: Dexmedetomidine added to ropivacaine increased the duration of dense sensory blockade and time for return to normal sensory function in a dose-dependent fashion (P < 0.005). There was a significant time (P < 0.005), dose (P < 0.005), and time-by-dose effect (P < 0.005) on paw withdrawal latencies of the operative paws. There were no significant differences in paw withdrawal latencies of the control paws, indicating little systemic effect of the dexmedetomidine. The duration of motor blockade was also increased with dexmedetomidine. High-dose dexmedetomidine (120.6 μm) was not neurotoxic. CONCLUSION:: This is the first study showing that dexmedetomidine added to ropivacaine increases the duration of sensory blockade in a dose-dependent fashion in rats. The findings are an essential first step encouraging future efficacy studies in humans.",
author = "Brummett, {Chad M.} and Padda, {Amrita K.} and Amodeo, {Francesco S.} and Welch, {Kathleen B.} and Ralph Lydic",
year = "2009",
month = "1",
day = "1",
doi = "10.1097/ALN.0b013e3181bbcc26",
language = "English (US)",
volume = "111",
pages = "1111--1119",
journal = "Anesthesiology",
issn = "0003-3022",
publisher = "Lippincott Williams and Wilkins",
number = "5",

}

TY - JOUR

T1 - Perineural dexmedetomidine added to ropivacaine causes a dose-dependent increase in the duration of thermal antinociception in sciatic nerve block in rat

AU - Brummett, Chad M.

AU - Padda, Amrita K.

AU - Amodeo, Francesco S.

AU - Welch, Kathleen B.

AU - Lydic, Ralph

PY - 2009/1/1

Y1 - 2009/1/1

N2 - BACKGROUND:: The current study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would increase the duration of antinociception to a thermal stimulus in a dose-dependent fashion in a rat model of sciatic nerve blockade. METHODS:: Fifty adult Sprague-Dawley rats (10 rats/group) received unilateral sciatic nerve blocks with 0.2 ml ropivacaine (0.5%) or 0.2 ml ropivacaine (0.5%) plus dexmedetomidine (2.7 μm [0.5 μg/kg], 11.7 μm [2 μg/kg], 34.1 μm [6 μg/kg], or 120.6 μm [20 μg/kg]) in a randomized, blinded fashion. Time to paw withdrawal latency to a thermal stimulus for both paws and an assessment of motor function were measured every 30 min after the nerve block until a return to baseline. RESULTS:: Dexmedetomidine added to ropivacaine increased the duration of dense sensory blockade and time for return to normal sensory function in a dose-dependent fashion (P < 0.005). There was a significant time (P < 0.005), dose (P < 0.005), and time-by-dose effect (P < 0.005) on paw withdrawal latencies of the operative paws. There were no significant differences in paw withdrawal latencies of the control paws, indicating little systemic effect of the dexmedetomidine. The duration of motor blockade was also increased with dexmedetomidine. High-dose dexmedetomidine (120.6 μm) was not neurotoxic. CONCLUSION:: This is the first study showing that dexmedetomidine added to ropivacaine increases the duration of sensory blockade in a dose-dependent fashion in rats. The findings are an essential first step encouraging future efficacy studies in humans.

AB - BACKGROUND:: The current study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would increase the duration of antinociception to a thermal stimulus in a dose-dependent fashion in a rat model of sciatic nerve blockade. METHODS:: Fifty adult Sprague-Dawley rats (10 rats/group) received unilateral sciatic nerve blocks with 0.2 ml ropivacaine (0.5%) or 0.2 ml ropivacaine (0.5%) plus dexmedetomidine (2.7 μm [0.5 μg/kg], 11.7 μm [2 μg/kg], 34.1 μm [6 μg/kg], or 120.6 μm [20 μg/kg]) in a randomized, blinded fashion. Time to paw withdrawal latency to a thermal stimulus for both paws and an assessment of motor function were measured every 30 min after the nerve block until a return to baseline. RESULTS:: Dexmedetomidine added to ropivacaine increased the duration of dense sensory blockade and time for return to normal sensory function in a dose-dependent fashion (P < 0.005). There was a significant time (P < 0.005), dose (P < 0.005), and time-by-dose effect (P < 0.005) on paw withdrawal latencies of the operative paws. There were no significant differences in paw withdrawal latencies of the control paws, indicating little systemic effect of the dexmedetomidine. The duration of motor blockade was also increased with dexmedetomidine. High-dose dexmedetomidine (120.6 μm) was not neurotoxic. CONCLUSION:: This is the first study showing that dexmedetomidine added to ropivacaine increases the duration of sensory blockade in a dose-dependent fashion in rats. The findings are an essential first step encouraging future efficacy studies in humans.

UR - http://www.scopus.com/inward/record.url?scp=70350461546&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70350461546&partnerID=8YFLogxK

U2 - 10.1097/ALN.0b013e3181bbcc26

DO - 10.1097/ALN.0b013e3181bbcc26

M3 - Article

C2 - 19858875

AN - SCOPUS:70350461546

VL - 111

SP - 1111

EP - 1119

JO - Anesthesiology

JF - Anesthesiology

SN - 0003-3022

IS - 5

ER -