AYAR A. , KURT A. , Canpolat S.
FEPS 2014, Budapeşte, Hungary, 27 - 30 August 2014, vol.211, no.697, pp.12
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Publication Type:
Conference Paper / Summary Text
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Volume:
211
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City:
Budapeşte
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Country:
Hungary
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Page Numbers:
pp.12
Abstract
Investigation of possible interactions of pain
modification actions of endogenous
enkephalinergic and noradrenergic systems in
Zymosan-induced chronic inflammatory pain
model
A. Ayar, A. Kurt, S. Canpolat
Department of Physiology, Karadeniz Technical University, Faculty of
Medicine, Trabzon-Turkey
Chronic inflammatory pain, a nociceptive process associated with
tissue damage due to inflammation mediated by increased sensitivity
of nociceptive-specific neurons, is a feature of a large number of
painful conditions for which no satisfactory treatment has been
available yet. The aim of this study was to assess the possible
analgesic affects of opiorphin, an endogenous enkephalinase
inhibitior, and noradrenalin, known to be involved in the intrinsic
modulation of nociceptive transmission, on inflammatory pain in rats.
Timing the delay for the first hind paw lift to a focused thermal
radiant heat, in vivo nociceptive behavioral "plantar test" was used for
assessing pain sensitivity of adult male Spraque Dawley rats. After
obtaining control nociceptive latency values, chronic inflammatory
pain was induced by intraplantar injection of zymosan (6 mg in 200
uL) and heat stimulated nociceptive tests were repeated. Pain
threshold values were determined and analyzed by a pairwise
comparison between vehicle and each opiorphin treated group using a
Dunnett's t-test on the ranked data. Zymosan caused a persistent
significant increase in pain sensitivity as measured 15-180 minutes
after its intraplantar injection (P <0.05). Systemic administration of
opiorphin (0.1-0.3 mg/kg) provided a dose dependent (P >0.05 for 0.1
mg/kg opiorphin while P <0.05 for 0.3 mg/kg i.p opiorfin at 30 and
40th min) inhibition of inflammatory pain. Combination of opiorphin
with noradrenalin (1 mg/kg) provided a limited synergic action, and
this effect was reversible by alpha-1 adrenergic blockage (prazosin 1
mg/kg). Results from this study provides some degree of overlap
between endogenous enkephalinergic and noradrenergic analgesic
modification which implicates potential for development of
therapeutical strategies involving combined use of enkephalinase
inhibitors and noradrenergic agonists for the management of persistent
pain associated with inflammatory painful conditions. " tabindex=""
maxlength="2200" onkeyup="charcheck()" style="height:
326px;width: 820px;" >0.05 for 0.1 mg/kg opiorphin while P <0.05
for 0.3 mg/kg i.p opiorfin at 30 and 40th min) inhibition of
inflammatory pain. Combination of opiorphin with noradrenalin (1
mg/kg) provided a limited synergic action, and this effect was
reversible by alpha-1 adrenergic blockage (prazosin 1 mg/kg). Results
from this study provides some degree of overlap between endogenous
enkephalinergic and noradrenergic analgesic modification which
implicates potential for development of therapeutical strategies
involving combined use of enkephalinase inhibitors and noradrenergic
agonists for the management of persistent pain associated with
inflammatory painful conditions. " tabindex="" maxlength="2200"
onkeyup="charcheck()" style="height: 326px;width: 820px;"
>Chronic inflammatory pain, a nociceptive process associated with
tissue damage due to inflammation mediated by increased sensitivity
of nociceptive-specific neurons, is a feature of a large number of
painful conditions for which no satisfactory treatment has been
available yet. The aim of this study was to assess the possible
analgesic affects of opiorphin, an endogenous enkephalinase
inhibitior, and noradrenalin, known to be involved in the intrinsic
modulation of nociceptive transmission, on inflammatory pain in rats.
Timing the delay for the first hind paw lift to a focused thermal
radiant heat, in vivo nociceptive behavioral "plantar test" was used for
assessing pain sensitivity of adult male Spraque Dawley rats. After
obtaining control nociceptive latency values, chronic inflammatory
pain was induced by intraplantar injection of zymosan (6 mg in 200
uL) and heat stimulated nociceptive tests were repeated. Pain
threshold values were determined and analyzed by a pairwise
comparison between vehicle and each opiorphin treated group using a
Dunnett's t-test on the ranked data. Zymosan caused a persistent
significant increase in pain sensitivity as measured 15-180 minutes
after its intraplantar injection (P <0.05). Systemic administration of
opiorphin (0.1-0.3 mg/kg) provided a dose dependent (P >0.05 for 0.1
mg/kg opiorphin while P <0.05 for 0.3 mg/kg i.p opiorfin at 30 and
40th min) inhibition of inflammatory pain. Combination of opiorphin
with noradrenalin (1 mg/kg) provided a limited synergic action, and
this effect was reversible by alpha-1 adrenergic blockage (prazosin 1
mg/kg). Results from this study provides some degree of overlap
between endogenous enkephalinergic and noradrenergic analgesic
modification which implicates potential for development of
therapeutical strategies involving combined use of enkephalinase
inhibitors and noradrenergic agonists for the management of persistent
pain associated with inflammatory painful conditions.