Naslov
Selective mu-opioid receptor antagonist naloxonazine reverses bilateral antinociceptive effect of botulinum toxin type A in a rat model of "mirror" pain

Autori
Drinovac, Višnja ; Bach-Rojecky, Lidija ; Lacković, Zdravko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Special Issue: Abstracts of the 17th World Congress of Basic and Clinical Pharmacology, 13–18 July 2014, Cape Town, South Africa, Basic and Clinical Pharmacology & Toxicology / - Cape Town : John Wiley & Sons, 2014, 212-212

Skup
17th World Congress of Basic and Clinical Pharmacology

Mjesto i datum
Cape Town, Južnoafrička Republika, 13.06.2014. - 18.06.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
bilateral pain; botulinum toxin type A; selective mu-opioid antagonist

Sažetak
Background: Antinociceptive effect of botulinum toxin type A (BTXA)is demonstrated in various types of pain, both in animals and humans. According to preclinical behavioral results, mainly from our laboratory, BTX-A alleviates pain by acting within CNS, but the mechanism of its central action is poorly understood. Recently we discovered that non-selective and selective mu- opioid antagonists reverse the antinociceptive effect of BTX-A in different types of pain – acute inflammatory and neuropathic pain, thus concluding the involvement of endogenous opioid system in the antinociceptive effect of BTX-A. The objective of the present research was to investigate the effects of selective mu-opioid antagonist naloxonazine in a model of bilateral chronic inflammatory muscle pain. Methods: 100 ll of 3% carrageenan (dissolved in saline) or saline was injected into right gastrocnemius muscle of male Wistar rats. Animals which developed bilateral mechanical allodynia (tested with von Frey filaments) 2 weeks following carrageenan injection were divided into following groups (5–6 animals per experimental group): (1) saline (intraplantarly, into the hind-paw pad), (2) BTX-A (5 U/kg ; intraplantarly), (3) and (4) saline or BTX-A + naloxonazine (1.5 ug/10 ul, intrathecally), (5) and (6) saline or BTX-A + naloxonazine (1.5 ug/5 ul intracerebroventriculary). BTX-A was injected 5 days and naloxonazine 24 h before nociceptive testing. Results: Unilaterally injected BTX-A decreased mechanical hypersensitivity not only on ipsilateral (P < 0.001), but on the contralateral side as well (P < 0.001). Intrathecal, low dose of selective mu-opioid antagonist abolished the bilateral antinociceptive effect in BTX-A treated animals (P < 0.001), while the same dose applied into cerebral ventricles had no effect on BTX-A antinociceptive action. Naloxonazine alone had no effect on carragenaan induced bilateral allodynia. Conclusions: Unilaterally injected BTX-A has bilateral antinociceptive effect in carrageenan induced bilateral pain that can be prevented by opioid antagonist naloxonazine. This observation suggests the involvement of central endogenous opioid system in bilateral antinociceptive effect of BTX-A, most probably at spinal level.

Izvorni jezik
Engleski

Znanstvena područja
Biologija, Temeljne medicinske znanosti, Farmacija

POVEZANOST RADA