TRPA1 involvement in analgesia induced by Tabernaemontana catharinensis ethyl acetate fraction in mice.
Phytomedicine
; 54: 248-258, 2019 Feb 15.
Article
en En
| MEDLINE
| ID: mdl-30668375
BACKGROUND: Ionic channels such as the transient receptor potential ankyrin 1 (TRPA1) are essential for the detection and transmission of painful stimuli. In this sense, new TRPA1 antagonists have been searched as analgesics. PURPOSE: Preclinical studies support the antinociceptive activity of Tabernaemontana catharinensis ethyl acetate fraction (Eta), which has constituents previously identified as TRPA1 antagonists (gallic acid). It was verified for the first time the involvement of the TRPA1 on Eta's antinociceptive and anti-inflammatory effects in mice pain models. STUDY DESIGN: It was evaluated the Eta's effect (0.01-100â¯mg/kg, oral route) on nociceptive (spontaneous nociception, mechanical and cold allodynia) and inflammatory (paw edema) parameters in pain models involved with TRPA1 activation. METHODS: Firstly, it was investigated the ability of Eta to act on TRPA1 or TRPV1 channels (Ca2+influx and binding assays in mice spinal cords). Next, it was evaluated the Eta's antinociceptive and anti-inflammatory effects after intraplantar injection of TRPA1 agonists (hydrogen peroxide, cinnamaldehyde or allyl isothiocyanate) in male Swiss mice (30-35â¯g). Moreover, the Eta's antinociceptive effects were evaluated on complete Freund's adjuvant (CFA)-induced chronic inflammatory pain (CIP), postoperative pain and on paclitaxel-induced peripheral neuropathy (PIPN). Oxidative parameters were evaluated in mice paw utilized for CFA induced-CIP model. RESULTS: Eta inhibited the TRPA1 agonist-induced Ca2+ influx [Imaxâ¯=â¯72.4⯱â¯1.5%; IC50â¯=â¯0.023(0.004-0.125)µg/ml], but not TRPV1 agonist-induced, nor was able to displace [3H]-resiniferatoxin (TRPV1 agonist) binding. Eta (0.1-100â¯mg/kg) inhibited the spontaneous nociception [ID50â¯=â¯0.043(0.002-0.723)mg/kg], mechanical [ID50â¯=â¯7.417(1.426-38.570)mg/kg] and cold allodynia, and edema development caused by TRPA1 agonists. Moreover, Eta (100â¯mg/kg) prevented and reversed the CFA-induced CIP (Imaxâ¯=â¯55.8⯱â¯13.7%, Imaxâ¯=â¯80.4⯱â¯5.1%, respectively) and postoperative pain (Imaxâ¯=â¯88.0⯱â¯11.6%, Imaxâ¯=â¯51.3⯱â¯14.9%, respectively), been also effective in reversing the acute (Imaxâ¯=â¯94.4⯱â¯12.4%) and chronic (Imaxâ¯=â¯86.8⯱â¯8.6%) PIPN. These effects seem to occur by TRPA1 channels pathway, and independently of TRPV1 or oxidative mechanisms. CONCLUSION: Our results demonstrate that Eta-induced antinociception and anti-inflammatory effects occur by TRPA1 inhibition making possible the use of this preparation as a potential therapeutic agent to treat pathological pains.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Extractos Vegetales
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Tabernaemontana
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Canal Catiónico TRPA1
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Hiperalgesia
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Analgésicos
/
Acetatos
Límite:
Animals
Idioma:
En
Revista:
Phytomedicine
Asunto de la revista:
TERAPIAS COMPLEMENTARES
Año:
2019
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Alemania