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TRPV1 channel inhibition contributes to the antinociceptive effects of Croton macrostachyus extract in mice.

Nguelefack TB, Dutra RC, Paszcuk AF, de Andrade EL, Calixto JB - BMC Complement Altern Med (2015)

Bottom Line: MECM also significantly and time dependently inhibited the capsaicin-induced nociception.These effects were not affected by glibenclamide or by rimonabant.The mechanism underlying the long lasting MECM antihyperalgesic effect is currently unknown, but might be mediated, at least partially, through the modulation of TRPV1 receptors.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Animal Physiology and Phytopharmacology, Department of Animal Biology, Faculty of Sciences, University of Dschang, P.O. Box 67, Dschang, Cameroon. nguelefack@yahoo.fr.

ABSTRACT

Background: Previous study showed that extracts from Croton macrostachyus (Euphorbiaceae) exhibit analgesic effects in acute pain models. The present study evaluates the antinociceptive properties of the methanol/methylene chloride extract (MECM) of the stem bark of this plant using mice models of persistent inflammatory and neuropathic pain, and assesses its mechanism of action.

Methods: MECM was tested on Complete Freund adjuvant (CFA)-induced persistent thermal and mechanical pain, neuropathic pain induced by partial sciatic nerve ligation (PSNL), prostaglandin E2 (PGE2)-induced acute mechanical hyperalgesia, as well as on nociception induced by capsaicin in mice. Mechanical hyperalgesia was assessed using von Frey hair in awake mice. The mechanism of action of MECM was evaluated by using glibenclamide on PGE2-induced hyperalgesia or rimonabant on capsaicin-induced pain.

Results: MECM administered orally at the doses of 250 and 500 mg/kg, induced long lasting and significant antihyperalgesic effects on CFA-inflammatory and PSNL-induced neuropathic pain. MECM significantly reduced the mechanical hyperalgesia induced by PGE2 either when administered preventively or therapeutically. MECM also significantly and time dependently inhibited the capsaicin-induced nociception. These effects were not affected by glibenclamide or by rimonabant.

Conclusions: The present results demonstrate that the oral administration of MECM to mice resulted in long lasting antihyperalgesic activity in inflammatory and neuropathic pain as well as in acute and persistent pain. The mechanism underlying the long lasting MECM antihyperalgesic effect is currently unknown, but might be mediated, at least partially, through the modulation of TRPV1 receptors.

No MeSH data available.


Related in: MedlinePlus

Effect of oral administration of the methanol/methylene chloride extract of the stem bark of Croton macrostachyus (MECM) on the mechanical hyperalgesia evaluated with von Frey hair (0.4 g) in PGE2 (0.1 nmol/paw) inflamed mice paw. In panel (a), animals were treated 1 hour before PGE2 injection and pain response was evaluated before treatment and after PGE2 injection. In panel (b) and (c), treatments were given orally 1 hour after PGE2 and response to pain was evaluated before PGE2 injection and after treatment. N = 5; ap < 0.05; bp < 0.01; cp < 0.001 significantly different compared to vehicle. B = basal response to mechanical stimulation
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Fig3: Effect of oral administration of the methanol/methylene chloride extract of the stem bark of Croton macrostachyus (MECM) on the mechanical hyperalgesia evaluated with von Frey hair (0.4 g) in PGE2 (0.1 nmol/paw) inflamed mice paw. In panel (a), animals were treated 1 hour before PGE2 injection and pain response was evaluated before treatment and after PGE2 injection. In panel (b) and (c), treatments were given orally 1 hour after PGE2 and response to pain was evaluated before PGE2 injection and after treatment. N = 5; ap < 0.05; bp < 0.01; cp < 0.001 significantly different compared to vehicle. B = basal response to mechanical stimulation

Mentions: Intraplantar injection of PGE2 resulted in a significant (p < 0.01) hyperalgesia to mechanical stimulation when assessed by von Frey hair. PGE2–induced hyperalgesia was significantly reduced by dipyrone (120 mg/kg, p.o.) and by MECM (500 mg/kg, p.o.) when both were given as preventive treatment (Fig. 3a). As shown in Fig. 3b, both substances significantly inhibited PGE2-induced hyperalgesia when administered as a therapeutic scheme of treatment. However, glibenclamide significantly reduced the antihyperalgesic effect of dipyrone but failed to prevent that of MECM although an effect was observed at the 4th hour (Fig. 3c).Fig. 3


TRPV1 channel inhibition contributes to the antinociceptive effects of Croton macrostachyus extract in mice.

Nguelefack TB, Dutra RC, Paszcuk AF, de Andrade EL, Calixto JB - BMC Complement Altern Med (2015)

Effect of oral administration of the methanol/methylene chloride extract of the stem bark of Croton macrostachyus (MECM) on the mechanical hyperalgesia evaluated with von Frey hair (0.4 g) in PGE2 (0.1 nmol/paw) inflamed mice paw. In panel (a), animals were treated 1 hour before PGE2 injection and pain response was evaluated before treatment and after PGE2 injection. In panel (b) and (c), treatments were given orally 1 hour after PGE2 and response to pain was evaluated before PGE2 injection and after treatment. N = 5; ap < 0.05; bp < 0.01; cp < 0.001 significantly different compared to vehicle. B = basal response to mechanical stimulation
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4548910&req=5

Fig3: Effect of oral administration of the methanol/methylene chloride extract of the stem bark of Croton macrostachyus (MECM) on the mechanical hyperalgesia evaluated with von Frey hair (0.4 g) in PGE2 (0.1 nmol/paw) inflamed mice paw. In panel (a), animals were treated 1 hour before PGE2 injection and pain response was evaluated before treatment and after PGE2 injection. In panel (b) and (c), treatments were given orally 1 hour after PGE2 and response to pain was evaluated before PGE2 injection and after treatment. N = 5; ap < 0.05; bp < 0.01; cp < 0.001 significantly different compared to vehicle. B = basal response to mechanical stimulation
Mentions: Intraplantar injection of PGE2 resulted in a significant (p < 0.01) hyperalgesia to mechanical stimulation when assessed by von Frey hair. PGE2–induced hyperalgesia was significantly reduced by dipyrone (120 mg/kg, p.o.) and by MECM (500 mg/kg, p.o.) when both were given as preventive treatment (Fig. 3a). As shown in Fig. 3b, both substances significantly inhibited PGE2-induced hyperalgesia when administered as a therapeutic scheme of treatment. However, glibenclamide significantly reduced the antihyperalgesic effect of dipyrone but failed to prevent that of MECM although an effect was observed at the 4th hour (Fig. 3c).Fig. 3

Bottom Line: MECM also significantly and time dependently inhibited the capsaicin-induced nociception.These effects were not affected by glibenclamide or by rimonabant.The mechanism underlying the long lasting MECM antihyperalgesic effect is currently unknown, but might be mediated, at least partially, through the modulation of TRPV1 receptors.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Animal Physiology and Phytopharmacology, Department of Animal Biology, Faculty of Sciences, University of Dschang, P.O. Box 67, Dschang, Cameroon. nguelefack@yahoo.fr.

ABSTRACT

Background: Previous study showed that extracts from Croton macrostachyus (Euphorbiaceae) exhibit analgesic effects in acute pain models. The present study evaluates the antinociceptive properties of the methanol/methylene chloride extract (MECM) of the stem bark of this plant using mice models of persistent inflammatory and neuropathic pain, and assesses its mechanism of action.

Methods: MECM was tested on Complete Freund adjuvant (CFA)-induced persistent thermal and mechanical pain, neuropathic pain induced by partial sciatic nerve ligation (PSNL), prostaglandin E2 (PGE2)-induced acute mechanical hyperalgesia, as well as on nociception induced by capsaicin in mice. Mechanical hyperalgesia was assessed using von Frey hair in awake mice. The mechanism of action of MECM was evaluated by using glibenclamide on PGE2-induced hyperalgesia or rimonabant on capsaicin-induced pain.

Results: MECM administered orally at the doses of 250 and 500 mg/kg, induced long lasting and significant antihyperalgesic effects on CFA-inflammatory and PSNL-induced neuropathic pain. MECM significantly reduced the mechanical hyperalgesia induced by PGE2 either when administered preventively or therapeutically. MECM also significantly and time dependently inhibited the capsaicin-induced nociception. These effects were not affected by glibenclamide or by rimonabant.

Conclusions: The present results demonstrate that the oral administration of MECM to mice resulted in long lasting antihyperalgesic activity in inflammatory and neuropathic pain as well as in acute and persistent pain. The mechanism underlying the long lasting MECM antihyperalgesic effect is currently unknown, but might be mediated, at least partially, through the modulation of TRPV1 receptors.

No MeSH data available.


Related in: MedlinePlus