Evaluation of opioid‐induced antinociceptive effects in anaesthetized and conscious animals

Clark, Stephen J.; Follenfant, R.L.; Smith, T.W.

doi:10.1111/j.1476-5381.1988.tb16574.x

Cited by 23 publications

(6 citation statements)

References 36 publications

(57 reference statements)

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“…The roles of opioid receptors in the regulation of modulation of nociceptive processing have been demonstrated in many previous studies [49, 50]. However, the effectiveness of opioid analgesics (such as morphine) has been overshadowed by many adverse side effects (e.g.…”

Section: Discussionmentioning

confidence: 99%

Antinociception of petroleum ether fraction derived from crude methanol extract of Melastoma malabathricum leaves and its possible mechanisms of action in animal models

Zakaria

Jaios

Omar

et al. 2016

BMC Complement Altern Med

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Background Melastoma malabathricum L. (family Melastomaceae) has been traditionally used as remedies against various ailments including those related to pain. The methanol extract of M. malabathricum leaves has been proven to show antinociceptive activity. Thus, the present study aimed to determine the most effective fraction among the petroleum ether- (PEMM), ethyl acetate- (EAMM) and aqueous- (AQMM) fractions obtained through successive fractionation of crude, dried methanol extract of M. malabathricum (MEMM) and to elucidate the possible mechanisms of antinociception involved.MethodsThe effectiveness of fractions (100, 250 and 500 mg/kg; orally) were determine using the acetic acid-induced abdominal constriction test and the most effective extract was further subjected to the hot plate- or formalin-induced paw licking-test to establish its antinociceptive profile. Further elucidation of the role of opioid and vanilloid receptors, glutamatergic system, and nitric oxide/cyclic guanosine phosphate (NO/cGMP) pathway was also performed using the appropriate nociceptive models while the phytoconstituents analyses were performed using the phytochemical screening test and, HPLC-ESI and GCMS analyses.ResultsPEMM, EAMM and AQMM significantly (p < 0.05) attenuated acetic acid-induced nociception with the recorded EC50 of 119.5, 125.9 and 352.6 mg/kg. Based on the EC50 value, PEMM was further studied and also exerted significant (p < 0.05) antinociception against the hot plate- and formalin-induced paw licking-test. With regards to the mechanisms of antinociception,: i) PEMM significantly (p < 0.05) attenuated the nociceptive action in capsaicin- and glutamate-induced paw licking test.; ii) naloxone (5 mg/kg), a non-selective opioid antagonist, failed to significantly (p < 0.05) inhibit PEMM’s antinociception iii) L-arginine (a nitric oxide precursor), but not NG-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase), methylene blue (MB; an inhibitor of cGMP), or their respective combination, significantly (p < 0.05) reversed the antinociception of PEMM. Phytochemical analyses revealed the presence of several antinociceptive-bearing bioactive compounds, such as triterpenes and volatile compounds like oleoamide and palmitic acid. The presence of low flavonoids, such as gallocatechin and epigallocatechin, saponins and tannins in PEMM might synergistically contribute to enhance the major compounds antinociceptive effect.ConclusionPEMM exerted a non-opioid-mediated antinociceptive activity at the central and peripheral levels via the inhibition of vanilloid receptors and glutamatergic system, and the activation of NO-mediated/cGMP-independent pathway. Triterpenes, as well as volatile oleoamide and palmitic acid, might be responsible for the observed antinociceptive activity of PEMM.

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Section: Discussionmentioning

confidence: 99%

Antinociception of petroleum ether fraction derived from crude methanol extract of Melastoma malabathricum leaves and its possible mechanisms of action in animal models

Zakaria

Jaios

Omar

et al. 2016

BMC Complement Altern Med

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show abstract

“…A modification (Clark et al, 1988) of the method originally described by Pizziketti et al (1985) was employed. Rats were closely restrained in a wire mesh cage and the lower half of their tails dipped in a beaker of cold water (0-1 • C).…”

Section: Tail Flick Assaymentioning

confidence: 99%

The analgesic effect of the methanolic extract of Acanthus montanus

Adeyemi

Okpo

Okpaka

2004

Journal of Ethnopharmacology

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“…This may reflect effects of the different routes of administration of the K-agonist. Clark et al (1988) found that U50,488 administered i.v. to urethane-anaesthetized rats resulted in large fall in blood pressure, 27mmHg at 0.79mgkg-1 and 36mmHg at 7.9mgkg-.…”

Section: Discussionmentioning

confidence: 99%

κ‐Opioid‐receptor agonists modulate the renal excretion of water and electrolytes in anaesthetized rats

Ashton

Balment

Blackburn³

1990

British J Pharmacology

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1 Subcutaneous injection of the K-opioid agonists U50,488 (10mgkg-') and tifluadom (3.5mgkg-1) into Inactin-anaesthetized, saline-infused rats was associated with a diuresis, antinatriuresis and antikaliuresis which lasted for up to 2h. A high (5mgkg-1), but not low (0.1mgkg-1), dose of naloxone blocked the renal effects of U50,488. 2 U50,488 administration in anaesthetized, vasopressin-deficient Brattleboro DI rats was associated with an attenuated diuresis, though the antinatriuretic response remained intact. 3 The diuretic action of U50,488 was associated with an increase in glomerular filtration rate while fractional fluid reabsorption remained steady. In contrast, fractional sodium and potassium reabsorption were increased. 4 These data suggest that K-Opioid agonists alter renal handling of both water and electrolytes. This appears to be mediated by two separate mechanisms: increased fluid loss largely reflects altered glomerular events while the fall in electrolyte excretion results from altered tubular handling.

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Evaluation of opioid‐induced antinociceptive effects in anaesthetized and conscious animals

Cited by 23 publications

References 36 publications

Antinociception of petroleum ether fraction derived from crude methanol extract of Melastoma malabathricum leaves and its possible mechanisms of action in animal models

Antinociception of petroleum ether fraction derived from crude methanol extract of Melastoma malabathricum leaves and its possible mechanisms of action in animal models

The analgesic effect of the methanolic extract of Acanthus montanus

κ‐Opioid‐receptor agonists modulate the renal excretion of water and electrolytes in anaesthetized rats

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