Acetic Acid-induced Writhing Tests Research Articles

Analgesic and Antioxidant Activity of Mangiferin and Its Derivatives: the Structure Activity Relationship

Mangiferin, 2-beta-D-glucopyranosyl-1,3,6,7-tetrahydroxy-9H-xanthen-9-one, obtained directly from methanolic extracts of Bombax ceiba leaves in substantial amounts demonstrated strong antioxidant activity (EC(50) 5.8+/-0.96 mug/ml or 13.74 muM) using DPPH assay comparable to rutin, commonly used as antioxidant for medical purposes. The acetyl and cinnamoyl derivatives were found to be less active than mangiferin whereas, methyl and 3,6,7-trimethylether tetraacetate derivatives were inactive implying that for antioxidant activity, free hydroxyl groups and catechol moiety are essential. Moreover, mangiferin showed hepatoprotective activity against carbon tetrachloride induced liver injury further supporting the free radical scavenging property in the in vivo system. Additionally, plant extracts and mangiferin failed to exhibit acute anti-inflammatory activity whereas, it displayed significant analgesic effect in acetic acid-induced writhing and hot plate tests in mice. Using naloxone, it was revealed that plant extracts induced analgesia was independent of opioid receptor, whereas, mangiferin demonstrated significant interaction with it at peripheral site with a slight contribution at the neuronal level.

Role of the histamine system in nefopam-induced antinociception in mice

The present study explored the role of the histaminergic system in nefopam analgesia based on the structural relationship between nefopam and diphenhydramine. In vitro binding assays revealed that nefopam possesses moderate affinity for histamine H 1 and H 2 receptor subtypes, with IC 50 of 0.8 and 6.9 μM, respectively, but no affinity for histamine H 3 receptor subtype until 100 μM. Subcutaneous nefopam administration dose-dependently inhibited pain in acetic acid-induced writhing (1–30 mg/kg) and formalin (1–10 mg/kg) tests in the mouse. Pretreatment with the histamine-depleting agent α-fluoromethylhistidine (α-FMH, 50 mg/kg), the histamine H 1 receptor antagonist pyrilamine (3 or 10 mg/kg), or the histamine H 2 receptor antagonists cimetidine (100 mg/kg) and zolantidine (10 or 30 mg/kg) did not significantly modify nefopam antinociception in both tests. The histamine H 3 receptor agonist R(−)α-methylhistamine (RAMH, 10 mg/kg) did not significantly modify the nefopam analgesic activity in the writhing test. At 25 mg/kg, RAMH inhibited nefopam antinociception at 3 mg/kg, but not at 10 mg/kg in the formalin test. However, pretreatment with the histamine H 3 receptor antagonist thioperamide (25 mg/kg) inhibited nefopam antinociception in the writhing test, but not in the formalin test. In conclusion, nefopam analgesic activity is not mediated by histamine H 1 or H 2 receptors, but can be slightly modulated by histamine H 3 receptors in mouse pain tests.

The antinociceptive effect of some Egyptian medicinal plant extracts

The antinociceptive effect of methanolic extracts (200 and 400 mg kg −1) of eight Egyptian medicinal plants was studied using acetic acid-induced writhing and tail-flick test in mice. Oral administration of 400 mg kg −1 methanolic extracts of Convolvulus fatmensis, Alhagi maurorum, Plantago major seeds, Conyza dioscaridis significantly ( P < 0.05) inhibited the nociception to acetic acid-induced writhes with a protection of 85.5–61.3%. Schouwia thebaica, Diplotaxis acris, Plantago major leaves and Mentha microphylla, in the large dose, showed a protection of 50.8–45.8%, which were significantly different as compared to control. The smaller dose of the tested plant extracts did not protect animals from painful acetic acid stimulation with the exception of Alhagi maurorum. In the tail-flick test, methanolic extracts of Mentha microphylla, Conyza dioscaridis, Alhagi maurorum, Plantago major leaves, Diplotaxis acris and Convolvulus fatmensis in a dose of 400 mg kg −1 produced significant increase in the latency to response of tail to thermal stimulation. Mild or no effect was observed by the small dose with the exception of Diplotaxis acris that had significant antinociceptive effect at the dose of 200 mg kg −1. The extracts of all tested plants in doses up to 2 g kg −1 b.wt. did not cause any deaths or major signs of acute toxicity. Phytochemical screening indicated the presence of unsaturated sterols, triterpenes, tannins, flavonoids and carbohydrates and/or glycosides as major constituents.

Black cumin seed essential oil, as a potent analgesic and antiinflammatory drug.

The steam-distilled essential oil of Iranian black cumin seed (Nigella sativa L.) was investigated for its composition and analgesic and antiinflammatory properties. After oil analysis by GC/MS, 20 compounds were identified in the oil, obtained in 0.4% (v/w) yield. Among them, para-cymene (37.3%) and thymoquinone (13.7%) were the major components. Acetic acid-induced writhing, formalin and light tail flick tests were used for assessment of analgesic activity. Antiinflammatory activity was evaluated using carrageenan-induced paw oedema in rats and croton oil-induced ear oedema in mice. Black cumin seed essential oil (BCSEO) was found to produce a significant analgesic effect in acetic acid-induced writhing, formalin and light tail flick tests. Naloxone, an opioid antagonist, could not reverse the analgesic effect observed in the formalin test. Although oral administration of BCSEO at doses of 100, 200 and 400 micro L/kg did not exert a significant antiinflammatory effect in the carrageenan test, i.p. injection of the same doses significantly (p < 0.001) inhibited carrageenan-induced paw oedema. BCSEO at doses of 10 and 20 micro L/ear could also reduce croton oil-induced oedema. It seems that mechanism(s) other than opioid receptors is (are) involved in the analgesic effect of BCSEO since naloxone could not reverse this effect. Both systemic and local administration of BCSEO showed antiinflammatory activity. Thymoquinone, as one of the major components of BCSEO, probably has an important role in these pharmacological effects.

Evaluation of Antioxidant, Anti-inflammatory, and Antinociceptive Properties of Aerial Parts of Vicia sativa and its Flavonoids

Objective: In this study, we aimed to identify the minor flavonoids of the areal parts of Vicia sativa , a biologically active plant growing in El-Hassana, North Sinai, Egypt, and to monitor the antioxidant, anti-inflammatory, and antinociceptive activities of the plant extract and its purified flavonoids. Methods: antioxiant activity of V. sativa was assessed by four different assays including DPPH assay, quenching of ROO radicals, respiratory burst in rat neutrophils, and lipid peroxidation. On the other hand, antiinflammatory and antinociceptive effects of V. sativa and its flavonoids were assessed by carrageenaninduced inflammation in mice, acetic acid-induced writhing and formalin-licking test. Results: Nine flavonoids were isolated from the ethanol extract of the aerial parts of V. sativa and identified as active components: apigenin 4'-O-β-D-glucopyranoside [1], apigenin 6,8-di-C-β-D-glucopyranoside [2], apigenin 6-C-α-L-arabinopyranoside-8-C-β-D-glucopyranoside [3], kaempferol-3-O-β-Ldirhamnopyranosyl (1→2, 1→6)- β-D-glucopyranoside [4], kaempferol 3-O-(4-β-D-xylopyranosyl)-α-L-rhamnopyranoside-7-O-L-rhamnopyranoside [5], kaempferol-3-O- α-L-rhamnopyranosyl (1→6)- β-D-glucopyranoside [6], Luteolin-7-O- β-D-glucopyranoside [7] quercetin 3-O-β-glucopyranoside [8], and quercetin 3,7 di-O- glucopyranoside [9]. Our findings indicated a potent antioxidant activity of V. sativa extract against different radicals (DPPH, superoxide anion, and peroxyl) and an inhibitory activity against carbon tetrachloride-induced lipid peroxidation. compound 6 showed effective inhibitory activity of both peroxyl radicals; compounds 1, 2, 3, 6, 8 and 9 decreased both superoxide anion radical production in PMA-stimulated neutrophil, and compounds 2, 3, 5, and 7 were dramatically effective in inhibition of CCl 4 -induced lipid peroxidation. Additionally, our results revealed that V. sativa extract exhibited inhibitory activity against different inflammatory and nociceptive chemical agents. The purified flavonoids generally showed low anti-inflammatory and antinociceptive activities in a range of 0.9-18.3 % of inhibition, whereas compounds 1, 3, 4, and 8 were the most effective flavonoids. Structure-activity correlation was also discussed. Conclusion: V. sativa extract possessed antioxidant, anti-inflammatory, and antinociceptive activities to variable extents, which may be attributed to the radical scavenging and anti-inflammatory activity of some of its flavonoid constituents. These activities may help in prevention and/or treatment of the pathological disorders in which free radical oxidation, inflammation, and cellular activation are suggested to play a fundamental pathogenic role.

Antinociceptive and hypnotic effects of Premna tomentosa L. (Verbenaceae) in experimental animals

Medicinal plants are believed to be an important source of new chemical substances with potential therapeutic effects. The research into plants with alleged folklore use as pain relievers should therefore be viewed as a fruitful and logical research strategy in the search of new analgesic drugs. In the present inquiry, antinociceptive effects of Premna tomentosa (PT) leaf extract (in methanol) were explored in experimental animals by acetic acid-induced writhing, tail flick and tail clip tests. Oral administration of PT extract at different doses (100, 200, 400 and 500 mg/kg) led to significant antinociceptive effects. The extract was also tested for hypnotic effects. Treatment with extracts at different doses (100, 200, 400 and 500 mg/kg) decreased the locomotor activity and potentiated the pentobarbitone-induced sleep time. The responses were dose-dependent. On the basis of the present finding, we can conclude that PT possesses antinociceptive and hypnotic activities.

Evaluation of the analgesic activity of extracts of Miconia rubiginosa (Melastomataceae).

The analgesic effects of the hexane, methylene chloride and ethanol extracts of Miconia rubiginosa were evaluated in mice and rats using the acetic acid-induced writhing and hot plate tests. The extracts (100, 200 and 300 mg/kg body wt.) and indomethacin (5 mg/kg body wt.) produced a significant (p < 0.05 and p < 0.01) inhibition of acetic acid-induced abdominal writhing. These same extracts (200 mg/kg body wt.) showed a significant (p < 0.05) antinociceptive effect, lower than that produced by morphine (4 mg/kg body wt.). The fractionation of the methylene chloride extract yielded ursolic and oleanoic acids as the major compounds. Using only gas chromatography, it was possible to identify the following triterpenes in the hexane extract: alpha-amyrin, beta-amyrin, lupeol and beta-sitosterol.

Anti-inflammatory and antinociceptive properties of dantrolene sodium in rats and mice

Our study aimed at examining the possible anti-inflammatory and antinociceptive effects of dantrolene sodium in rats and mice. The anti-inflammatory effect of dantrolene sodium (2.5, 5 and 10 mg kg −1) was investigated and compared with diclofenac sodium (5 mg kg −1) using the formalin-, histamine-, and carrageenan-induced paw oedema and cotton pellet granuloma tests. Analgesic effects of dantrolene sodium were evaluated and compared with metamizol (200 mg kg −1) in acetic acid-induced writhing and formalin-induced paw licking tests. It was found that dantrolene sodium significantly diminished the nociceptive response in mice, showing at the same time considerable anti-inflammatory properties in rats.

The involvement of nitric oxide in the analgesic effects of ketamine

We investigated the contribution of NO-cyclic GMP (cGMP) pathway to the antinociceptive effects of ketamine in mice by using the nitric oxide synthase inhibitor, nitro g- L-arginine methyl ester (L-NAME). Intraperitoneal (i.p.) (1, 5 or 10 mg/kg) or intrathecal (i.th.) (10, 30 or 60 μg/mouse) administration of ketamine produced dose-dependent antinociceptive effects in the acetic acid-induced writhing and formalin tests but not in the tail-flick nor in hot-plate tests. Pretreatment of mice with L-NAME (10 mg/kg, i.p.) which produced no antinociception on its own, significantly inhibited the antinociceptive effect of ketamine (1, 5 or 10 mg/kg, i.p.). However, L-NAME (30 μg/mouse) was given intrathecally, it neither modified the antinociceptive effect of i.th. ketamine (10, 30 or 60 μg/mouse) nor did it produce an antinociceptive effect alone. These data suggest that the activation of the NO-cGMP pathway probably at the supraspinal level, but not spinal level, contributes to the antinociceptive effects of ketamine.

On the antinociceptive effect of fluoxetine, a selective serotonin reuptake inhibitor

Antidepressant drugs are reported to be used as co-analgesics in clinical management of migraine and neuropathic pain. The mechanism through which they alleviate pain remains unknown. The present study explores the possible mechanism of a selective serotonin reuptake inhibitor (SSRI) fluoxetine-induced antinociception in animals. Acetic acid-induced writhing, hot plate and tail-flick test were used to assess fluoxetine-induced antinociception. Fluoxetine (5–20 mg kg −1, i.p.) produced a significant and dose-dependent antinociceptive effect against acetic acid-induced writhing in mice. Fluoxetine (20 mg kg −1) also exhibited antinociceptive effect in tail flick as well as hot plate assays. Further, i.c.v. administration of fluoxetine showed significant antinociception against writhing test in rats. However, fluoxetine (1 μg/10 μl/rat, i.c.v.) did not exhibit any antinociceptive effect in serotonin-depleted animals. Further, pindolol (10 mg kg −1, i.p.) enhanced fluoxetine-induced antinociceptive effect. The antinociceptive effect of fluoxetine was sensitive to blockade by naloxone (5 mg kg −1, i.p.) and naltrexone (5 mg kg −1, i.p.). These data suggest that fluoxetine-induced antinociception involves both central opioid and the serotoninergic pathways.

Gene therapy for the management of pain: part II: molecular targets.

TREATMENT of chronic pain, particularly of neuropathic etiology, is extremely difficult and resistant to many available pharmacologic therapies. Current analgesic agents may be limited with regard to analgesic efficacy or side effects. Newer and experimental pharmacologic agents may also have significant limitations. By targeting a specific receptor or other specific protein targets, a gene therapy approach to the treatment of pain may provide greater analgesic efficacy without the limitations associated with current pharmacotherapy. Advances in the field of gene therapy, along with significant increases in our understanding of the neurobiology of nociception and knowledge of the fundamental genetic structure of many nociceptive targets, have made gene therapy for the management of pain a conceivable reality. In part I of this review, we introduced the basic concepts of gene therapy with an emphasis on the available tools (e.g., viral vectors and antisense oligonucleotides) and strategies for upregulating antinociceptive or downregulating pronociceptive targets. In part II, we summarize current knowledge regarding the nociceptive role, molecular biology, and antisense and knockout data of several novel nociceptive targets for gene therapy. We base our selection of the targets included in this review on the three aforementioned criteria. The targets selected are the best characterized and, in our opinion, most likely amenable to the gene therapeutic approach. A simple but feasible strategy and potential gene therapy targets for the management of pain are summarized in figure 1. However, the list is admittedly incomplete, and the readers are referred to other recent reviews cited in part I of this review for a broader perspective on potential targets for the management of pain.

Antinociceptive activity of Zizyphus spina-christi root bark extract

The antinociceptive effect of the aqueous extract of Zizyphus spina-christi root bark was investigated in mice and rats. Acetic acid-induced writhing, formalin and thermal (hot plate) tests were used. The extract (50 and 100 mg/kg, i.p.) showed a dose-dependent analgesic effect in all the tests used. Its i.p. LD 50 in mice was 2236.07 mg/kg.

Effects of human placental extract on chemical and thermal nociception in mice

Several reports indicate that pregnancy and parturition are associated with elevated maternal pain thresholds to noxious stimuli. The objective of this study was to examine whether the human placental extract, a clinically used preparation, can inhibit experimental nociception. Nociception was assessed in mice using acetic acid-induced writhing and hot-plate tests. The human placental extract (200 and 400 mg/kg, i.p.) elicited dose-related antinociception in the acetic acid-induced writhing test. Furthermore, it (200 mg/kg, i.p.) potentiated the morphine-induced antinociception (1.25 mg/kg, s.c.). In the hot-plate test, the human placental extract (100, 200 and 400 mg/kg, i.p.) per se, displayed no significant antinociception but potentiated the duration of morphine (10 mg/kg, s.c.) analgesia. The potentiation by the extract of the morphine-induced antinociception in both acetic acid and hot-plate tests was, however, found to be naloxone sensitive. Mice treated with the extract (400 mg/kg, i.p.) neither manifested any overt behavioural change in the open-field test nor demonstrated significant influence on pentobarbital sleeping time, suggesting that it has no central depressant or sedative activity. The data provide evidence to show that the human placental extract has a peripheral analgesic property possibly mediated by an opioid mechanism.

Analgesic Effect Of Dioclenol And Dioflorin Isolated From Dioclea Grandiflora

The analgesic activity of dioflorin and dioclenol, two constituents of Dioclea grandiflora Mart., has been studied in mice. It was found that dioclenol (10 mg/kg, i.p.) and dioclenol (10 mg/kg, i.p.) were effective in the acetic acid-induced writhing and tail immersion tests. These observations suggest that dioflorin and dio-clenol possesses central antinociceptive activity.

Effects of Intrathecally Administered Aminoglycoside Antibiotics, Calcium-Channel Blockers, Nickel and Calcium on Acetic Acid-Induced Writhing Test in Mice

1. Antinociceptive effects of intrathecally administered aminoglycoside antibiotics, calcium-channel blockers, nickel and calcium ions on the acetic acid–induced writhing test in mice were examined. 2. Neomycin (0.5–20.0 μg/mouse) gentamicin (5–40 μg/mouse), nicardipine, diltiazem and verapamil (0.5–80.0 μg/mouse) and calcium ions (0.02–1.0 μmol/mouse) exerted a dose-dependent antinociceptive activity on the acetic acid–induced writhing test. Nickel ions ( 2.5, 5.0 and 10.0 μmol/mouse) were found ineffective in this test. 3. These results suggest that N- and L-type, but not T-type, voltage-dependent calcium channels are implicated in the spinal processing of nociceptive information.

Anti-nociceptive and anti-inflammatory effects of some Jordanian medicinal plant extracts

The anti-nociceptive effect of ethanolic extract of 11 traditionally used Jordanian plants was studied by using the acetic acid-induced writhing and hot-plate test in mice. The anti-inflammatory effect of these plants was determined by xylene-induced ear oedema in mice and cotton pellet granuloma test in rats. Mentha piperita, Cinnamomum zeylanicum, Apium graveolens, Eucalyptus camaldulentis, and Ruta graveolens possess an anti-nociceptive effect against both acetic acid-induced writhing and hot plate-induced thermal stimulation. M. piperita, Jasminum officinale, Commiphora molmol, and Beta vulgaris possess an anti-inflammatory effect against acute (xylene-induced ear oedema) and chronic (cotton-pellet granuloma) inflammation. The anti-nociceptive and anti-inflammatory effects were dose dependent. These data affirm the traditional use of some of these plants for painful and inflammatory conditions.

Pharmacologically active components of Todopon Puok (Fagraea racemosa), a medicinal plant from Borneo.

The lignans of (+)-pinoresinol, (+)-epipinoresinol, (+)-lariciresinol and (+)-isolariciresinol together with phenols such as syringaldehyde and 7,8-dihydro-7-oxy-coniferyl alcohol were isolated from Todopon Puok (Fagraea racemosa Jack ex Wall), a medicinal plant from Borneo, using a bioassay of the relaxation effect on norepinephrine (NE)-induced contraction in rat aortic strips. The plant extract also exhibited analgesic properties in the acetic acid-induced writhing and tail pressure tests in mice, with the activity being concentrated in the lignan fraction. (+)-Pinoresinol showed analgesic effect on writhing symptoms in mice which were dose-dependent, and produced local anesthesia in guinea pigs.

Inhibitory effects of quercetin and other flavonoids on electrically-induced contractions of guinea pig isolated ileum

Millettia peguensis, popular for its ethnopharmacological uses, was employed to evaluate its different pharmacological properties in this study. The analgesic studies of the plant have been performed by acetic acid-induced writhing and formalin-induced licking tests respectively, whereas the antidiarrheal experiment was done by castor oil-induced diarrheal test. Besides, antioxidant, cytotoxic, antimicrobial, thrombolytic evaluations were performed by DPPH scavenging with phenol content determination, brine shrimp lethality, disc diffusion and clot lysis methods respectively. Moreover, in silico study of the phytoconstituents was carried out by molecular docking and ADME/T analysis.The methanol extract of Millettia peguensis (MEMP) revealed significant biological activity in the analgesic and antidiarrheal test (p < 0.001) compared to the standards. Antioxidant assay displayed promising IC50 values (15.96 μg/mL) with the total phenol content (65.27 ± 1.24 mg GAE/g). In the cytotoxicity study, the LC50 value was found to be 1.094 μg/mL. Besides, MEMP was highly sensitive to the bacteria but less liable to clot lysis. Furthermore, phytoconstituents exposed potential binding affinity towards the selected receptors, whereas the ADME/T properties indicated the drug likeliness of the plant. The outcomes of these findings suggest the therapeutic potential of this plant against pain, diarrhea, inflammation, and tissue toxicity.

Effects of ketamine on nociception and gastrointestinal motility in mice are unaffected by naloxone

1. 1. The present study investigates the effects of ketamine on nociception towards chemical and thermic stimuli and on gastrointestinal transit in mice. 2. 2. The reversibility of these effects by the opioid antagonist naloxone (10 mg/kg) was also assessed. 3. 3. Ketamine promoted dose-related analgesia in both the acetic acid-induced writhing and hot plate tests. 4. 4. Analgesia was not influenced by pretreatment with naloxone. 5. 5. Contrasting the constipation induced by opioids, ketamine enhanced gastrointestinal transit in a dose-dependent manner and this was not modified by naloxone. 6. 6. These results suggest that although ketamine can elicit analgesia, it does not activate opioid mechanisms in subanesthetic doses.

Pharmacological studies of ignavine, an aconitum alkaloid.

Pharmacological properties, especially, analgesic, antipyretio, antiinflammatory, sedative and antidiuretic activities, of ignavine, one of the main alkaloids in Aconite root, are discussed on the basis of the results of blind screening. Ignavine showed antiinflammatory activity in the acetic acid-induced writhing and carrageenin paw edema tests at doses of 50 and 100 mg/kg p.o., which did not produce undesirable effects such as sedation, motor incoordination, muscle relaxation, hypothermia, ulceration or antidiuresis. Pharmacological properties of mesaconitine are also discussed; mesaconitine showed antiinflammatory, antipyretic and weak sedative activities.