Evaluation of analgesic properties of petroleum ether extract of Zingiber officinale

Background: Herbal remedies and alternative therapies have been employed in the treatment of pain from time immemorial. Ginger is a widely used spice with a lot of medicinal properties, and it is especially soothing to the gastro-intestinal system. Most of the analgesics used in modern medicine have side effects to either gastro-intestinal tract or nervous system. Ginger has neither. Scientific evaluation of the analgesic properties of Zingiber officinale is needed. Aim and Objective: The aim of the study was to evaluate the analgesic effect of three doses of orally administered petroleum ether extract of Z. officinale and to compare with morphine. When tested for analgesic activity, to find out the difference in reaction time at various time intervals for each dose of the extract, and their significance. Materials and Methods: Petroleum ether extract of Z. officinale rhizomes was used. Wistar strain albino rats (150-200 g) and Swiss albino mice (20-25 g) housed under standard laboratory conditions were used. The central analgesic activities of the extract were evaluated by the tail clip method and hot plate method. Statistical analysis was done by one-way analysis of variance to compare the means in the experimental groups. Results: In tail clip method, pain was mechanically induced pain and the pain threshold was measured in terms of mice’ reaction time in seconds. All doses of the extract of Z. officinale were capable of increasing the reaction time in mice during the various time periods. Maximum analgesic activity was shown by 800 mg/kg of the extract at 90 minutes. In hot plate test, maximum analgesic activity was shown by 800 mg/kg of the extract at 180 min. At 30 and 60 min, 800 mg/kg of the extract was as effective as the standard drug, morphine. Conclusions: The study revealed that Z. officinale has significant analgesic properties especially in higher doses.

Anti-nociceptive effect of seed extract of Acacia tortilis in rodents

Background: Management of pain is a primary clinical concern for any pathology in medical field. Addiction liability of opioids and troublesome gastrointestinal side effects of NSAIDs leads to intensive research for compound with lesser side effects.The aim of the study to evaluate the anti-nociceptive activity of Acacia Tortilis Seed Extract (ATE) in experimental animals.Methods: First of all, animals were randomly allocated into four groups of six animals each. In acetic acid induced writhing test model, Group I (NC) served as vehicle control received saline/Tween 80 0.1%, 10ml/kg BW orally, group II (ATE-100) and III (ATE-200) received ATE in dose of 100 and 200mg/kg BW orally respectively and group IV received the standard drug diclofenac sodium in dose of 50 mg/kg BW orally. Group I to IV were same in rest of three experimental models. One additional group of standard drugs (group V) morphine sulfate in dose of 5 mg/kg BW subcutaneously (SC) was allocated for screening method hot plate and tail flick tests. In Formalin induced paw licking test, three additional groups (group V) morphine sulfate in dose of 5mg/kg BW SC, group VI- morphine+naloxone (5mg/kg SC +2mg/kg intra-peritoneally (IP) and group VII - ATE+ naloxone (200mg/kg BW orally +2mg/kg BW IP) were also made.Results: The ATE when administered orally in dose of 100 and 200mg/ kg body weight (BW), produced significant analgesic activity (P <0.01) in acetic acid induced writhing syndrome and late phase of formalin test. In the hot plate test in mice and tail flick test in rats, ATE in same doses also showed significant analgesic activity (P <0.05) which is almost equally efficacious to standard drug diclofenac sodium (50mg/kg BW orally) but far less efficacious than morphine sulfate (5mg/kg BW subcutaneous).ATE (200mg/Kg BW orally) activity did not blocked by naloxone (2mg/kg intra-peritoneal).Conclusions: ATE possesss significant anti-nociceptive activity as evidenced in all the animal models of nociception. It might exert its effect through the peripheral mechanism of analgesic action possibly by interference in biosynthesis, release and/or action of prostaglandins and leukotrienes.

A Context-Based Analgesia Model in Rats: Involvement of Prefrontal Cortex / 神经科学通报·英文版

Cognition and pain share common neural substrates and interact reciprocally: chronic pain compromises cognitive performance, whereas cognitive processes modulate pain perception. In the present study, we established a non-drug-dependent rat model of context-based analgesia, where two different contexts (dark and bright) were matched with a high (52°C) or low (48°C) temperature in the hot-plate test during training. Before and after training, we set the temperature to the high level in both contexts. Rats showed longer paw licking latencies in trials with the context originally matched to a low temperature than those to a high temperature, indicating successful establishment of a context-based analgesic effect in rats. This effect was blocked by intraperitoneal injection of naloxone (an opioid receptor antagonist) before the probe. The context-based analgesic effect also disappeared after optogenetic activation or inhibition of the bilateral infralimbic or prelimbic sub-region of the prefrontal cortex. In brief, we established a context-based, non-drug dependent, placebo-like analgesia model in the rat. This model provides a new and useful tool for investigating the cognitive modulation of pain.

Antinociceptive and anti-inflammatory effects of Lantana camara L. extract in mice / Efeitos antinociceptivos do extrato de Lantana camara L. em camundongos

ABSTRACT: he Lantana camara L. belongs to the family Verbenaceae, which contains several active compounds in leaves and roots and which are reported to have medicinal and insecticidal properties. Studies of plants within the same family show the existence of anti-inflammatory activity in paw edema induced by carrageenan, serotonin and histamine and analgesic activity in the acetic acid writhing and tail-flick tests. The present study investigated whether the L. camara extract (ACE) also exerts these effects. The ACE toxicity was studied in male mice, and the percentage of mortality recorded 7 days after treatment was assessed. The ACE was evaluated as an antinociceptive agent in the hot plate, tail-flick and acetic acid writhing tests at a nontoxic dose of 1.0 g/Kg. The results showed that 1.5 g/Kg of ACE was not able to cause death, and doses of 3.0 and 4.0 g/Kg caused 50% and 60% death, respectively, in male mice. In all of the antinociceptive tests, 1 g/Kg of ACE markedly reduced responses to pain. Our findings suggest that ACE may have active anti-inflammatory and antinociceptive properties in much smaller doses than toxic.

RESUMO: Lantana camara L. pertence à família Verbenaceae, a qual contem muitos princípios ativos em suas folhas e raízes com propriedade medicinais e inseticidas. Estudos com plantas da mesma família mostram a existência de propriedades antinflamatórias no modelo de edema de pata induzido pela carragenina, serotonina e histamina, além da atividade analgésica nos testes de contorção induzida pelo ácido acético e da retirada da cauda por estímulo térmico. O presente trabalho investigou os efeitos tóxicos e antinociceptivos do extrato de L. camara (ACE) em camundongos. Para tanto, investigou-se a porcentagem de mortes em 7 dias após a administração de diferentes doses do extrato. Avaliou-se também os efeitos antinociceptivos do ACE pelos testes da placa quente, estimulação térmica da cauda e contorções abdominais induzidas pelo ácido acético com a dose não-tóxica [1,0 g/Kg]. Os resultados mostraram que 1,5 g/Kg do ACE não causou mortalidade, enquanto que 3,0 e 4,0 g/Kg promoveram 50 e 60% de mortalidade, respectivamente. Em todos os testes antinociceptivos, a dose de 1,0 g/Kg do ACE reduziu a resposta à dor. Os presentes resultados indicam que o ACE apresenta propriedades antinflamatórias e analgésicas em doses muito menores que a tóxica.

Evaluation of the anti-nociceptive potential of ethanolic extract of leaves of Bryophyllum pinnatum in experimental animals.

Background: The plant Bryophyllum pinnatum is traditionally used for the treatment of pain and inflammation. The present study was carried out to evaluate the antinociceptive effect of the ethanolic extract of the leaves of B. pinnatum (EEBP) using a hot plate method and acetic acid induced writhing test in mice. Methods: In the hot plate analgesiometer method, the time between the placement on the hot plate and the occurrence of licking of the paws, shaking or jumping off from the plate was recorded as response latency. Total numbers of stretching episodes for 30 mins immediately after acetic acid injection in all the groups were recorded in acetic acid induced writhing method. Pentazocine (10 mg/kg intraperitoneal) and aspirin (500 mg/kg) were used as the standard drugs in the hot plate and acetic acid induced writhing method, respectively. Extract was used in 200, 300 and 400 mg/ kg doses. Results: At all the three doses the EEBP showed signifi cant (p<0.01) anti-nociceptive activity in experimental models of Eddy’s hot plate analgesiometer and acetic acid induced writhing method in mice. Conclusion: The observed pharmacological activities provide the scientifi c basis to support traditional claims, as well as exploring some new and promising leads in the management of pain.

Effect of Gmelina arborea Roxb in experimentally induced infl ammation and nociception.

Background: Gmelina arborea Roxb (Verbenaceae), also known as “Gambhari”, is an important medicinal plant in the Ayurveda. There are no meticulous scientifi c reports on effect of the plant on infl ammation and pain. Objective: To study the anti-infl ammatory and anti-nociceptive properties of aqueous extracts (AE) and methanol extracts (ME) of G. arborea. Materials and Methods: The AE and ME of stembark of G. arborea was prepared by cold maceration and Soxhlet extraction technique respectively. Anti-infl ammatory activity was determined in Wistar albino rats in a model of acute plantar infl ammation induced by carrageenan. The anti-nociceptive activity was evaluated by using hot plate test and writhing test in Swiss albino mice. Signifi cant differences between the experimental groups were assessed by analysis of variance. Results: AE and ME at dose of 500 mg/kg showed maximum inhibition in carrageenan induced infl ammation up to 30.15 and 31.21% respectively. In hot plate test, the AE and ME showed the maximum response of 8.8 ± 0.97 (P < 0.01) and 8.2 ± 1.24 (P < 0.01) respectively at dose of 500 mg/kg when compared with control. AE showed maximum inhibition of writhing response (84.3%) as compared to ME (77.9%) in writhing test at a dose of 500 mg/kg. Conclusion: The fi ndings suggested that G. arborea possess signifi cant anti-infl ammatory and anti-nociceptive activities.

Antinociceptive activity of Sesbania sesban (Linn) wood extracts, a preliminary study.

The wood of the plant Sesbania sesban, is reported to have antinociceptive activity. To validate its folk use in the treatment of pain, wood was extracted successively with petroleum ether, chloroform, ethyl acetate, ethanol, and water to produce respective extracts. The extracts (50 and 100 mg/kg, ip) were screened for antinociceptive activity using hot plate test and acetic acid-induced writhing test in mice. Petroleum ether, chloroform, and ethyl acetate extracts showed significant and dose-dependent activity in both the tests. In order to find out the involvement of opioid receptors, effect of naloxone (1 mg/kg, sc) on the action of extracts was checked in hot plate test. Petroleum ether, chloroform, and ethyl acetate extracts showed significant and dose dependant antinociceptive activity. The antinociceptive action of the extracts was blocked by naloxone, suggesting involvement of opioid receptors in the action.

Neuropharmacological study of Argemone mexicana Linn.

In the present study methanolic and ethyl acetate extracts of Argemone mexicana whole plant (Papaveraceae) were tested orally in swiss albino mice at doses of 100 mg/kg, 200 mg/kg and 400 mg/kg b.w. for CNS related activities. Papaveraceae family is known to have CNS depressant activity, so A. mexicana was evaluated for CNS activities. Significant central and peripheral nociceptive activity was observed for both extracts. Methanolic and ethyl acetate extract have also showed significant decrease in motor activity and fall off time of animals on rotating rod, along with sedative effect by potentiating phenobarbitone-induced sleeping time. In the acute toxicity study, both extracts was found to be safe upto 2500 mg/kg b.w. These results suggested that methanolic and ethyl acetate extracts of Argemone mexicana show analgesic, anxiolytic and sedative effects.

Exercise training attenuates acute hyperalgesia in streptozotocin-induced diabetic female rats

OBJECTIVES: We investigated the effects of chronic (eight weeks) low-to moderate-intensity swimming training on thermal pain sensitivity in streptozotocin-induced diabetic female rats. METHODS: Female Wistar rats (n = 51) were divided into the following groups: trained streptozotocin-induced diabetic rats [hyperglycemic trained (HT)], sedentary streptozotocin-induced diabetic rats [hyperglycemic sedentary (HS)], normoglycemic trained rats (NT) and normoglycemic sedentary rats (NS). Diabetes was induced by a single injection of streptozotocin (50 mg/kg, i.p.). One day after the last exercise protocol (60 min/day, five days/week for eight weeks) in the trained groups or after water stress exposure (ten min/twice a week) in the sedentary groups, the rats were subjected to a hot plate test. RESULTS: After eight weeks of swimming training, streptozotocin-induced diabetic rats presented a significantly lower body mass (trained: 219.5±29 g, sedentary: 217.8±23 g) compared with the normoglycemic groups (trained: 271±24 g, sedentary: 275.7±32 g). Interestingly, we did not find differences in blood glucose levels (mg/dl) between the trained and sedentary groups of the hyperglycemic or normoglycemic rats (HT: 360.2±6.6, HS: 391.7±6.7, NT: 83.8±14.0, NS: 77.5±10.1). In the hot plate test, the rats from the HT group presented a significantly lower latency than the other rats (HT: 11.7±7.38 s, HS: 7.02±7.38 s, NT: 21.21±7.64 s, NS: 22.82±7.82 s). CONCLUSION: Low-to-moderate swimming training for a long duration reduces thermal hyperalgesia during a hot plate test in streptozotocin-induced diabetic female rats.

Analgesic effect of TL-Ⅰ prescription / 中国康复理论与实践

@#ObjectiveTo investigate the analgesic effect of TL-Ⅰ prescription.MethodsHealth ICR mouses were randomly divided into 6 groups: negative control group, positive control group, Tongtian group, large doses group,middle doses group and small doses group. The pain threshold of mouses were detected with hot plate and acetic acid writhing.ResultsTL-Ⅰ prescription can raise the threshold of pain induced by hot plate and reduce the numbers of writhing induced by acetic acid in mice, which was more significant in large doses group. ConclusionTL-Ⅰ prescription can be an effective analgesic.

Influence of intrathecal injection of p-MPPF on the analgesic effects of isoflurane / 中国药理学通报

0. 05) . Compared with Iso analgesic group ( Iso group) ,the TFL or HPPT of co-administration groups ( Iso + M6 group,Iso + M3 group) shortened ( P 0. 05) . Conclusion These findings suggest that the surface analgesic effects of Iso are closely related to the excited 5-HT1A receptor in the spinal cord of mice.

Partial mediation of GABA_A receptor in the antinociceptive stimulation of propofol at spinal level in rats / 中国药理学通报

Aim To observe the effects of propofol at spinal level on nociceptive response in rats and the possible role of GABA_A receptor.Methods In the praxiology test,Sprague-Dawley(SD) female rats were randomized into groups.Bicuculline and propofol were microinjected into intrathecally(ith).The noxious response was evaluated with hot plate and formalin test.In immunohistochemistry test,Fos-like immunoreactivity(FLI) neurons expressed in spinal dorsal horn(DH) induced by formalin intraplantar injection(sc) of one hindpaw were used as a neuroactive marker to observe the effects of propofol on the noxious transmission in DH.Results In hot-plate test,significant analgesia produced by propofol(10 g?L~(-1)) was antagonized about 81%,55%,81% and 97% at 10,20,30 and 40 min by ith bicuculline(0.01 g?L~(-1),P

Electro-acupuncture Analgesia After Neonatal and Adult Capsaicin Treatment / 全日本鍼灸学会雑誌

Effects of capsaicin (CAP) treatment on electro-acupuncture (EA) analgesia were studied by examining, threshold of rats treated CAP in their naonatal and adult periods. Pain threshold of animals were measured as the latency until the occurrence of the hind paw withdrawal in response to heat noxious stimuli by using a hot-plate (HP) method. In control rats, application of EA to the right forepawLI-10, 11), increase the latency to about 160% of the control level (befor the EA application), where as in rats treated with CAP in both neonatal and adult periods, EA application hardly affected the latency.<br>There results suggests that treatment with CAP in both neonatal and adult period abolishes the EA analgesia in rats.

Analgesic Effect of Yunzhi Polysaccharopeptide and Preliminary Analysis of Its Mechanism / 中成药

Objective:To observe the analgesic effect of Yunzhi polysaccharopeptide (PSP) and analyze its mechanism. Methods: The hot plate test in mice and the tail stimulation vocalization test in rats were used.Results: PSP administered po at a dose of 1.0 g/kg for 7 days could produce a significant analgesic effect, which could last for more than two hours. The analgesic effect of PSP disappeared after lesion of mediobasal hypothalamus. Conclusions: PSP could elicit a central analgesic effect.

EXPERIMENTAL STUDY AND CLINICAL OBSERVATION ON ANALGESIC COMPOUND DECOCTION / 重庆医科大学学报

The recipe-analgesic compound decoction composed of herbs according to the theory of Traditional Chinese Medicine and the author's clinical experience of treating painful diseases. The experimental studies showed that the pain threshold of mice in hot-plate test was raised (p

GABA_A receptor partially mediated propofol-induced hyperalgesia at ventrolateral periaqueductal gray(vlPAG) of rats / 中国药理学通报

Aim To observe the effects of propofol on nociceptive response at ventrolateral periaqueductal gray(vlPAG) of rats and the possible role of GABA_A receptor in this prosses.Methods Sprague-Dawley(SD) female rats were randomized into each group.Bicuculline and propofol were microinjected into ventrolateral periaqueductal gray(vlPAG).The noxious response was evaluated by hot plate and formalin test.Fos-like immunoreactivity(FLI) neurons expressed in spinal dorsal horn(DH) induced by formalin intraplantar injection(sc) of one hindpaw were used as a neuroactive marker to observe the effects of propofol on the noxious transmission in DH.Results In hot-plate test,the hyperalgesia induced by propofol(10 g?L~(-1)) vlPAG microinjection was significantly antagonized about(70%),(71%) at 10 and 20 min after (bicu-)culline(25 mg?L~(-1)) vlPAG microinjection(P