Allergic sensitization increases contractile responses to 5-HT in guinea pig aorta.

Epidemiological and clinical studies suggest that asthma is associated with adverse cardiovascular outcomes, but its mechanism is uncertain. 5-Hydroxytryptamine (5-HT) is a mediator involved in asthma and in cardiovascular functioning. Thus, in the present study, we explored whether allergic sensitization in guinea pigs modifies 5-HT-induced contractile responses and 5-HT2A receptor expression in thoracic aorta rings. We found that sensitization produced a significant increase of 100 microM 5-HT-induced contractions of aorta rings (~27 % greater contraction than in non-sensitized animals, p<0.05). Preincubation with 10 nM ketanserin (a 5-HT2A receptor antagonist) reduced by ~30 % (p=0.003) and ~36 % (p=0.005) the area under the curve of 5-HT-induced contractions in aortas from non-sensitized and sensitized animals, respectively. There were no differences between sensitized and non-sensitized animals with respect to mRNA (qPCR) and protein (Western blot) expression of 5-HT2A receptor in thoracic aortas. We concluded that in this guinea pig model of asthma, allergic sensitization is not confined to airways, but also affects arterial contractile responses to 5-HT; changes in the expression of the 5-HT2A receptor appear not to be involved in this phenomenon.

Pain and knee damage in male and female mice in the medial meniscal transection-induced osteoarthritis.

OBJECTIVE: To investigate sex effects on pain-related behaviors in the medial meniscal transection (MMT) knee osteoarthritis (OA) model. METHODS: Experiments were performed in male and female C57BL/6J mice (12/group/sex). MMT was induced by transection of the medial collateral ligament and the medial meniscus. Sham-operated and naïve mice served as controls. Mechanical and heat sensitivity in hind paws, hind limb use, and locomotor activity were measured for 3 months. Knee histology was performed on week 12. RESULTS: In males, MMT triggered a bi-phasic mechanical hypersensitivity and decreased load on OA limb, with an acute post-operative (1-5 days) and chronic (3-12 weeks) OA phases separated by a remission in the intermediate phase (1-2 weeks). Females showed a less pronounced bi-phasic pattern, with a greater mechanical hypersensitivity, but not poorer limb use, than males in the intermediate phase (maximal difference: 1.1 g, 95% confidence intervals (CI) [0.7, 1.5]). There were no major sex differences in the chronic phase. MMT did not induce heat hypersensitivity or change in locomotor activity in the chronic phase in both sexes. MMT caused more severe cartilage damage in males than in females (maximal difference: 1.1 score points, 95% CI [1.9, 0.3]), and a comparable between sexes osteophyte formation. The knee damage did not correlate with pain. CONCLUSIONS: MMT modelled human knee OA well, capturing cartilage destruction and osteophyte formation, mechanical pain, and poorer limb use in both sexes. Sex differences in pain were modality- and time-dependent, reflecting complex sex-related features of human OA.

Influence of behavioral traits in the inter-individual variability of nociceptive, emotional and cognitive manifestations of neuropathic pain.

Neuropathic pain is a complex disorder associated with emotional and cognitive deficits that may impair nociceptive manifestations. There is high inter-individual variability in the manifestations of human neuropathic pain, which largely depends on personality traits. We aim to identify the influence of different behavioral traits in the inter-individual vulnerability to neuropathic pain manifestations using behavioral, electrophysiological and genetic approaches. We first selected mice with extreme social and emotional traits and look for correlation with the spontaneous neuronal activity in the central amygdala. Neuropathic pain was induced to these mice to evaluate the influence of behavioral traits on nociceptive manifestations and gene expression profiles in the amygdala. Our results show an association of the spontaneous central amygdala neuronal activity with the sociability behavior. We demonstrate that low sociable, high anxious and low depressive phenotypes develop enhanced nociceptive hypersensitivity after nerve injury. However, greater emotional alterations and cognitive impairment are observed in high sociable, anxious-like and depressive-like mice, indicating that nociceptive, emotional and cognitive manifestations of neuropathic pain do not correlate with each other. Gene analyses identify high Pdyn and Il6 levels in the amygdala as indicative of enhanced nociceptive hypersensitivity and reveal an association between high Gadd45 expression and attenuated emotional and cognitive manifestations of neuropathic pain.

Effects of pregabalin on the nociceptive, emotional and cognitive manifestations of neuropathic pain in mice.

BACKGROUND: Preclinical drug discovery for the treatment of chronic pain is at present challenged by the difficulty to study behaviours comparable to the complex human pain experience in animals. Several reports have demonstrated a frequent association of chronic pain in humans with affective disorders, such as anxiety and depression, and impaired cognitive functions, including memory and decision making, and motivation for goal-directed behaviours. In this study, we validated different behavioural outcomes to measure the emotional and cognitive manifestations of neuropathic pain induced in mice by partial sciatic nerve ligation. METHODS: In these mice, we evaluated at different time points the nociceptive responses, the anxiety- and depressive-like behaviours, the anhedonic state, object recognition memory and the operant responding maintained by food and the effects of the repeated administration of pregabalin on these manifestations. RESULTS: Our results demonstrated that the presence of allodynia and hyperalgesia in neuropathic pain mice was associated with increased anxiety- and depressive-like behaviours, reduced memory functions, development of an anhedonic state and impaired motivation to obtain food in the operant task. Chronic pregabalin treatment improved the nociceptive, anxiety-like and anhedonic responses, as well as the memory deficit, but did not modify the depressive-like alterations and the decreased motivation in these mice. CONCLUSIONS: These results indicate that some emotional manifestations of chronic pain do not necessarily resolve when pain is relieved and underline the relevance to evaluate multiple behavioural responses associated with chronic pain, including the affective-motivational and cognitive behaviours, to increase the predictive value of preclinical drug discovery. WHAT DOES THIS STUDY ADD?: In this study, we have validated different behavioural outcomes allowing a reliable measurement of the emotional and cognitive manifestations of neuropathic pain induced in mice by partial sciatic nerve ligation. These results underline the relevance to evaluate these multiple pain-related alterations to improve the predictive value of preclinical drug discovery.

Analgesic, anti-inflammatory and antioxidant properties of Buddleja globosa, Buddlejaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: Buddleja globosa, known as "matico", is employed in Chile for wound healing. AIM OF THE STUDY: To validate the traditional use of the crude drug through in vivo and in vitro evaluation of the anti-inflammatory, analgesic and antioxidant properties of its extracts. MATERIALS AND METHODS: Sequential hexane, dichloromethane, methanol and total methanol extracts were studied using bioguided fractionation. The following activities were investigated: analgesic (writhing test), oral and topic anti-inflammatory (paw- and ear-induced edema), free radical scavenging and antioxidant activities (1,1-diphenyl-2-picrylhydrazyl, DPPH, superoxide anion, lipid peroxidation and xanthine oxidase inhibition). Sodium naproxen, nimesulide, indomethacin were used as reference drugs for in vivo, quercetin and allopurinol for in vitro assays. RESULTS: A mixture of alpha- and beta-amyrins was isolated from the hexane extract that showed 41.2% of analgesic effect at 600 mg/kg, inhibited by 47.7 and 79.0% the arachidonic acid (AA) and 12-deoxyphorbol-13-decanoate (TPA)-induced inflammation at 3mg/20 microL/ear, respectively. A mixture of beta-sitosterol, stigmasterol, stigmastenol, stigmastanol and campesterol was isolated from the fraction CD4-N and beta-sitosterol-glycoside from the fraction CD5-N, reducing TPA-induced inflammation by 78.2 and 83.7% at 1mg/20 microL/ear, respectively. The fraction CD4-N at 300 mg/kg also showed analgesic activity (38.7%). The methanol extract at 600mg/kg per os showed anti-inflammatory effect (61.4%), topic anti-inflammatory (56.7% on TPA) and analgesic activity (38.5%). Verbascoside and luteolin-7-O-glucoside were the major components of the methanol extract; apigenin 7-O-glucoside was also detected. Inhibition of superoxide anion, lipoperoxidation, and DPPH bleaching effect was found in the methanol serial and global extracts. CONCLUSIONS: The present report demonstrate the analgesic and anti-inflammatory properties of Buddleja globosa and validate its use in Chilean traditional medicine.

Analgesic activity of Ugni molinae (murtilla) in mice models of acute pain.

Leaf extracts of Ugni molinae Turcz. (Myrtaceae) are used in Chilean folk medicine as analgesic and anti-inflammatory. The antinociceptive effect of dichloromethane (DCM), ethyl acetate (EA) and methanol (ME) leaf extracts was assessed by intraperitoneal, oral and topical administration in writhing, tail flick, and tail formalin tests in mice. The extracts showed a dose-dependent antinociceptive activity in all the assays under different administration routes. The ED(50) values for the different tests for the DCM, EA, ME extract and reference drug (ibuprofen) were as follows. Writhing test in acetic acid (i.p. administration): 0.21, 0.37, 1.37 and 0.85mg/kg, respectively; tail flick test (oral administration): 199, 189, 120 and 45.9mg/kg. The EC(50) values for tail flick test were (topical administration): 2.0, 0.35, 1.4 and 8.2% (w/v), respectively; and the topical analgesic effects were (formalin assay) 75.5, 77.5, 31.6 and 76.5%, respectively. Ugni molinae extracts produce antinociception in chemical and thermal pain models through a mechanism partially linked to either lipooxygenase and/or cyclooxygenase via the arachidonic acid cascade and/or opioid receptors. Flavonoid glycosides and triterpenoids have been isolated from the plant and can be associated with the observed effect. Our results corroborate the analgesic effects of Ugni molinae, and justify its traditional use for treating pain.

Actividades biológicas de Xenophyllum poposum Phil. (Asteraceae), planta del altiplano chileno / No disponible

No disponible

Analgesic-antiinflammatory properties of Proustia pyrifolia.

The antiinflammatory (per os and topic) and analgesic (per os) properties of the aerial part of Proustia pyrifolia a species in danger of extinction were investigated, and the major compounds of two of its active extracts were isolated. In addition, the evaluation of cytotoxicity in three tumoral cell lines and the acute toxicity of the crude methanol extract were also assayed, together with the antioxidant activity for the different extracts of this species. The results of the evaluation of the topic antiinflammatory activities induced by arachidonic acid, and phorbol 12-myristate 13-acetate of the different extracts showed that this species possesses active constituents that could diminish cyclo-oxygenase and lipoxygenases activities, the enzymes that allow the synthesis of proinflammatory endogenous substances as prostaglandin E(2) and leukotrienes, respectively. Our results corroborate the antiinflammatory and analgesic effects of Proustia pyrifolia, and could justify its use in folk medicine for the treatment of rheumatic and gout illnesses. From bio-active extracts beta-sitosterol, quercetin and dihydroquercetin were obtained, and these compounds could explain in part the antiinflammatory, analgesic and antioxidant activities of this species. The crude methanol extract did not present acute toxicity or cytotoxic activity, however only this extract exhibited antioxidant activity.

Bioactive phenolic derivatives from Acaena splendens methanol extract.

Acaena splendens H. et A. has been used in Chilean folk medicine for the treatment of fever and inflammation. A description of the in vivo reduction of bacterial pyrogen-induced fever in rabbits and carrageenan-induced paw oedema in guinea pigs is presented. The methanol extract named ME-1, obtained after succesive extractions with petroleum ether and dichloromethane, showed a strong antipyretic action (45.7% of effect), though the antiinflammatory activity was only observed after submitting this extract to column fractionation, giving a crude mixture of flavonoids named C4 with both activities (55.7% and 98.9% of antiinflammatory and antipyretic effect respectively at a dose of 600 mg/kg). The bioassay-guided fractionation by column chromatography afforded the active fraction, which contained (-,-)-epicatechin, tiliroside, 7-O-acetyl-3-O-beta-D-glucosyl-kaempferol and 7-beta-D-glucosyloxy-5-hydroxy-chromone.

Active constituents isolated from Psoralea glandulosa L. with antiinflammatory and antipyretic activities.

The antiinflammatory and antipyretic activities of the petroleum ether extract (PEE), dichloromethane extract (DME) and methanol extract (ME1) of the aerial part of Psoralea glandulosa L. (Papilionaceae) were studied. The bioactivity-guided fractionation of the active extracts yielded the isolation of bakuchiol (Bk) from the petroleum ether as the active compound, cyclobakuchiols A and B (Cbk), and angelicin (Ang) from DME.

A new cucurbitacin glycoside from Kageneckia oblonga (Rosaceae).

A novel cucurbitacin glycoside has been isolated from aerial parts of Kageneckia oblonga R. et P. and shown to be 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycuc urbita-5,24-dien-11-one. The structure was established by usual spectroscopic and two-dimensional (2D) NMR techniques. This compound has found to be nontoxic when tested in-vivo cell culture assays. In previous investigations we reported 23,24-dihydrocucurbitacin F and prunasine. This was the first report on cucurbitacins from the genus Kageneckia (Rosaceae).

Effect of bakuchiol on leukocyte functions and some inflammatory responses in mice.

The effects of bakuchiol, a meroterpenoid isolated from the leaves of Psoralea glandulosa L., on phospholipase A2 (PLA2) activity from different sources, human neutrophil responses, zymosan air pouch and topical inflammation in mice, were investigated. This natural product was a weak inhibitor of secretory and intracellular PLA2 but dose-dependently reduced the formation of LTB4 and TXB2 by human neutrophils and platelet microsomes, respectively. In addition, bakuchiol inhibited degranulation in human neutrophils, whereas superoxide generation was not affected. In mice, bakuchiol decreased cell migration, myeloperoxidase activity and eicosanoid levels in the air pouch inflammation induced by zymosan. After topical administration, this compound was effective as an inhibitor of oedema and myeloperoxidase activity in the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear oedema and significantly reduced the PGE2 content and ear oedema in the arachidonic acid-induced response. Bakuchiol is a natural anti-inflammatory agent able to control leukocytic functions such as eicosanoid production, migration and degranulation in the inflammatory site.

Two new antiinflammatory elemanolides from Centaurea chilensis.

Two previously undescribed elemanolide esters, the 2-methylpropanoate and 2-methyl-2-propenoate of 11,13-dehydromelitensin, were isolated in the course of a bioassay-guided fractionation from the aerial parts of Centaurea chilensis Hook. et Arn., used traditionally to treat 'gout and rheumatism'. The mixture of both substances exhibits anti-inflammatory activity in the carrageenan-induced paw edema assay.