Prostaglandins and the mechanism of analgesia produced by aspirin-like drugs. 1973

Size matters: the biochemical logic of ligand type in endocrine crosstalk

The endocrine system is a fundamental type of long-range cell-cell communication that is important for maintaining metabolism, physiology, and other aspects of organismal homeostasis. Endocrine signaling is mediated by diverse blood-borne ligands, also called hormones, including metabolites, lipids, steroids, peptides, and proteins. The size and structure of these hormones are fine-tuned to make them bioactive, responsive, and adaptable to meet the demands of changing environments. Why has nature selected such diverse ligand types to mediate communication in the endocrine system? What is the chemical, signaling, or physiologic logic of these ligands? What fundamental principles from our knowledge of endocrine communication can be applied as we continue as a field to uncover additional new circulating molecules that are claimed to mediate long-range cell and tissue crosstalk? This review provides a framework based on the biochemical logic behind this crosstalk with respect to their chemistry, temporal regulation in physiology, specificity, signaling actions, and evolutionary development.

Leishmania mexicana promotes pain-reducing metabolomic reprogramming in cutaneous lesions

Cutaneous leishmaniasis (CL) is characterized by extensive skin lesions, which are usually painless despite being associated with extensive inflammation. The molecular mechanisms responsible for this analgesia have not been identified. Through untargeted metabolomics, we found enriched anti-nociceptive metabolic pathways in L. mexicana-infected mice. Purines were elevated in infected macrophages and at the lesion site during chronic infection. These purines have anti-inflammatory and analgesic properties by acting through adenosine receptors, inhibiting TRPV1 channels, and promoting IL-10 production. We also found arachidonic acid (AA) metabolism enriched in the ear lesions compared to the non-infected controls. AA is a metabolite of anandamide (AEA) and 2-arachidonoylglycerol (2-AG). These endocannabinoids act on cannabinoid receptors 1 and 2 and TRPV1 channels to exert anti-inflammatory and analgesic effects. Our study provides evidence of metabolic pathways upregulated during L. mexicana infection that may mediate anti-nociceptive effects experienced by CL patients and identifies macrophages as a source of these metabolites.

Pharmacological evaluation of analgesic, anti-inflammatory and antipyretic activities of ethanolic extract of Indigofera argentea Burm. f

ETHNOPHARMACOLOGICAL RELEVANCE

Indigofera argentea Burm. f.; commonly known as neel, jantari, hathio; is traditionally used for the treatment of headache, fever, inflammation and body pain. Local communities also used this plant for the treatment of malaria, jaundice, vertigo and gastric disorders.

AIM OF THE STUDY

This study is aimed to evaluate the toxicity and possible analgesic, anti-inflammatory and antipyretic activities of the ethanolic crude extract of Indigofera argentea (IaCr) to support its use in folk medicine and to screen the phytochemical constituents and antioxidant activity.

MATERIALS AND METHODS

Aqueous ethanolic (30:70) extract of whole plant of Indigofera argentea (IaCr) was prepared and phytochemical study was performed by preliminary methods followed by HPLC and DPPH method. In vivo experiments were performed in Wistar albino rats including hot plate, tail immersion, formalin and capsaicin-induced pain tests in rats and acetic acid-induced writhing test in mice. Anti-inflammatory activity was assessed by using in vitro human red blood cell (HRBC) membrane stabilization and carrageenan-induced rat paw edema test, while antipyretic activity was evaluated by Brewer's yeast-induced pyrexia test.

RESULTS

The crude extract of Indigofera argentea confirmed the presence of flavonoids, glycosides, alkaloids, saponins and tannins as soluble ethanolic constituents in preliminary study. The maximum quantity of gallic acid equivalent (GAE) phenolics, and quercetin equivalent (QE) flavonoid content found was 81 ± 2 mg GAE/g and 56 ± 1.4 mg QE/g of extract respectively. Quantification based on HPLC exposed the presence of phenols and flavonoids, quercetin, gallic acid, caffeic acid, chlorogenic acid, benzoic acid, ferulic acid and coumaric acid. In vivo experiments revealed significant P < 0.05) dose-dependent inhibition in hot plate, tail immersion and capsaicin-induced pain test. IaCr showed significant inhibition of pain latency against both phases in formalin test and considerably decreased the number of writhes caused by acetic acid at the doses of 30, 100 and 300 mg/kg. In the in vitro anti-inflammatory (HRBC) assay, IaCr showed good membrane stability with maximum percentage hemolysis inhibition of 49.29% while in carrageenan-induced paw edema test in rats the IaCr showed significant anti-inflammatory action in a dose-dependent fashion. Statistical significant reduction in rectal temperature was observed at the doses of 100 and 300 mg/kg in yeast-induced pyrexia test in rats.

CONCLUSION

The results of the experimental studies proved the analgesic, anti-inflammatory and antipyretic activities of Indigofera argentea and supported the traditional use of this plant.

Oxaliplatin induces prostaglandin E2 release in vascular endothelial cells

PURPOSE

Oxaliplatin (L-OHP) is known to induce adverse reactions at the injection site, including vascular pain, but the underlying mechanisms have not been clarified. Vascular pain during intravenous L-OHP administration can be inhibited by taking non-steroidal anti-inflammatory drugs (NSAIDs). In this study, we investigated the involvement of the arachidonic acid cascade and prostaglandin (PG) E₂ and 15d-PGJ₂ in vascular pain sensation during intravenous delivery of L-OHP.

METHODS

Cultured normal human umbilical cord vein endothelial cells (HUVECs) were treated with L-OHP or L-OHP + NSAID flurbiprofen for 2 h and analyzed for the release of PGE₂ and 15d-PGJ₂ into culture supernatant by ELISA.

RESULTS

The results showed that L-OHP significantly and dose-dependently increased PGE₂ secretion by HUVECs; however, flurbiprofen effectively prevented PGE₂ increase. On the other hand, cisplatin, another platinum anticancer drug, did not stimulate PGE₂ production. Other PGs, including 15d-PGJ₂, 6-keto PGF_1α, PGF_2α, and PGD₂ were not increased by L-OHP or cisplatin. Protein expression analysis revealed that cyclooxygenase 1 and cytoplasmic PGE synthase involved in constitutive PG metabolism were expressed in HUVECs but not affected by L-OHP exposure.

CONCLUSIONS

This study indicates that L-OHP treatment specifically upregulated PGE₂ secretion by vascular endothelial cells, which may contribute to vascular pain, and that NSAIDs can be used to inhibit PGE₂ release and attenuate L-OHP-induced hyperalgesia.

Quercetin attenuates zymosan-induced arthritis in mice

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by articular lesions, recruitment of inflammatory cells and increased levels of pro-inflammatory cytokine. The intra-articular administration of zymosan is an experimental model that promotes inflammatory parameters resembling RA. Therefore, this model was used to investigate the efficacy of quercetin as a treatment of articular inflammation. Treatment with quercetin dose-dependently reduced zymosan-induced hyperalgesia, articular edema and the recruitment of neutrophils to the knee joint cavity. Histological analysis confirmed that quercetin inhibited zymosan-induced arthritis. The treatment with quercetin also inhibited zymosan-induced depletion of reduced glutathione (GSH) levels, TNFα and IL-1β production, and gp91^phox, prepro-endothelin-1 (preproET-1), and cyclooxygenase-2 mRNA expression. These molecular effects of quercetin were related to the inhibition of the nuclear factor kappa-B and induction of Nuclear factor erythroid 2- related factor (Nrf2)/home oxygenase (HO-1) pathway. Thus, quercetin exerted anti-inflammatory, analgesic and antioxidant effects in experimental arthritis, suggesting quercetin is a possible candidate for arthritis treatment.

Medicinal Uses, Phytochemistry, and Pharmacology of Origanum onites (L.): A Review

Origanum onites L., known as Turkish oregano, has great traditional, medicinal, preservative, and commercial importance. It is used for the treatment of several kinds of ailments, such as gastrointestinal disorders, diabetes, high cholesterol, leukemia, bronchitis, etc. In this review, traditional use, phytochemistry, and pharmacology of O. onites reported between 1988 and 2014 were discussed. This review was prepared based on literature survey on scientific journals and books from libraries and electronic sources, such as Web of Science, PubMed, Scopus, Google Scholar, etc. All databases were searched up to June 2014. Several different classes of terpenoids, triterpene acids, phenolic acids, hydroquinones, flavonoids, hydrocarbons, sterols, pigments, fatty acids, tocopherols, and inorganic compounds were detected mainly in the aerial parts of this plant. Pharmacological studies revealed that extracts obtained from several solvents and individual compounds exhibited antimicrobial, antiviral, antioxidant, insecticidal, anticancer, hepatoprotective, genotoxic, antidiabetic, cholinesterase inhibitory, anti-inflammatory, analgesic activities, etc. O. onites, in general, exhibited remarkable activity potential in almost all test systems. The results of toxicity studies indicated that O. onites did not show any significant toxicity and mutagenicity on Drosophila and Salmonella. Toxicity of the extracts/essential oils and also individual compounds should be evaluated on mammalian cells to ensure their safety. The bioactivity of individual compounds aside from terpenoids should also be assessed in detail. Additionally, mode of action for the bioactive compounds should be evaluated to understand the complex pharmacological effects of these phytochemicals.

The efficacy of acetaminophen-caffeine compared to Ibuprofen in the control of postoperative pain after periodontal surgery: a crossover pilot study

BACKGROUND

Previous studies showed that non-steroidal anti-inflammatory drugs (NSAIDs) have significant benefits in the control of pain after periodontal surgery. Acetaminophen (centrally acting NSAID) is believed to provide less analgesic efficacy than ibuprofen (centrally and peripherally acting NSAID). This study compared an alternative combination of acetaminophen, 500 mg, with caffeine, 30 mg, to ibuprofen, 400 mg, in pain management after periodontal surgeries.

METHODS

A prospective, randomized, double-masked crossover clinical trial was conducted on 15 patients. Open flap debridement was performed on two quadrants with a 3-week interval in between. Each quadrant was randomly assigned to acetaminophen, 500 mg, with caffeine, 30 mg, or ibuprofen, 400 mg, immediately after surgery and 8 hours after the first dose. Postoperative pain was assessed during the first 8 hours and on the following day using the 101-point numeric rate scale (NRS-101) and the four-point verbal rating scale (VRS-4).

RESULTS

Using the NRS-101, the acetaminophen-caffeine group showed statistically significantly lower mean pain scores than the ibuprofen group at 1 and 2 hours (P = 0.002), whereas at 6, 7, and 8 hours, the ibuprofen group showed statistically significantly lower mean pain scores (P <0.001). Using the VRS-4, there was no statistically significant difference between the two groups at all periods (P >0.05).

CONCLUSION

Acetaminophen, 500 mg, with caffeine, 30 mg, can be used efficiently in controlling postoperative pain after open flap debridement, especially in patients with gastric ulcers or bleeding tendency because acetaminophen is less hazardous than ibuprofen.

Synthesis, analgesic and anti-inflammatory evaluation of some new 3H-quinazolin-4-one derivatives

In this study, we have synthesized a series of 3H-quinazolin-4-ones in order to obtain new compounds with potential analgesic and anti-inflammatory activity. The structures of the newly synthesized compounds were confirmed by means of infrared, nuclear magnetic resonance and mass spectroscopy. Some compounds were evaluated for their analgesic and anti-inflammatory activities by writhing and carrageenan-induced rat paw edema tests, respectively. In comparison to the standard drug indomethacine, compounds 4, 6c, 12-14, 16, 18, 19, and 22 induced significant reduction in the writhing response while compounds 6c, 12, 14, 16, 18, and 22 produced a good dose-dependent anti-inflammatory activity. The best dual analgesic / anti-inflammatory relative activity was observed with compounds 6c, 14, 16, 18, and 22.

John R. Vane, « pharmacologue de l’endothélium vasculaire », 1927–2004

The work of John Vane greatly contributed to the use of aspirin in cardiology. The impact of aspirin administration at low dose for the prevention of stroke or coronary attack results from its effect on enzymes regulating the production of prostaglandins. After understanding the mechanism of interaction between aspirin and the vascular endothelium, Vane proposed assigning a major physiological function to the vascular endothelium which then became a pharmacological target for new drugs. Using an ingenious "real time" biological assay of bloodstream hormones irrigating an isolated organ called the "blood-bathed organ cascade", John Vane developed a system for highly sensitive monitoring of several mediators like angiotensin, bradykinin and prostaglandins and discovered prostacyclin, a potent platelet aggregation inhibitor. Vane explained anti-inflammatory drugs effects (among which aspirin remains the leader) through their activity on cyclo-oxygenase and inhibition of prostacyclin and thromboxane production. Another cyclooxygenase isoform, so-called type 2, has been discovered in 1991. Thus, besides the constitutive COX-1, participating to stomach protection and renal artery vasodilatation, a COX-2 enzyme is existing, induced by inflammatory phenomenons and cytokines stimulation, allowing to design specific inhibitors "coxibs", playing an increasing but controversial role in the struggle against inflammation. He won Albert Lasker Prize in 1977 and Nobel Prize in medicine and physiology (shared with Sune Bergström and Bengt I. Samuelson) in 1982.

Molecular determinants of P2Y2 nucleotide receptor function: implications for proliferative and inflammatory pathways in astrocytes

In the mammalian nervous system, P2 nucleotide receptors mediate neurotransmission, release of proinflammatory cytokines, and reactive astrogliosis. Extracellular nucleotides activate multiple P2 receptors in neurons and glial cells, including G protein-coupled P2Y receptors and P2X receptors, which are ligand-gated ion channels. In glial cells, the P2Y2 receptor subtype, distinguished by its ability to be equipotently activated by ATP and UTP, is coupled to pro-inflammatory signaling pathways. In situ hybridization studies with rodent brain slices indicate that P2Y2 receptors are expressed primarily in the hippocampus and cerebellum. Astrocytes express several P2 receptor subtypes, including P2Y2 receptors whose activation stimulates cell proliferation and migration. P2Y2 receptors, via an RGD (Arg-Gly-Asp) motif in their first extracellular loop, bind to alphavbeta3/beta5 integrins, whereupon P2Y2 receptor activation stimulates integrin signaling pathways that regulate cytoskeletal reorganization and cell motility. The C-terminus of the P2Y2 receptor contains two Src-homology-3 (SH3)-binding domains that upon receptor activation, promote association with Src and transactivation of growth factor receptors. Together, our results indicate that P2Y2 receptors complex with both integrins and growth factor receptors to activate multiple signaling pathways. Thus, P2Y2 receptors present novel targets to control reactive astrogliosis in neurodegenerative diseases.

Efficacy of Ibuprofen-Hydrocodone for the Treatment of Postoperative Pain After Periodontal Surgery

BACKGROUND

Previous studies have shown that non-steroidal anti-inflammatory drugs (NSAIDs) have significant benefits in the control of postoperative pain after periodontal or oral surgical procedures. The combination of a peripherally acting NSAID with a centrally acting opioid drug is found to be more effective. The purpose of this study was to compare an alternative combination of ibuprofen 400 mg with 5 mg of hydroxycodone to ibuprofen 400 mg used alone in the management of pain following periodontal surgery.

METHODS

This study used a double-masked cross-over design with the patients acting as their own controls. Twelve patients underwent two periodontal surgeries in different quadrants of the same dental arch at least 2 weeks apart. A standardized amount of local anesthetic and similar extent and duration of surgery for each side was required. The patients received four doses of medication at predetermined intervals and filled out a visual analog pain scale every 2 hours for the first 12 hours after surgery.

RESULTS

The overall pain reported by the patients on visual analog scale was 1.55 (SE +/- 0.16), out of a possible 10. More pain was reported with ibuprofen alone, 1.81 (SE +/- 0.12), compared to the ibuprofen with hydrocodone combination, 1.30 (SE +/- 0.16). The difference was statistically significant (P<0.05).

CONCLUSION

The findings suggest that a combination analgesic preparation of ibuprofen (400 mg) with hydrocodone (5 mg) results in better pain control compared to ibuprofen used alone.