Synthesis, characterization, molecular modeling studies, and biological evaluation of metal piroxicam complexes (M = Ni(II), Pt(IV), Pd(II), Ag(I)) as antibacterial and anticancer agents.

Four piroxicam metal complexes; NiL2 , PtL2 , PdL2 , and AgL were synthesized and characterized by different techniques with enhanced antibacterial and anticancer activity. Regarding in vitro antimicrobial activity, complex NiL2 displayed potent antibacterial effect against Escherichia coli and Pseudomonas aeruginosa that was 1.9-folds higher than piroxicam (minimum inhibitory concentration [MIC] = 31.85, 65.32 µM), respectively. In case of G+ve bacteria, complex PtL2 had potent activity on Staphylococcus aureus which was 2.1-folds higher than piroxicam (MIC = 43.12 µM), while activity of complex AgL against Enterococcus faecalis was threefolds higher than piroxicam (MIC = 74.57 µM. Complexes PtL2 and PdL2 exhibited higher inhibition of DNA gyrase than piroxicam (IC50 = 6.21 µM) in the range of 1.9-1.7-folds. The in vitro antiproliferative activity depicted that all investigated complexes showed better cytotoxic effect than piroxicam, specifically Pt and Pd complexes which had lower IC50 values than piroxicam on human liver cancer cell line HepG2 by 1.8 and 1.7-folds, respectively. While Pd and Ag complexes showed 2 and 1.6-folds better effect on human colon cancer cell line HT-29 compared with piroxicam. Molecular modeling studies including docking on Stranded DNA Duplex (1juu) and DNA gyrase enzyme (1kzn) that gave good insight about interaction of complexes with target molecules, calculation of electrostatic potential map and global reactivity descriptors were performed.

Phytochemical analysis and gastroprotective effect of Stellaria media (L.) Vill. methanolic extract on piroxicam-induced gastric ulcer in Wistar rats.

Stellaria media L. has traditionally been used to treat inflammatory and gastrointestinal ailments. This study aimed to phytochemically characterize the S. media extract and explore its anti-ulcer efficacy against piroxicam-induced stomach lesions in Wistar rats. Phytochemical analysis was performed and antioxidant capacity of extract was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. In vivo, piroxicam (30mg/kg) was administered to induce gastric ulceration. Gastro protective effect of S. media extract was observed at 150, 300 and 450mg/kg, respectively. While omeprazole (20mg/kg) was used as a conventional anti-ulcer drug. After oral treatment for 14 days, stomach acidic secretions, ulcerogenic indices, hematological markers and oxidative stress parameters were assessed along with histological examination. The existence of polyphenol contents in S. media extract was confirmed in correlation to a marked DPPH inhibition (IC50 27.94µg/mL). S. media extract resulted in a dose-dependent elevation in gastric pH while a decrease in acid volume, acidity and ulceration. Also, S. media extract administration restored the impaired hematological markers (RBCs, Hb, WBCs and PLTs) and decreased oxidative stress by reducing oxidants (TOS and MDA) while raising antioxidants (TAC and CAT). Furthermore, gastric histological results corroborated the aforementioned findings. Conclusively, S. media could provide a promising protective effect against drug-induced gastric ulceration.

Comparative study of piroxicam and nitroglycerin on prostaglandin-modulated blood and electrolyte indices during di-estrous in female Wistar Rats.

OBJECTIVE: Endogenous prostaglandins are involved in hemostasis, renal excretion of electrolytes, and implicated in dysmenorrhea. Piroxicam and Nitroglycerin are common drugs used in treating dysmenorrhea by inhibiting the cyclooxygenase pathway involved in prostaglandin production. However, studies comparing the effects of these drugs on prostaglandin-modulated hemostasis and renal function are lacking. METHODS: Fifteen female rats (120-160g) were divided into 3 groups (20 per group), namely Control (distilled water, 0.3 mL), Piroxicam treated (3mg/kg) and Nitroglycerin treated (1 mg/kg). Di-estrous phase was confirmed in animals in each group using the Pipette smear method. Treatment was administered for 4 days covering the estrous cycle. Bleeding and clotting time were assessed and blood concentrations of sodium, potassium, urea and platelet counts were evaluated in all phases. Data were analyzed using one-way ANOVA and Newman-Keuls post-hoc test. Statistical significance was considered at p<0.0. RESULTS: The nitroglycerin-treated group showed significant increases in blood potassium during di-estrous while the piroxicam-treated group showed significant increases in blood potassium, urea and clotting time with a significant decrease in sodium levels during di-estrous compared to controls. Results obtained in other phases were not significant compared to controls. CONCLUSIONS: The study showed that Nitroglycerin produces minimum alteration of blood and electrolyte indices compared to piroxicam during di-estrous.

Distension evoked mucosal secretion in human and porcine colon in vitro.

It was suggested that intestinal mucosal secretion is enhanced during muscle relaxation and contraction. Mechanisms of mechanically induced secretion have been studied in rodent species. We used voltage clamp Ussing technique to investigate, in human and porcine colonic tissue, secretion evoked by serosal (Pser) or mucosal (Pmuc) pressure application (2-60 mmHg) to induce distension into the mucosal or serosal compartment, respectively. In both species, Pser or Pmuc caused secretion due to Cl- and, in human colon, also HCO3- fluxes. In the human colon, responses were larger in proximal than distal regions. In porcine colon, Pmuc evoked larger responses than Pser whereas the opposite was the case in human colon. In both species, piroxicam revealed a strong prostaglandin (PG) dependent component. Pser and Pmuc induced secretion was tetrodotoxin (TTX) sensitive in porcine colon. In human colon, a TTX sensitive component was only revealed after piroxicam. However, synaptic blockade by ω-conotoxin GVIA reduced the response to mechanical stimuli. Secretion was induced by tensile rather than compressive forces as preventing distension by a filter inhibited the secretion. In conclusion, in both species, distension induced secretion was predominantly mediated by PGs and a rather small nerve dependent response involving mechanosensitive somata and synapses.

Comparison of Preoperative Analgesics on the Efficacy of Inferior Alveolar Nerve Block with Patients Having Symptomatic Irreversible Pulpitis: A Double-Blinded, Randomized Controlled Trial.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of preoperative analgesics on inferior alveolar nerve blocks (IANB) during root canal treatment in patients with symptomatic irreversible pulpitis of the mandibular molars. METHODS: This study was a randomized, double-blinded, superiority trial with a parallel study design. A total of 120 subjects with symptomatic irreversible pulpitis were randomly assigned to one of four groups: group A (con- trol, Vitamin E, Evion 400 mg), group B (Diclofenac sodium, Voltral SR100 100 mg), group C (Piroxicam, Feldene 20 mg), and group D (Tramadol, Tramal 50 mg). The patients recorded preoperative pain levels, and after admin- istration of local anaesthesia intraoperative pain levels using the Heft-Parker visual analogue scale before and after the oral administration of the analgesics. Statistical analysis was performed using the Kruskal-Wallis test. RESULTS: All the analgesic groups showed a significant effect on the efficacy of the inferior alveolar nerve block in contrast to the control group (p<0.05). However, no significant difference was found between the drug groups on the effectiveness of the inferior alveolar nerve block (p>0.05). No side effects were reported in the present study. CONCLUSION: Preoperative analgesics significantly increase the effectiveness of inferior alveolar nerve block in patients with symptomatic irreversible pulpitis. Therefore, preoperative analgesics should be considered to increase the effectiveness of inferior alveolar nerve block in patients with symptomatic irreversible pulpitis on the mandibular molars. (EEJ-2023-02-033).

Protective potential of piroxicam on human peripheral blood mononuclear cells against the suppressive capacity of glioblastoma cell lines.

Dexamethasone, a common medication used in the treatment regimen of glioblastoma, has broad inhibitory effects on the immune responses. Here, in an in vitro study, we examined the effects of piroxicam, a potent substitute for dexamethasone, on peripheral blood mononuclear cells (PBMCs) co-cultured with two glioblastoma cell lines, U-87 MG and A-172 cells. MTT assay was used to determine the proliferation of PBMCs treated with piroxicam, or dexamethasone. In addition, to evaluate the effects of drugs on the cell cycle distribution, DNA content per cell was analyzed in PBMCs and A-172 cell lines using flow cytometry. Oxidative parameters, including superoxide dismutase-3 (SOD3) activity and total anti-antioxidant capacity, lactate dehydrogenase (LDH) activity, as well as IFN-γ and TGF-ß levels were measured in PBMCs alone or in the presence of cell lines using ELISA. Unlike dexamethasone, piroxicam showed a protective effect on PBMCs against both glioblastoma cell lines. Furthermore, while dexamethasone reduced the proliferation of PBMCs, piroxicam had no adverse effect on the proliferation. Cell cycle analysis showed a reduction in the G2/M phase in piroxicam-treated A-172 cells. Additionally, dexamethasone limited the cell cycle progression by increasing the fraction of PBMCs in G0/G1. Interestingly, after co-culturing piroxicam-treated PBMCs with cell lines, a remarkable rise in the LDH activity was observed. Although not significant, piroxicam partially decreased TGF-ß levels in both cell lines. Our findings suggested a protective effect of piroxicam, but not dexamethasone, on PBMCs against inhibitory mechanisms of two glioblastoma cell lines, U-87 and A-172 cells.

Effectiveness of new selenium-enriched mutated probiotics in reducing inflammatory effects of piroxicam medication in liver and kidney.

Piroxicam is used to treat the pain, swelling, and stiffness associated with osteoarthritis and rheumatoid arthritis, but it has many side effects, such as hypertension, elevation of liver enzymes, and hepatitis. This study used selenium-enriched probiotics to reduce the side effects of piroxicam on the liver and kidney tissues and functions. Forty-eight male albino mice were randomly assigned to control, piroxicam (P), piroxicam plus selenium-enriched Lactobacillus plantarum PSe40/60/1 (P + SP), piroxicam plus selenium-enriched Bifidobacterium longum BSe50/20/1 (P + SB), selenium-enriched L. plantarum PSe40/60/1 (SP), and selenium-enriched B. longum BSe50/20/1 (SB) groups. In this study, the function of the liver and kidney was biochemically determined; the histopathology of the liver and kidney tissues was microscopically examined and the expression of inflammatory and anti-inflammatory genes in liver and kidney tissues was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Liver and kidney functions were significantly reduced in the piroxicam group compared with control. Liver and kidney tissues were damaged in the piroxicam group while they appeared more or less normal in the SB group. The expression of inflammatory genes was significantly up-regulated in the liver and kidney tissues of the piroxicam group compared to the control group. The expression of anti-inflammatory genes was significantly down-regulated in the liver and kidney of the piroxicam group and up-regulated in the liver and kidney of the SB group compared to the control group. Therefore, these mutated strains of probiotics were useful in reducing the side effects of the piroxicam drug on the liver and kidney.

[Possibilities of individual choice of NSAIDs on the example of the oxicam class, taking into account clinical and pharmacological characteristics]. / Vozmozhnosti individual'nogo podkhoda k vyboru nesteroidnogo protivovospalitel'nogo preparata dlya komorbidnogo patsienta s uchetom kliniko-farmakologicheskikh kharakteristik preparata na primere klassa oksikamov.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are traditionally used to relieve pain syndromes. The class of NSAIDs includes oxicams (meloxicam, tenoxicam, lornoxicam) - drugs with pronounced analgesic and anti-inflammatory effects. Oxicams have common properties of the class, but at the same time, due to structural differences from all other NSAIDs, they differ in a number of clinical and pharmacological characteristics, knowledge of which will help to individualize the choice of the drug.

Ketoprofen, piroxicam and indomethacin-suppressed quorum sensing and virulence factors in Acinetobacter baumannii.

AIM: Quorum sensing (QS) inhibition is a promising strategy to suppress bacterial virulence and control infection caused by Gram-negative and Gram-positive bacteria. This study explores the QS inhibiting activity of the non-steroidal anti-inflammatory drugs (NSAIDs) in Acinetobacter baumannii. METHODS AND RESULTS: Ketoprofen, piroxicam and indomethacin revealed QS inhibition via elimination of violacein production of the reporter strain Chromobacterium violaceum ATCC 12472 without affecting bacterial growth. The minimal inhibitory concentration (MIC) of ketoprofen, piroxicam and indomethacin was determined against A. baumannii strains ATCC 17978, ATCC 19606, A1, A11 and A27 by the microbroth dilution method. The MICs of ketoprofen against tested isolates were 0.7-6.25 mg ml-1 , piroxicam MICs were 1.25-2.5 mg ml-1 , and indomethacin MICs were 3.12-12.5 mg ml-1 . Those compounds significantly inhibited QS-associated virulence factors such as biofilm formation, and surface motility, as well as, significantly increased bacterial tolerance to oxidative stress without affecting bacterial growth. On the molecular level, the three compounds significantly inhibited the transcription of QS regulatory genes abaI/abaR and biofilm-regulated genes cusD and pgaB. Molecular docking analysis revealed the potent binding affinity of the three compounds with AbaI via hydrogen and/or hydrophobic bonds. CONCLUSION: These results indicate that NSAIDs, ketoprofen, piroxicam and indomethacin, could be potential inhibitors of the QS and could suppress the QS-related virulence factors of A. baumannii. SIGNIFICANCE AND IMPACT: Ketoprofen, piroxicam and indomethacin could provide promising implications and strategies for combating the virulence and pathogenesis of A. baumannii.

Box-Behnken design optimization and in vitro cell based evaluation of piroxicam loaded core-shell type hybrid nanocarriers for prostate cancer.

In the present research, piroxicam entrapped core-shell lipid-polymer hybrid nanocarriers were developed and also evaluated in terms of nanoparticle features and cell-based in vitro efficacy on prostate cancer cells. Box-Behnken optimization approach was implemented to evaluate the impact of the input variables, namely phospholipid/PLGA ratio, total lipids/lecithin molar ratio, and piroxicam concentration, on two output variables: particle size and entrapment efficiency. Surface charge, size distribution, morphological structure of particles, drug release profiles, presence of outer lipid shell, thermal profile and possible interactions and storage stability of core-shell nanocarriers of piroxicam were studied as particle features. Cell viability, apoptosis and cell cycle arrest studies were utilized for in vitro cell-based evaluation of the core-shell nanosystems. The hybrid nanocarrier formulation with a particle size of 119.2 nm and an entrapment efficiency of 91.7% at the center point of the design was selected as the optimized formulation according to the desired function (d) method applied within the scope of the Box-Behnken design approach and RSM strategy. The cell viability and apoptosis experiments were performed on the optimized nanocarrier. In conclusion, this study demonstrates that the optimized core-shell nanoformulation of piroxicam is a more promising strategy in the treatment of prostate cancer compared to the pure molecule.

Bombax costatum enhances piroxicam's efficacy: Possible involvement of alpha-2 adrenergic receptor, opioidergic and arachidonic pathways.

BACKGROUND: With increasing drug-herb combination and widespread use of Bombax costatum as analgesic in Africa, this research studies effects of Bombax costatum on piroxicam's efficacy and possible mechanisms of antinociception. MATERIALS AND METHODS: In efficacy studies, four groups of mice were respectively treated with 1mL/kg distilled water, 400mg/kg Bombax costatum, 20mg/kg piroxicam and a combination of both. Acetic acid and hot plate were used to induce pain in mice while prostaglandin-E2 and formalin were used to induce inflammation in rats. For mechanistic studies, different groups of mice were treated intraperitoneally with 2mg/kg naloxone, 1mg/kg yohimbine, 20mg/kg propranolol, 5mg/kg glibenclamide and 1mg/kg prazosin respectively. Two other groups were treated orally with 1mL/kg of the vehicle and 400mg/kg Bombax costatum respectively. 60minutes later, 10mL/kg of 0.6% acetic acid was administered via the intraperitoneal route and number of writhes were observed for 10minutes. RESULTS: Concurrent administration of Bombax costatum and piroxicam decreased the number of writhes significantly (P≤0.001), increased reaction time with decreased paw diameter in comparison to control. Additionally, this drug-herb combination showed enhanced anti-nocipective efficacy than when administered singly. Also, pre-treatment with yohimbine and naloxone significantly (P≤0.01) inhibited the antinociceptive activities of Bombax costatum. CONCLUSION: Bombax costatum posses antinociceptive and anti-inflammatory activities and may involve α-2 adrenergic receptor, opioidergic and arachidonic pathways. In addition, Bombax costaum augments the efficacy of piroxicam and could be of clinical benefits if studied on man.

Oxicam-type non-steroidal anti-inflammatory drugs inhibit NPR1-mediated salicylic acid pathway.

Nonsteroidal anti-inflammatory drugs (NSAIDs), including salicylic acid (SA), target mammalian cyclooxygenases. In plants, SA is a defense hormone that regulates NON-EXPRESSOR OF PATHOGENESIS RELATED GENES 1 (NPR1), the master transcriptional regulator of immunity-related genes. We identify that the oxicam-type NSAIDs tenoxicam (TNX), meloxicam, and piroxicam, but not other types of NSAIDs, exhibit an inhibitory effect on immunity to bacteria and SA-dependent plant immune response. TNX treatment decreases NPR1 levels, independently from the proposed SA receptors NPR3 and NPR4. Instead, TNX induces oxidation of cytosolic redox status, which is also affected by SA and regulates NPR1 homeostasis. A cysteine labeling assay reveals that cysteine residues in NPR1 can be oxidized in vitro, leading to disulfide-bridged oligomerization of NPR1, but not in vivo regardless of SA or TNX treatment. Therefore, this study indicates that oxicam inhibits NPR1-mediated SA signaling without affecting the redox status of NPR1.

Modulating Properties of Piroxicam, Meloxicam and Oxicam Analogues against Macrophage-Associated Chemokines in Colorectal Cancer.

The mechanisms underlying the antineoplastic effects of oxicams have not been fully elucidated. We aimed to assess the effect of classic and novel oxicams on the expression/secretion of macrophage-associated chemokines (RTqPCR/Luminex xMAP) in colorectal adenocarcinoma cells, and on the expression of upstream the non-steroidal anti-inflammatory drug (NSAID)-activated genes NAG1, NFKBIA, MYD88, and RELA, as well as at the chemokine profiling in colorectal tumors. Meloxicam downregulated CCL4 9.9-fold, but otherwise the classic oxicams had a negligible/non-significant effect. Novel analogues with a thiazine ring substituted with arylpiperazine and benzoyl moieties significantly modulated chemokine expression to varying degree, upregulated NAG1 and NFKBIA, and downregulated MYD88. They inhibited CCL3 and CCL4, and their effect on CCL2 and CXCL2 depended on the dose and exposure. The propylene linker between thiazine and piperazine nitrogens and one arylpiperazine fluorine substituent characterized the most effective analogue. Only CCL19 and CXCL2 were not upregulated in tumors, nor was CXCL2 in tumor-adjacent tissue compared to normal mucosa. Compared to adjacent tissue, CCL4 and CXCL2 were upregulated, while CCL2, CCL8, and CCL19 were downregulated in tumors. Tumor CCL2 and CCL7 increased along with advancing T and CCL3, and CCL4 along with the N stage. The introduction of arylpiperazine and benzoyl moieties into the oxicam scaffold yields effective modulators of chemokine expression, which act by upregulating NAG1 and interfering with NF-κB signaling.

Combination therapy with cannabidiol and chemotherapeutics in canine urothelial carcinoma cells.

BACKGROUND: Canine urothelial carcinoma is the most common form of canine bladder cancer. Treatment with chemotherapy has variable response rates leading to most dogs succumbing to their disease within a year. Cannabidiol is an emerging treatment within the field of oncology. In reported in vivo studies, cannabidiol has induced apoptosis, reduced cell migration, and acted as a chemotherapy sensitizer in various human tumor types. The aim of this study was to characterize the effects of cannabidiol on canine urothelial carcinoma cell viability and apoptosis as both a single agent and in combination with chemotherapy in vitro. RESULTS: Cannabidiol reduced cell viability and induced apoptosis in canine urothelial cells as determined by crystal violet viability assay and annexin V/propidium iodide flow cytometry. Furthermore, combinations of cannabidiol with mitoxantrone and vinblastine chemotherapy yielded significantly reduced cell viability and increased apoptosis compared to single agent treatment alone. The drug interactions were deemed synergistic based on combination index calculations. Conversely, the combination of cannabidiol and carboplatin did not result in decreased cell viability and increased apoptosis compared to single agent treatment. Combination index calculations suggested an antagonistic interaction between these drugs. Finally, the combination of the non-steroidal anti-inflammatory drug piroxicam with cannabidiol did not significantly affect cell viability, although, some cell lines demonstrated decreased cell viability when mitoxantrone was combined with piroxicam. CONCLUSIONS: Cannabidiol showed promising results as a single agent or in combination with mitoxantrone and vinblastine for treatment of canine urothelial carcinoma cells. Further studies are justified to investigate whether these results are translatable in vivo.

Peripheral Opioid Receptor Blockade Enhances Epithelial Damage in Piroxicam-Accelerated Colitis in IL-10-Deficient Mice.

Mucosal CD4+ T lymphocytes display a potent opioid-mediated analgesic activity in interleukin (IL)-10 knockout mouse model of inflammatory bowel diseases (IBD). Considering that endogenous opioids may also exhibit anti-inflammatory activities in the periphery, we examined the consequences of a peripheral opioid receptor blockade by naloxone-methiodide, a general opioid receptor antagonist unable to cross the blood-brain barrier, on the development of piroxicam-accelerated colitis in IL-10-deficient (IL-10-/-) mice. Here, we show that IL-10-deficient mice treated with piroxicam exhibited significant alterations of the intestinal barrier function, including permeability, inflammation-related bioactive lipid mediators, and mucosal CD4+ T lymphocyte subsets. Opioid receptor antagonization in the periphery had virtually no effect on colitis severity but significantly worsened epithelial cell apoptosis and intestinal permeability. Thus, although the endogenous opioid tone is not sufficient to reduce the severity of colitis significantly, it substantially contributes to the protection of the physical integrity of the epithelial barrier.

Unique Regulation of Intestinal Villus Epithelial Cl-/HCO3- Exchange by Cyclooxygenase Pathway Metabolites of Arachidonic Acid in a Mouse Model of Spontaneous Ileitis.

Electrolytes (NaCl) and fluid malabsorption cause diarrhea in inflammatory bowel disease (IBD). Coupled NaCl absorption, mediated by Na+/H+ and Cl-/HCO3- exchanges on the intestinal villus cells brush border membrane (BBM), is inhibited in IBD. Arachidonic acid metabolites (AAMs) formed via cyclooxygenase (COX) or lipoxygenase (LOX) pathways are elevated in IBD. However, their effects on NaCl absorption are not known. We treated SAMP1/YitFc (SAMP1) mice, a model of spontaneous ileitis resembling human IBD, with Arachidonyl Trifluoro Methylketone (ATMK, AAM inhibitor), or with piroxicam or MK-886, to inhibit COX or LOX pathways, respectively. Cl-/HCO3- exchange, measured as DIDS-sensitive 36Cl uptake, was significantly inhibited in villus cells and BBM vesicles of SAMP1 mice compared to AKR/J controls, an effect reversed by ATMK. Piroxicam, but not MK-886, also reversed the inhibition. Kinetic studies showed that inhibition was secondary to altered Km with no effects on Vmax. Whole cell or BBM protein levels of Down-Regulated in Adenoma (SLC26A3) and putative anion transporter-1 (SLC26A6), the two key BBM Cl-/HCO3- exchangers, were unaltered. Thus, inhibition of villus cell Cl-/HCO3- exchange by COX pathway AAMs, such as prostaglandins, via reducing the affinity of the exchanger for Cl-, and thereby causing NaCl malabsorption, could significantly contribute to IBD-associated diarrhea.

Electrophysiological signatures of acute systemic lipopolysaccharide-induced inflammation: potential implications for delirium science.

BACKGROUND: Novel preventive therapies are needed for postoperative delirium, which especially affects older patients. A mouse model is presented that captures inflammation-associated cortical slow wave activity (SWA) observed in patients, allowing exploration of the mechanistic role of prostaglandin-adenosine signalling. METHODS: EEG and cortical cytokine measurements (interleukin 6, monocyte chemoattractant protein-1) were obtained from adult and aged mice. Behaviour, SWA, and functional connectivity were assayed before and after systemic administration of lipopolysaccharide (LPS)+piroxicam (cyclooxygenase inhibitor) or LPS+caffeine (adenosine receptor antagonist). To avoid the confounder of inflammation-driven changes in movement which alter SWA and connectivity, electrophysiological recordings were classified as occurring during quiescence or movement, and propensity score matching was used to match distributions of movement magnitude between baseline and post-LPS administration. RESULTS: LPS produces increases in cortical cytokines and behavioural quiescence. In movement-matched data, LPS produces increases in SWA (likelihood-ratio test: χ2(4)=21.51, P<0.001), but not connectivity (χ2(4)=6.39, P=0.17). Increases in SWA associate with interleukin 6 (P<0.001) and monocyte chemoattractant protein-1 (P=0.001) and are suppressed by piroxicam (P<0.001) and caffeine (P=0.046). Aged animals compared with adult animals show similar LPS-induced SWA during movement, but exaggerated cytokine response and increased SWA during quiescence. CONCLUSIONS: Cytokine-SWA correlations during wakefulness are consistent with observations in patients with delirium. Absence of connectivity effects after accounting for movement changes suggests decreased connectivity in patients is a biomarker of hypoactivity. Exaggerated effects in quiescent aged animals are consistent with increased hypoactive delirium in older patients. Prostaglandin-adenosine signalling may link inflammation to neural changes and hence delirium.

Role of PGE2 in colonic motility: PGE2 attenuates spontaneous contractions of circular smooth muscle via EP4 receptors in the rat colon.

Colonic motor activity is important for the formation and propulsion of feces. The production of prostaglandins (PGs) in colonic tissue is considered to play a critical role in the generation and regulation of colonic motility. In this study, we investigated the inhibitory effects of PGE2 and selective agonists of four EP receptors on the spontaneous phasic contractions, called 'giant contractions' (GCs), of mucosa-free circular smooth muscle strips from the rat middle colon. Neural blockade with tetrodotoxin (TTX) increased the frequency and amplitude of the GCs by about twofold. However, inhibiting PG production with piroxicam reduced the GC frequency in the presence of TTX, but did not affect the GC amplitude. In the presence of both TTX and piroxicam, exogenous PGE2 and each EP receptor agonist were cumulatively added to the tissue bath. In this setting, PGE2, the EP2 agonist ONO-AE1-259, and the EP4 agonist ONO-AE1-329, but not the EP1 agonist ONO-AE-DI-004 or the EP3 agonist ONO-AE-248, concentration-dependently reduced the GC frequency and amplitude. The PGE2-induced inhibition of GC frequency and amplitude was inhibited by the EP4 antagonist ONO-AE3-208, but not by the EP1/2 antagonist AH6809. Immunohistochemistry revealed the EP2 and EP4 receptors were localized in perinuclear sites in circular smooth muscle cells. EP2 immunoreactivity was also located in GFAP-immunoreactive enteroglia, whereas EP4 immunoreactivity was also located in HU (embryonic lethal, abnormal vision [ELAV] protein; a marker of all myenteric neurons)-immunoreactive myenteric nerve cell bodies. These results suggest that the PGs produced in the colonic tissue inhibit the GC frequency and amplitude of circular muscle in the rat middle colon, and is mediated by EP4 receptors expressed in the smooth muscle cells.