The effects of tramadol on postoperative shivering after sevoflurane and remifentanil anesthesia.

BACKGROUNDS: Remifentanil has been reported to cause post-anesthetic shivering (PAS). Higher doses of remifentanil reportedly induce more intense PAS. Tramadol, a synthetic opioid that acts at multiple sites, is considered to be an effective treatment for PAS, but the evidence for its therapeutic benefit after remifentanil anesthesia is limited. We investigated the effect of tramadol on the incidence of PAS after remifentanil anesthesia. METHODS: Sixty-three patients who had undergone upper abdominal surgery under general anesthesia were studied retrospectively. Tramadol was administered at induction of anesthesia. The patients were divided into four groups: HT(+), high dose remifentanil (1-1.5 µg/kg/min) with tramadol; HT(-), high dose remifentanil without tramadol; LT(+), low dose remifentanil (0.15-0.25 µg/kg/min) with tramadol; and LT(-), low dose remifentanil without tramadol. We recorded perioperative changes in nasopharyngeal temperature and episodes of PAS on emergence from anesthesia. RESULTS: The incidences of PAS in both tramadol treatment groups were significantly lower than the groups that did not receive tramadol. Nasopharyngeal temperature after surgery fell significantly more from baseline in the tramadol treatment groups compared with the non-treatment groups. CONCLUSION: Tramadol administered at induction of anesthesia appears to suppress PAS following remifentanil anesthesia.

A comparison of intrathecal magnesium and ketamine in attenuating remifentanil-induced hyperalgesia in rats.

BACKGROUND: Activation of NMDA receptors play an important role in the development of remifentanil-induced hyperalgesia. We hypothesized that in addition to ketamine, intrathecal MgSO4 could also relieve thermal and mechanical hyperalgesia in rats. METHODS: Initially, 24 Sprague-Dawley rats were divided into control group, remifentanil group, surgical incision group and remifentanil combined with surgical incision group to create an experimental model. Subsequently, 40 rats were divided into control group, model group, model group plus 100 µg MgSO4, 300 µg MgSO4 and 10 µg ketamine respectively. Paw withdrawal mechanical thresholds and paw withdrawal thermal latency tests were performed at -24 h, 2 h, 6 h, 24 h, 48 h, 72 h and 7 day after the surgical procedure. After behavior assessment on the 7th day, remifentanil was given again to ascertain whether or not NMDA antagonists could suppress the re-exposure of remifentanil-induced hyperalgesia. RESULTS: Remifentanil administration plus surgical incision induced significant postoperative hyperalgesia, as indicated by decreased paw withdrawal mechanical thresholds and paw withdrawal thermal latency to mechanical and thermal stimulation. In addition to ketamine, intrathecal MgSO4 (100, 300 µg) dose-dependently reduced remifentanil-induced mechanical and thermal hyperalgesia. Ketamine had less mechanical hyperalgesia in 6 h (p = 0.018), 24 h (p = 0.014) and 48 h (p = 0.011) than 300 µg MgSO4. There was no difference in inhibiting thermal hyperalgesia between the group ketamine and group MgSO4 (300 µg). The rats were given remifentanil again 7 days later after the first exposure of remifentanil. The hyperalgesic effect induced by re-exposure of remifentanil was not reversed in any groups of MgSO4 or ketamine. CONCLUSIONS: In addition to ketamine, intrathecal administration of MgSO4 dose-dependently reduced remifentanil-induced hyperalgesia in a surgical incision mode. Re-exposure to remifentanil 1 week later again produced hyperalgesia, and this was not altered by the prior intrathecal treatments in any 4 groups treated with MgSO4 or ketamine.

Neuroprotective effects of three different sizes nanochelating based nano complexes in MPP(+) induced neurotoxicity.

Parkinson's disease (PD) is the world's second most common dementia, which the drugs available for its treatment have not had effects beyond slowing the disease process. Recently nanotechnology has induced the chance for designing and manufacturing new medicines for neurodegenerative disease. It is demonstrated that by tuning the size of a nanoparticle, the physiological effect of the nanoparticle can be controlled. Using novel nanochelating technology, three nano complexes: Pas (150 nm), Paf (100 nm) and Pac (40 nm) were designed and in the present study their neuroprotective effects were evaluated in PC12 cells treated with 1-methyl-4-phenyl-pyridine ion (MPP (+)). PC12 cells were pre-treated with the Pas, Paf or Pac nano complexes, then they were subjected to 10 µM MPP (+). Subsequently, cell viability, intracellular free Calcium and reactive oxygen species (ROS) levels, mitochondrial membrane potential, catalase (CAT) and superoxide dismutase (SOD) activity, Glutathione (GSH) and malondialdehyde (MDA) levels and Caspase 3 expression were evaluated. All three nano complexes, especially Pac, were able to increase cell viability, SOD and CAT activity, decreased Caspase 3 expression and prevented the generation of ROS and the loss of mitochondrial membrane potential caused by MPP(+). Pre-treatment with Pac and Paf nano complexes lead to a decrease of intracellular free Calcium, but Pas nano complex could not decrease it. Only Pac nano complex decreased MDA levels and other nano complexes could not change this parameter compared to MPP(+) treated cells. Hence according to the results, all nanochelating based nano complexes induced neuroprotective effects in an experimental model of PD, but the smallest nano complex, Pac, showed the best results.

Use of Remifentanil in a Novel Clinical Paradigm to Characterize Onset and Duration of Opioid Blockade by Samidorphan, a Potent µ-Receptor Antagonist.

A novel clinical study design was used to evaluate the blockade of a selective short-acting µ-opioid agonist (remifentanil) in 24 opioid-experienced subjects. Samidorphan (3-carboxamido-4-hydroxynaltrexone) is a novel opioid modulator with µ-antagonist properties. Objective (pupil diameter) and subjective (visual analog scale) responses to repeated remifentanil and saline infusion challenges were assessed after single oral administration of placebo (day 1) and samidorphan (day 2). Complete blockade persisted with samidorphan for 24 hours for pupil miosis and 48 hours for the drug liking visual analog scale. Samidorphan effects persisted beyond measurable samidorphan exposure (t½ = 7 hours). Samidorphan was associated with complete blockade of remifentanil, and the duration supports daily administration. This study used a novel approach with multiple administrations of remifentanil to successfully demonstrate a durable effect with samidorphan and a rapid and potent blockade of physiological and subjective µ-opioid effects.

Analgesic effect of GT-0198, a structurally novel glycine transporter 2 inhibitor, in a mouse model of neuropathic pain.

This study was conducted to identify the characteristic pharmacological features of GT-0198 that is phenoxymethylbenzamide derivatives. GT-0198 inhibited the function of glycine transporter 2 (GlyT2) in human GlyT2-expressing HEK293 cells and did not bind various major transporters or receptors of neurotransmitters in a competitive manner. Thus, GT-0198 is considered to be a comparatively selective GlyT2 inhibitor. Intravenous, oral, and intrathecal injections of GT-0198 decreased the pain-related response in a model of neuropathic pain with partial sciatic nerve ligation. This result suggests that GT-0198 has an analgesic effect. The analgesic effect of GT-0198 was abolished by the intrathecal injection of strychnine, a glycine receptor antagonist. Therefore, GT-0198 is considered to exhibit its analgesic effect via the activation of a glycine receptor by glycine following presynaptic GlyT2 inhibition in the spinal cord. In summary, GT-0198 is a structurally novel GlyT2 inhibitor bearing a phenoxymethylbenzamide moiety with in vivo efficacy in behavioral models of neuropathic pain.

High-Concentration Piperine: Capsaicin-Sensitive and -Insensitive Effects on Isolated Organs.

Piperine (P), a sensory stimulant in black pepper, is an agonist on TRPV1 receptors. Earlier work has showed capsaicin-sensitive and -insensitive mechanisms of the contractile action of P on the intestine. The current isolated organ study in the guinea-pig ileum, urinary bladder and trachea (a) confirms the presence of such components of effect (ileum and bladder); (b) indicates TRPV1 involvement in the effect of 5 or 30 µmol/l of P on the basis of an inhibitory action of the antagonist BCTC (ileum); (c) indicates that HC 030031-sensitive TRPA1 receptors and nifedipine-sensitive Ca(2+) channels contribute to the capsaicin-resistant contraction to 30 µmol/l P (ileum) and (d) shows that the contractile effect of P up to 100 µmol/l (guinea-pig trachea) or 30 µmol/l (guinea-pig urinary bladder) is capsaicin-sensitive and mediated by TRPV1 receptors/channels.

Glycogen synthase kinase-3ß inhibition prevents remifentanil-induced postoperative hyperalgesia via regulating the expression and function of AMPA receptors.

BACKGROUND: Many studies have confirmed that brief remifentanil exposure can enhance pain sensitivity. We previously reported that activation of glycogen synthase kinase-3ß (GSK-3ß) contributes to remifentanil-induced hyperalgesia via regulating N-methyl-D-aspartate receptor plasticity in the spinal dorsal horn. In this study, we demonstrated that GSK-3ß inhibition prevented remifentanil-induced postoperative hyperalgesia via regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) expression and function in the spinal dorsal horn. METHODS: Using a rat model of remifentanil-induced incision hyperalgesia, mechanical and thermal pain was tested 1 day before infusion and 2 hours, 6 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after infusion. Western blot analysis was used to detect AMPAR subunit (GluR1 and GluR2) trafficking, AMPAR phosphorylation status, and GSK-3ß activity in the spinal dorsal horn. Furthermore, whole-cell patch-clamp recording was used to analyze the effect of GSK-3ß inhibition on AMPAR-induced current in the spinal dorsal horn. RESULTS: Membrane AMPAR subunit GluR1 was upregulated in the spinal cord in remifentanil-induced postoperative hyperalgesia rats (275 ± 36.54 [mean ± SD] vs 100 ± 9.53, P = 0.0009). Selective GSK-3ß inhibitors, LiCl and TDZD, treatment ameliorates remifentanil-induced postoperative hyperalgesia, and this was associated with the downregulated GluR1 subunit in the membrane fraction (254 ± 23.51 vs 119 ± 14.74, P = 0.0027; 254 ± 23.51 vs 124 ± 9.35, P = 0.0032). Moreover, remifentanil incubation increased the amplitude and the frequency of AMPAR-induced current in dorsal horn neurons (61.09 ± 9.34 pA vs 32.56 ± 6.44 pA, P = 0.0009; 118.32 ± 20.33 milliseconds vs 643.67 ± 43.29 milliseconds, P = 0.0002), which was prevented with the application of LiCl and TDZD, respectively. Remifentanil-induced postoperative pain induced an increase in pGluR1 Ser845 and Rab5, which was prevented with the application of LiCl and TDZD. CONCLUSIONS: These results indicate that amelioration of remifentanil-induced postoperative hyperalgesia by GSK-3ß inhibition is attributed to downregulated AMPAR GluR1 expression in the membrane fraction and inhibition of AMPAR function via altering pGluR1 and Rab5 expression in the spinal dorsal horn.

Intrathecal injection of JWH015 attenuates remifentanil-induced postoperative hyperalgesia by inhibiting activation of spinal glia in a rat model.

BACKGROUND: Hyperalgesia and neuroinflammation are associated with glia, which consists of macroglia and microglia. In this study, we used a selective cannabinoid receptor type 2 (CB2) agonist JWH015 to investigate remifentanil-induced postoperative hyperalgesia. METHODS: Mechanical allodynia and thermal hyperalgesia after postoperative hyperalgesia and intrathecal injection of JWH015 were assessed by the paw withdrawal mechanical threshold and paw withdrawal thermal latency tests. We used immunohistochemistry and immunoblotting to investigate the effect of JWH015 on CB2 receptor, NR2B subunits, activated glial cells, and proinflammatory cytokine expression in rats after remifentanil-induced postoperative hyperalgesia. RESULTS: Postoperative hyperalgesia was induced by intraoperative infusion of remifentanil. Glial cells were activated, and expression levels of several genes were significantly increased, including interleukin 6, tumor necrosis factor α, CB2, and the NR2B subunit phosphorylated at Tyr-1472 (p-NR2B). Intrathecal injection of JWH015 significantly inhibited glial cell activation, suppressed expression of interleukin 6, tumor necrosis factor α, and p-NR2B, and stimulated CB2 expression, thus attenuating postoperative hyperalgesia. However, these phenomena were abolished in the group that was preadministered with AM630. CONCLUSIONS: The activation of glia, the production of proinflammatory cytokines, and the expression of CB2 and p-NR2B in the spinal dorsal horn increase significantly during the process of remifentanil-induced hyperalgesia. These changes can be regulated by pretreatment with JWH015, which may be the main mechanism underlying the antihyperalgesia effects of JWH015.

Fetal muscle-type nicotinic acetylcholine receptor activation in TE-671 cells and inhibition of fetal movement in a day 40 pregnant goat model by optical isomers of the piperidine alkaloid coniine.

Coniine is an optically active toxic piperidine alkaloid and nicotinic acetylcholine receptor (nAChR) agonist found in poison hemlock (Conium maculatum L.). Coniine teratogenicity is hypothesized to be attributable to the binding, activation, and prolonged desensitization of fetal muscle-type nAChR, which results in the complete inhibition of fetal movement. However, pharmacological evidence of coniine actions at fetal muscle-type nAChR is lacking. The present study compared (-)-coniine, (+)-coniine, and nicotine for the ability to inhibit fetal movement in a day 40 pregnant goat model and in TE-671 cells that express fetal muscle-type nAChR. Furthermore, α-conotoxins (CTx) EI and GI were used to antagonize the actions of (+)- and (-)-coniine in TE-671 cells. (-)-Coniine was more effective at eliciting electrical changes in TE-671 cells and inhibiting fetal movement than was (+)-coniine, suggesting stereoselectivity by the receptor. The pyridine alkaloid nicotine did not inhibit fetal movement in a day 40 pregnant goat model, suggesting agonist specificity for the inhibition of fetal movement. Low concentrations of both CTxs potentiated the TE-671 cell response and higher concentrations of CTx EI, and GI antagonized the actions of both coniine enantiomers demonstrating concentration-dependent coagonism and selective antagonism. These results provide pharmacological evidence that the piperidine alkaloid coniine is acting at fetal muscle-type nAChR in a concentration-dependent manner.

Effects of remifentanil on the esophagogastric junction and swallowing.

BACKGROUND: A recent study demonstrated that reflux is associated with impaired pressure augmentation in the esophagogastric junction (EGJ), caused by diaphragmal contractions during inspiration. It is unknown whether this augmentation is influenced by opioids. Swallowing difficulties can be a poorly recognised side effect of remifentanil. Here, we investigated whether remifentanil influences inspiratory EGJ augmentation and evaluated subjective swallowing difficulties induced by remifentanil. We also used the peripheral opioid receptor antagonist methylnaltrexone to evaluate whether these effects are centrally or peripherally mediated. METHODS: Ten healthy volunteers participated in a double-blind, randomised, cross-over trial at the University Hospital in Örebro, Sweden. They were studied on two different occasions, during which they were randomly assigned to receive either methylnaltrexone 0.15 mg/kg or saline subcutaneously 30 min before the target-controlled infusion of remifentanil of 3 ng/mL. EGJ pressures were measured by high-resolution manometry. Swallowing difficulties were assessed when volunteers performed dry swallows. The outcomes were the differences in EGJ pressures at baseline and during remifentanil infusion and with methylnaltrexone vs. placebo. Differences in swallowing difficulties before and during remifentanil, and with methylnaltrexone vs. placebo were also recorded. RESULTS: Remifentanil decreased the inspiratory EGJ augmentation and induced swallowing difficulties. No statistically significant differences between methylnaltrexone and placebo occasions were found. CONCLUSIONS: Remifentanil may increase risk for gastroesophageal reflux by decreasing the inspiratory EGJ augmentation. The clinical significance of remifentanil-induced swallowing difficulties is to be studied further. Given the limited sample size, it cannot be concluded whether these effects are centrally or peripherally mediated.

Acetylcholinesterase inhibitors attenuate angiogenesis.

Donepezil {(RS)-2-[(1-benzyl-4-piperidyl)methyl]-5,6-dimethoxy-2,3-dihydroinden-1-one} is a reversible acetylcholinesterase inhibitor and used for treatment of patients with AD (Alzheimer's disease). Recent studies showed that treatment with donepezil reduced production of inflammatory cytokines in PBMCs (peripheral blood mononuclear cells). It was also reported that muscle-derived inflammatory cytokines play a critical role in neovascularization in a hindlimb ischaemia model. We sought to determine whether donepezil affects angiogenesis. A hindlimb ischaemia model was created by unilateral femoral artery ligation. Blood flow recovery examined by laser Doppler perfusion imaging and capillary density by immunohistochemical staining of CD31-positive cells in the ischaemic hindlimb were significantly decreased in donepezil- and physostigmine-treated mice compared with control mice after 2 weeks. Donepezil reduced expression of IL (interleukin)-1ß and VEGF (vascular endothelial growth factor) in the ischaemic hindlimb. Intramuscular injections of IL-1ß to the ischaemic hindlimb reversed the donepezil-induced VEGF down-regulation and the anti-angiogenic effect. Hypoxia induced IL-1ß expression in C2C12 myoblast cells, which was inhibited by pre-incubation with ACh (acetylcholine) or LY294002, a PI3K (phosphoinositide 3-kinase) inhibitor. Donepezil inhibited phosphorylation of Akt [also known as PKB (protein kinase B)], a downstream kinase of PI3K, in the ischaemic hindlimb. These findings suggest that cholinergic stimulation by acetylcholinesterase inhibitors suppresses angiogenesis through inhibition of PI3K-mediated IL-1ß induction, which is followed by reduction of VEGF expression. Acetylcholinesterase inhibitor may be a novel anti-angiogenic therapy.

Selective 5-HT(1A)-R-agonist repinotan prevents remifentanil-induced ventilatory depression and prolongs antinociception.

BACKGROUND: 5-HT(1A)-R-agonist repinotan was shown to counteract a morphine-induced ventilatory depression but had pronociceptive effects at small doses (0.2 µg/kg). It remained to be clarified (1) whether a moderate dose of repinotan, sufficient to stimulate spontaneous breathing, impairs antinociception if plasma concentration decreases over time, and if (2) moderate doses prevent ventilatory depression if given before the opioid. METHODS: A dose-response curve of the repinotan effects on spontaneous minute ventilation during continuous remifentanil infusion in anesthetized rats was established to identify moderate doses: (1) tail-flick reflex latencies to assess nociception were recorded until 60 min after cessation of a continuous remifentanil infusion with or without a concomitant moderate repinotan dose (10 µg/kg), and (2) remifentanil boluses (2.5 µg/kg) were given after repinotan (10 and 20 µg/kg). RESULTS: (1) Remifentanil-induced antinociception lasted only 5 min after infusion was stopped (tail-flick reflex latencies; median [interquartile range], 97 [54-100]% of maximum possible effect; P = 0.034), but was extended by repinotan (10 µg/kg) to 30 min (tail-flick reflex latencies, 100 [75-100]% of maximum possible effect; P = 0.031). Repinotan (10 µg/kg) alone did not have any significant antinociceptive effect. (2) The ventilatory depression by remifentanil boluses (2.5 µg/kg; minute ventilation, -65 [-81 to -56]%; P = 0.031, n = 5) was blunted by repinotan (20 µg/kg; minute ventilation, -24 [-53 to 13]%; P = 0.313, compared with the pretreatment level). CONCLUSIONS: Repinotan prevented remifentanil-induced ventilatory depression in spontaneously breathing, anesthetized rats. Although repinotan did not depress nociception itself, it prolonged the profound antinociception after discontinuation of remifentanil infusion.

Buprenorphine/naloxone inhibition of remifentanil procedural sedation.

Opioid analgesics are the mainstay of treatment of moderate and severe pain. Remifentanil is an ultrashort acting opioid analgesic used in emergency department (ED)procedural sedation, whereas buprenorphine/naloxone (Suboxone) is an opioid agonist-antagonist combination used in the treatment of addiction-prone individuals. We report here a case of buprenorphine/naloxone inhibition of remifentanil analgesia in a patient undergoing ED procedural sedation.

Reciprocal potentiation of the antitumoral activities of FK866, an inhibitor of nicotinamide phosphoribosyltransferase, and etoposide or cisplatin in neuroblastoma cells.

NAD is an essential coenzyme involved in numerous metabolic pathways. Its principal role is in redox reactions, and as such it is not heavily "consumed" by cells. Yet a number of signaling pathways that bring about its consumption have recently emerged. This has brought about the hypothesis that the enzymes that lead to its biosynthesis may be targets for anticancer therapy. In particular, inhibition of the enzyme nicotinamide phosphoribosyl transferase has been shown to be an effective treatment in a number of preclinical studies, and two lead molecules [N-[4-(1-benzoyl-4-piperidinyl)butyl]-3-(3-pyridinyl)-2E-propenamide (FK866) and (E)-1-[6-(4-chlorophenoxy)hexyl]-2-cyano-3-(pyridin-4-yl)guanidine (CHS 828)] have now entered preclinical trials. Yet, the full potential of these drugs is still unclear. In the present study we have investigated the role of FK866 in neuroblastoma cell lines. We now confirm that FK866 alone in neuroblastoma cells induces autophagy, and its effects are potentiated by chloroquine and antagonized by 3-methyladenine or by down-regulating autophagy-related protein 7. Autophagy, in this model, seems to be crucial for FK866-induced cell death. On the other hand, a striking potentiation of the effects of cisplatin and etoposide is given by cotreatment of cells with ineffective concentrations of FK866 (1 nM). The effect of etoposide on DNA damage is potentiated by FK866 treatment, whereas the effect of FK866 on cytosolic NAD depletion is potentiated by etoposide. Even more strikingly, cotreatment with etoposide/cisplatin and FK866 unmasks an effect on mitochondrial NAD depletion.

Magnesium sulfate prevents remifentanil-induced postoperative hyperalgesia in patients undergoing thyroidectomy.

BACKGROUND: In a randomized, double-blind, prospective study, we investigated whether an intraoperative high versus low dose of remifentanil increased postoperative hyperalgesia and whether magnesium can prevent remifentanil-induced hyperalgesia. METHODS: Ninety patients undergoing thyroidectomy were randomly assigned to 1 of 3 groups. Remifentanil was intraoperatively infused at 0.05 µg/kg/min (group LO) or 0.2 µg/kg/min (groups HI and HM). Patients in group HM received MgSO(4) 30 mg/kg at induction followed by an intraoperative infusion of 10 mg/kg/h. Mechanical pain thresholds on the forearm and periincisional area were assessed by von Frey filament the evening before surgery and postoperatively at 24 and 48 hours. Pain measured on a verbal numerical rating scale (VNRS) (0-10) and additional analgesics were recorded in the postanesthesia care unit postoperatively at 6, 24, and 48 hours. RESULTS: There was a significantly greater decrease in pain threshold on the periincisional area at 24 and 48 hours postoperatively in group HI, as compared with the other 2 groups. The 95% confidence intervals for the mean difference in pain thresholds on the periincisional area at 24 and 48 hours postoperatively were 0.31 to 1.11 and 0.36 to 1.14 for group HI versus group LO, 0.45 to 1.26 and 0.54 to 1.32 for group HI versus group HM (values are log(10) of force in milligrams). The change in pain threshold on the forearm was similar among the groups. Group HI had significantly higher VNRS scores (median [interquartile range], 3 [2-4]) than group LO (2 [1-3] and group HM (2 [1-3]) at 48 hours postoperatively. The 95% confidence intervals for median difference in VNRS score at 48 hours postoperatively were 1 to 2 for group HI versus group LO and 0 to 2 for group HI versus group HM. There were no significant differences in the number of patients who requested rescue analgesics in the postoperative anesthesia care unit and general ward during 48 hours postoperatively among the 3 groups. CONCLUSIONS: A relatively high dose of intraoperative remifentanil enhances periincisional hyperalgesia. Intraoperative MgSO(4) prevents remifentanil-induced hyperalgesia. However, hyperalgesia did not reach clinical relevance in terms of postoperative pain or analgesic consumption in patients undergoing thyroidectomy.

Additive actions of the cannabinoid and neuropeptide Y systems on adiposity and lipid oxidation.

AIMS: Energy homeostasis is regulated by a complex interaction of molecules and pathways, and new antiobesity treatments are likely to require multiple pharmacological targeting of anorexigenic or orexigenic pathways to achieve effective loss of excess body weight and adiposity. Cannabinoids, acting via the cannabinoid-1 (CB1) receptor, and neuropeptide Y (NPY) are important modulators of feeding behaviour, energy metabolism and body composition. We investigated the interaction of CB1 and NPY in the regulation of energy homeostasis, hypothesizing that dual blockade of CB1 and NPY signalling will induce greater weight and/or fat loss than that induced by single blockade of either system alone. METHODS: We studied the effects of the CB1 antagonist Rimonabant on food intake, body weight, body composition, energy metabolism and bone physiology in wild-type (WT) and NPY knockout (NPY(-/-)) mice. Rimonabant was administered orally at 10 mg/kg body weight twice per day for 3 weeks. Oral Rimonabant was delivered voluntarily to mice via a novel method enabling studies to be carried out in the absence of gavage-induced stress. RESULTS: Mice with dual blockade of CB1 and NPY signalling (Rimonabant-treated NPY(-/-) mice) exhibited greater reductions in body weight and adiposity than mice with single blockade of either system alone (Rimonabant-treated WT or vehicle-treated NPY(-/-) mice). These changes occurred without loss of lean tissue mass or bone mass. Furthermore, Rimonabant-treated NPY(-/-) mice showed a lower respiratory exchange ratio than that seen in Rimonabant-treated WT or vehicle-treated NPY(-/-) mice, suggesting that this additive effect of dual blockade of CB1 and NPY involves promotion of lipid oxidation. On the other hand, energy expenditure and physical activity were comparable amongst all treatment groups. Interestingly, Rimonabant similarly and transiently reduced spontaneous and fasting-induced food intake in WT and NPY(-/-) mice in the first hour after administration only, suggesting independent regulation of feeding by CB1 and NPY signalling. In contrast, Rimonabant increased serum corticosterone levels in WT mice, but this effect was not seen in NPY(-/-) mice, indicating that NPY signalling may be required for effects of CB1 on the hypothalamo-pituitary-adrenal axis. CONCLUSIONS: Dual blockade of CB1 and NPY signalling leads to additive reductions in body weight and adiposity without concomitant loss of lean body mass or bone mass. An additive increase in lipid oxidation in dual CB1 and NPY blockade may contribute to the effect on adiposity. These findings open new avenues for more effective treatment of obesity via dual pharmacological manipulations of the CB1 and NPY systems.

Design and Synthesis of TASIN Analogues Specifically Targeting Colorectal Cancer Cell Lines with Mutant Adenomatous Polyposis Coli (APC).

Despite advances in targeted anticancer therapies, there are still no small-molecule-based therapies available that specifically target colorectal cancer (CRC) development and progression, the second leading cause of cancer deaths. We previously disclosed the discovery of truncating adenomatous polyposis coli (APC)-selective inhibitor 1 (TASIN-1), a small molecule that specifically targets colorectal cancer cells lines with truncating mutations in the adenomatous polyposis coli (APC) tumor suppressor gene through inhibition of cholesterol biosynthesis. Here, we report a medicinal chemistry evaluation of a collection of TASIN analogues and activity against colon cancer cell lines and an isogenic cell line pair reporting on the status of APC-dependent selectivity. A number of potent and selective analogues were identified, including compounds with good metabolic stability and pharmacokinetic properties. The compounds reported herein represent a first-in-class genotype-selective series that specifically target apc mutations present in the majority of CRC patients and serve as a translational platform toward a targeted therapy for colon cancer.

Nicotinamide phosphoribosyltransferase­related signaling pathway in early Alzheimer's disease mouse models.

Alzheimer's disease (AD) is a neurodegenerative disease of the central nervous system that is characterized by progressive cognitive dysfunction and which ultimately leads to dementia. Studies have shown that energy dysmetabolism contributes significantly to the pathogenesis of a variety of aging­associated diseases and degenerative diseases of the nervous system, including AD. One focus of research thus has been how to regulate the expression of nicotinamide phosphoribosyltransferase (NAMPT) to prevent against neurodegenerative diseases. Therefore, the present study used 6­month­old APPswe/PS1ΔE9 (APP/PS1) transgenic mice as early AD mouse models and sought to evaluate nicotinamide adenine dinucleotide (NAD+) and FK866 (a NAMPT inhibitor) treatment in APP/PS1 mice to study NAMPT dysmetabolism in the process of AD and elucidate the underlying mechanisms. As a result of this treatment, the expression of NAMPT decreased, the synthesis of ATP and NAD+ became insufficient and the NAD+/NADH ratio was reduced. The administration of NAD+ alleviated the spatial learning and memory of APP/PS1 mice and reduced senile plaques. Administration of NAD+ may also increase the expression of the key protein NAMPT and its related protein sirtuin 1 as well as the synthesis of NAD+. Therefore, increasing NAMPT expression levels may promote NAD+ production. Their regulation could form the basis for a new therapeutic strategy.

Analysis of promoter regions regulating basal and interleukin-4-inducible expression of the human CB1 receptor gene in T lymphocytes.

The majority of effects of cannabinoids are mediated by the two receptors CB1 and CB2. In addition to neuronal cells, CB1 receptors are expressed in T lymphocytes, in which they are involved in cannabinoid-induced T helper cell biasing. Although basally expressed only weakly in T cells, CB1 receptors are up-regulated in these cells by stimuli such as cannabinoids themselves. This effect is mediated by interleukin-4. In this study, we investigated basal and interleukin-4-inducible expression of the CB1 gene in T lymphocytes. In a promoter analysis, two regions [nucleotides (nts) -3086 to -2490 and nts -1950 to -1653] were identified, which suppress basal transcription of the gene in Jurkat T cells, whereas the region between nts -648 and -559 enhanced basal CB1 transcription. Interleukin-4 markedly induced transcription of CB1 in Jurkat cells and primary human T cells. Experiments using transcription factor decoy oligonucleotides demonstrated that STAT6 mediates regulation of the gene by interleukin-4. Using reporter gene assays and the transcription factor decoy oligonucleotide approach, a binding site for STAT6 was identified at nt -2769 on the human CB1 gene promoter. Interleukin-4 also caused up-regulation of functional CB1 receptor proteins. In interleukin-4 pretreated, but not in naive Jurkat cells, the CB1 agonist R(+)-methanandamide caused a significant inhibition of forskolin-induced cAMP formation. This effect was blocked by the CB1-selective antagonists N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) and 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-mo rpholinyl-1H-pyrazole-3-carboxamide (AM281). Taken together, these data show that CB1 receptors are expressed and up-regulated by interleukin-4 in T lymphocytes, which enables CB1-mediated communication to cells of other systems, such as neuronal cells.

[Balanced anesthesia with continuous ketamine reduces adverse effects of remifentanil].

BACKGROUND: We evaluated the use of continuous infusion of ketamine to reduce intraoperative remifentanil side effects, such as bradycardia and hypotension, and to improve postoperative analgesia from balanced anesthesia with remifentanil. METHODS: Forty patients undergoing spine surgery under remifentanil-based anesthesia were randomly assigned to intraoperative ketamine group and saline (control) group. Balanced anesthesia was maintained with infusion of propofol (2-4 mg x kg(-1) x hr(-1)), remifentanil (6-8 microg x kg(-1) hr(-1)) and vecuronium (60-80 microg x kg(-1) x hr(-1)) with nitrous oxide (60%) and with or without ketamine (300-400 microg x kg(-1) x hr(-)). All patients were given scheduled NSAIDs by their own doctor at the end of surgery. Intraoperative bradycardia (HR <50) and hypotension (SBP <80), and postoperative additional NSAIDs request were recorded. RESULTS: Adverse events, such as bradycardia and hypotension, were less frequent in the ketamine group (P < 0.05). Less additional NSAIDs was required in the ketamine than in the control group (P < 0.05). Emergence time from anesthesia was within 5 min in both groups. CONCLUSIONS: Remifentanil-based anesthesia with continuous ketamine decreases intraoperative side effects and postoperative NSAIDs request. Thus, intraoperative continuous ketamine may be a useful adjuvant to remifentanil.