piperidines and nimesulide

Recent studies suggest that the effects of cyclooxygenase-2 (COX-2) inhibition are mediated by cannabinoid receptor activation. However, some non-steroidal anti-inflammatory drugs inhibit the enzyme fatty acid amide hydrolase, which regulates levels of some endocannabinoids. Whether COX-2 directly regulates levels of endocannabinoids in vivo is unclear. Here, the effect of the COX-2 inhibitor nimesulide, which does not inhibit fatty acid amide hydrolase, on spinal nociceptive processing was determined. Effects of nimesulide on tissue levels of endocannabinoids and related compounds were measured and the role of cannabinoid 1 (CB(1)) receptors was determined.. Effects of spinal and peripheral administration of nimesulide (1-100 microg per 50 microL) on mechanically evoked responses of rat dorsal horn neurones were measured, and the contribution of the CB(1) receptor was determined with the antagonist AM251 (N-(piperidin-1-yl)-5-(-4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide), in anaesthetized rats. Effects of nimesulide on spinal levels of endocannabinoids and related compounds were quantified using liquid chromatography-tandem mass spectrometry.. Spinal, but not peripheral, injection of nimesulide (1-100 microg per 50 microL) significantly reduced mechanically evoked responses of dorsal horn neurones. Inhibitory effects of spinal nimesulide were blocked by the CB(1) receptor antagonist AM251 (1 microg per 50 microL), but spinal levels of endocannabinoids were not elevated. Indeed, both anandamide and N-oleoylethanolamide (OEA) were significantly decreased by nimesulide.. Although the inhibitory effects of COX-2 blockade on spinal neuronal responses by nimesulide were dependent on CB(1) receptors, we did not detect a concomitant elevation in anandamide or 2-AG. Further understanding of the complexities of endocannabinoid catabolism by multiple enzymes is essential to understand their contribution to COX-2-mediated analgesia.

Topics: Animals; Cannabinoid Receptor Modulators; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Drug Administration Routes; Endocannabinoids; Evoked Potentials; Male; Pain; Piperidines; Posterior Horn Cells; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Spinal Cord; Sulfonamides

Opioid-induced vasodepressor responses have been reported in a variety of species and laboratory models. The aim of this study was to ascertain the relative potencies of different clinically relevant opioids compared with traditional vasodepressor agents in the feline pulmonary vascular bed. A second aim was to study the effects of morphine and to identify the receptors involved in the mediation or the modulation of these effects.. This was a prospective vehicle-controlled study involving an intact chest preparation of adult mongrel cats. The effects of various opioids, morphine, fentanyl, remifentanil, sufentanil, and meperidine were compared with other vasodepressor agents. Additionally, the effects of L-N(5)-(1-iminoethyl) ornithine hydrochloride (L-NIO) (nitric oxide synthase inhibitor), nimesulide [selective cyclooxygenase (COX)-2 inhibitor], glibenclamide (ATP-sensitive K+ channel blocker), naloxone (non-selective opioid receptor antagonist), and diphenhydramine (histamine H(1)-receptor antagonist) were investigated on pulmonary arterial responses to morphine and other selected agonists in the feline pulmonary vascular bed. The systemic pressure and lobar arterial perfusion pressure were continuously monitored, electronically averaged, and recorded.. In the cat pulmonary vascular bed of the isolated left lower lobe, morphine, remifentanil, fentanyl, sufentanil, and meperidine induced a dose-dependent moderate vasodepressor response and it appeared that sufentanil was the most potent on a nanomolar basis. The effects of morphine were not significantly altered after administration of L-NIO, nimesulide, and glibenclamide. However, the vascular responses to morphine were significantly attenuated following administration of naloxone and diphenhydramine.. The results of the present study suggest that sufentanil appears to have slightly more potency and morphine the least of the five opioid agonists studied on a nanomolar basis. Morphine-induced vasodilatory responses appeared to be mediated or modulated by both opioid receptor and histamine-receptor-sensitive pathways.

Topics: Analgesics, Opioid; Animals; Blood Pressure; Cats; Diphenhydramine; Dose-Response Relationship, Drug; Drug Interactions; Female; Fentanyl; Glyburide; Lung; Male; Meperidine; Morphine; Naloxone; Ornithine; Piperidines; Prospective Studies; Pulmonary Artery; Pulmonary Circulation; Remifentanil; Sufentanil; Sulfonamides; Vasodilation; Vasodilator Agents

In hippocampal pyramidal cells, a rise in Ca(2+) releases endocannabinoids that activate the presynaptic cannabinoid receptor (CB1R) and transiently reduce GABAergic transmission-a process called depolarization-induced suppression of inhibition (DSI). The mechanism that limits the duration of endocannabinoid action in intact cells is unknown. Here we show that inhibition of cyclooxygenase-2 (COX-2), not fatty acid amide hydrolase (FAAH), prolongs DSI, suggesting that COX-2 limits endocannabinoid action.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Cannabinoid Receptor Modulators; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Drug Synergism; Endocannabinoids; Enzyme Inhibitors; Glycerides; Hippocampus; In Vitro Techniques; Isoenzymes; Male; Meloxicam; Membrane Potentials; Neural Inhibition; Patch-Clamp Techniques; Piperidines; Polyunsaturated Alkamides; Prostaglandin-Endoperoxide Synthases; Pyramidal Cells; Pyrazoles; Rats; Rats, Sprague-Dawley; Sulfonamides; Thiazines; Thiazoles

Chronic treatment with opioid drugs such as morphine leads to the development of tolerance, which manifests as a loss of drug potency. The mechanisms underlying this phenomenon are poorly understood, but recent evidence suggests that increased activity of nociceptive sensory transmitters [calcitonin gene-related peptide (CGRP) and substance P] and other signalling messengers (prostaglandins) contribute to its development. Chronic intrathecal morphine administration to rats for 7 days produced analgesic tolerance. Co-administration of SR140333, a selective substance P receptor (neurokinin-1) antagonist, or nimesulide, a cyclooxygenase-2-selective inhibitor, augmented the acute effects of morphine, prevented morphine tolerance and reversed established tolerance. In cultured adult dorsal root ganglion neurons, exposure to morphine for 5 days increased the number of neurons expressing CGRP immunoreactivity. Co-exposure with the peptide CGRP receptor antagonist CGRP8-37, SR140333 or nimesulide prevented the morphine-induced increase in the expression of CGRP immunoreactivity. Additionally, BIBN4096BS, a nonpeptide CGRP receptor antagonist, stereoselectively produced similar effects. In summary, this investigation demonstrates that activity of CGRP and substance P contributes to both the induction and expression of opioid analgesic tolerance. Additionally, it highlights the involvement of prostaglandins generated by spinal cyclooxygenase-2 activity in the genesis of opioid tolerance. The neuropeptide and prostanoid activity contributing to tolerance is expressed at the level of the primary afferents terminating in the spinal cord. The combination of opioids with agents that block this activity may represent a useful strategy for the prevention as well as the reversal of clinical opioid tolerance.

Topics: Animals; Behavior, Animal; Calcitonin Gene-Related Peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Cell Count; Cells, Cultured; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Interactions; Drug Tolerance; Ganglia, Spinal; Immunohistochemistry; Male; Morphine; Morphine Dependence; Neurokinin-1 Receptor Antagonists; Neurons; Pain Measurement; Piperidines; Prostaglandins; Quinuclidines; Rats; Rats, Sprague-Dawley; Receptors, Calcitonin Gene-Related Peptide; Receptors, Neurokinin-1; Spinal Cord; Sulfonamides; Time Factors

In previous studies we found that neuronal overexpression of human cyclooxygenase (COX)-2 in transgenic mice potentiated excitotoxicity in vivo and in vitro. To clarify the molecular mechanisms involved in COX-2-mediated potentiation of excitotoxicity, we used cDNA microarray to identify candidate genes the expression of which is altered in the cerebral cortex of homozygous human hCOX-2 transgenic mice. We found that the mRNA expression of the cell cycle kinase (CDK) inhibitor-inhibitor kinase (INK) p18(INK4), a specific inhibitor of CDK 4,6, which controls the activation of the retinoblastoma (Rb) tumor suppressor protein phosphorylation, was decreased in the brain of adult hCOX-2 homozygous transgenics. Conversely, chronic treatment of the hCOX-2 transgenics with the preferential COX-2 inhibitor nimesulide reversed the hCOX-2-mediated decrease of cortical p18(INK4) mRNA expression in the brain. Further in vitro studies revealed that in primary cortico-hippocampal neurons derived from homozygous hCOX-2 transgenic mice, COX-2 overexpression accelerates glutamate-mediated apoptotic damage that is prevented by the CDK inhibitor flavoperidol. Moreover, treatment of wild-type primary cortico-hippocampal neuron cultures with the COX-2 preferential inhibitor nimesulide significantly attenuated glutamate-mediated apoptotic damage, which coincided with inhibition of glutamate-mediated pRb phosphorylation. These data indicate that hCOX-2 overexpression causes neuronal cell cycle deregulation in the brain and provides further rationale for targeting neuronal COX-2 in neuroprotective therapeutic research.

Topics: Animals; Apoptosis; Cell Cycle; Cell Cycle Proteins; Cerebral Cortex; Cyclin-Dependent Kinase Inhibitor p18; Cyclin-Dependent Kinases; Cyclooxygenase 2; Enzyme Inhibitors; Excitatory Amino Acid Agents; Female; Flavonoids; Glutamic Acid; Isoenzymes; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Phosphorylation; Piperidines; Prostaglandin-Endoperoxide Synthases; Retinoblastoma Protein; RNA, Messenger; Serine; Sulfonamides; Tumor Suppressor Proteins

Piperine is an inhibitor of various hepatic and other enzymes involved in the biotransformation of drugs. Preliminary pharmacokinetic studies conducted by us suggested the increased bioavailability of nimesulide co-administered with piperine. The present study was, thus, conducted to evaluate the antinociceptive, anti-inflammatory and toxicity profile of a new nimesulide-piperine combination administered orally as compared with nimesulide alone. Antinociceptive efficacy was tested using an acetic acid writhing test and tail flick latency test (TFL). The ED50 value of a nimesulide-piperine combination in writhing test was calculated to be significantly lower (1.5 mg kg(-1)) as compared to (11.2 mg kg(-1)) of nimesulide alone. The antinociceptive effect was lesser in the tail flick latency test as compared to what was observed in the writhing test indicating the peripheral action of the Non-Steriodal Anti-Inflammatory Drug (NSAID). In carrageenan-induced inflammatory tests, the nimesulide-piperine combination was found to be dose-to-dose superior than nimesulide alone. Acute toxicity studies on mice revealed a reduction in lethal dose (LD50) of the combination (980 mg kg(-1)) as compared to nimesulide (1500 mg kg(-1)) alone. Results from the present study suggest a better therapeutic index for the nimesulide-piperine combination indicating that this combination would further reduce the frequency of adverse effects associated with nimesulide alone.

Topics: Administration, Oral; Alkaloids; Analgesics, Non-Narcotic; Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzodioxoles; Drug Combinations; Drug Interactions; Female; Inflammation; Lethal Dose 50; Male; Mice; Nociceptors; Piperidines; Polyunsaturated Alkamides; Rats; Rats, Wistar; Sulfonamides