Tonantzitlolone B Modulates the Endogenous Opioid System to Promote Antinociception in Mice.

Tonantzitlolone B (TZL-B) is a diterpene isolated from the roots of Stillingia loranthacea. Its antinociceptive effects were investigated in male Swiss mice using the following models of pain: formalin test, inflammation induced by Complete Freund's Adjuvant (CFA), tail flick test, and cold plate test. The influence of TZL-B on the opioid system was assessed in vivo, using opioid antagonists; in silico, investigating the chemical similarity among TZL-B and opioid agonists; and ex vivo, measuring preproenkephalin (PENK) gene expression in the spinal cord by RT-qPCR. TZL-B (10-1000 µg/kg) promoted antinociception in the four experimental models without impairing mice's motor function. TZL-B did not alter paw edema during CFA-induced inflammation. The antinociceptive effects of TZL-B in the tail flick and cold plate tests were diminished by the opioid antagonists naloxone (5 mg/kg), NOR-BNI (0.5 mg/kg), naltrindole (3 mg/kg), and CTOP (1 mg/kg), indicating the involvement of κ-, δ-, and µ-opioid receptors. TZL-B showed no significant chemical similarity to opioid agonists, but the treatment with TZL-B (1000 µg/kg) increased PENK gene expression in the spinal cord of mice. These data suggest that TZL-B promotes antinociception by enhancing the transcription of PENK, hence modulating the endogenous opioid system.

Unveiling Targets for Treating Postoperative Pain: The Role of the TNF-α/p38 MAPK/NF-κB/Nav1.8 and Nav1.9 Pathways in the Mouse Model of Incisional Pain.

Although the mouse model of incisional pain is broadly used, the mechanisms underlying plantar incision-induced nociception are not fully understood. This work investigates the role of Nav1.8 and Nav1.9 sodium channels in nociceptive sensitization following plantar incision in mice and the signaling pathway modulating these channels. A surgical incision was made in the plantar hind paw of male Swiss mice. Nociceptive thresholds were assessed by von Frey filaments. Gene expression of Nav1.8, Nav1.9, TNF-α, and COX-2 was evaluated by Real-Time PCR in dorsal root ganglia (DRG). Knockdown mice for Nav1.8 and Nav1.9 were produced by antisense oligodeoxynucleotides intrathecal treatments. Local levels of TNF-α and PGE2 were immunoenzymatically determined. Incised mice exhibited hypernociception and upregulated expression of Nav1.8 and Nav1.9 in DRG. Antisense oligodeoxynucleotides reduced hypernociception and downregulated Nav1.8 and Nav1.9. TNF-α and COX-2/PGE2 were upregulated in DRG and plantar skin. Inhibition of TNF-α and COX-2 reduced hypernociception, but only TNF-α inhibition downregulated Nav1.8 and Nav1.9. Antagonizing NF-κB and p38 mitogen-activated protein kinase (MAPK), but not ERK or JNK, reduced both hypernociception and hyperexpression of Nav1.8 and Nav1.9. This study proposes the contribution of the TNF-α/p38/NF-κB/Nav1.8 and Nav1.9 pathways to the pathophysiology of the mouse model of incisional pain.

The Compound (E)-2-Cyano-N,3-diphenylacrylamide (JMPR-01): A Potential Drug for Treatment of Inflammatory Diseases.

The compound (E)-2-cyano-N,3-diphenylacrylamide (JMPR-01) was structurally developed using bioisosteric modifications of a hybrid prototype as formed from fragments of indomethacin and paracetamol. Initially, in vitro assays were performed to determine cell viability (in macrophage cultures), and its ability to modulate the synthesis of nitrite and cytokines (IL-1ß and TNFα) in non-cytotoxic concentrations. In vivo, anti-inflammatory activity was explored using the CFA-induced paw edema and zymosan-induced peritonitis models. To investigate possible molecular targets, molecular docking was performed with the following crystallographic structures: LT-A4-H, PDE4B, COX-2, 5-LOX, and iNOS. As results, we observed a significant reduction in the production of nitrite and IL-1ß at all concentrations used, and also for TNFα with JMPR-01 at 50 and 25 µM. The anti-edematogenic activity of JMPR-01 (100 mg/kg) was significant, reducing edema at 2-6 h, similar to the dexamethasone control. In induced peritonitis, JMPR-01 reduced leukocyte migration by 61.8, 68.5, and 90.5% at respective doses of 5, 10, and 50 mg/kg. In silico, JMPR-01 presented satisfactory coupling; mainly with LT-A4-H, PDE4B, and iNOS. These preliminary results demonstrate the strong potential of JMPR-01 to become a drug for the treatment of inflammatory diseases.

5-O-methylcneorumchromone K Exerts Antinociceptive Effects in Mice via Interaction with GABAA Receptors.

The proper pharmacological control of pain is a continuous challenge for patients and health care providers. Even the most widely used medications for pain treatment are still ineffective or unsafe for some patients, especially for those who suffer from chronic pain. Substances containing the chromone scaffold have shown a variety of biological activities, including analgesic effects. This work presents for the first time the centrally mediated antinociceptive activity of 5-O-methylcneorumchromone K (5-CK). Cold plate and tail flick tests in mice showed that the 5-CK-induced antinociception was dose-dependent, longer-lasting, and more efficacious than that induced by morphine. The 5-CK-induced antinociception was not reversed by the opioid antagonist naloxone. Topological descriptors (fingerprints) were employed to narrow the antagonist selection to further investigate 5-CK's mechanism of action. Next, based on the results of fingerprints analysis, functional antagonist assays were conducted on nociceptive tests. The effect of 5-CK was completely reversed in both cold plate and tail-flick tests by GABAA receptor antagonist bicuculline, but not by atropine or glibenclamide. Molecular docking studies suggest that 5-CK binds to the orthosteric binding site, with a similar binding profile to that observed for bicuculline and GABA. These results evidence that 5-CK has a centrally mediated antinociceptive effect, probably involving the activation of GABAergic pathways.

Physalis angulata concentrated ethanolic extract suppresses nociception and inflammation by modulating cytokines and prostanoids pathways.

Physalins are seco-steroids with a variety of pharmacological activities already described. In this study the pharmacological properties of a standardized concentrated ethanolic extract from Physalis angulata (CEEPA), rich in physalins B, D, F and G, were studied in models of pain and inflammation in mice. Inflammatory mediators were measured by radioimmunoassay and Real-Time PCR in mice paws after the CFA stimuli. Systemic administration of CEEPA produced antinociceptive effect on the writhing test and formalin test. In the writhing test, physalins B, D, F and G showed that the antinociceptive effect of CEEPA is more potent than that of these purified compounds. In addition, CEEPA reduced the levels of TNF-α, IL-1ß, COX-2 and iNOS mRNA in the CFA-induced paw inflammation. Likewise, CEEPA decreased the TNF-α, IL-1ß and PGE2 paw levels. In conclusion, CEEPA induces antinociceptive and anti-inflammatory effects, with improved pharmacological potency relative to pure physalins, associated to modulation of cytokine and cyclooxygenase pathways.

Mesenchymal stem cells reduce the oxaliplatin-induced sensory neuropathy through the reestablishment of redox homeostasis in the spinal cord.

AIMS: The present study was designed to investigate whether the antinociceptive effect of bone marrow-derived mesenchymal stem/stromal cells (MSC) during oxaliplatin (OXL)-induced sensory neuropathy is related to antioxidant properties. MAIN METHODS: Male mice C57BL/6 were submitted to repeated intravenous administration of OXL (1 mg/kg, 9 administrations). After the establishment of sensory neuropathy, mice were treated with a single intravenous administration of MSC (1 × 106), vehicle or gabapentin. Paw mechanical and thermal nociceptive thresholds were evaluated through von Frey filaments and cold plate test, respectively. Motor performance was evaluated in the rota-rod test. Gene expression profile, cytokine levels, and oxidative stress markers in the spinal cord were evaluated by real-time PCR, ELISA and biochemical assays, respectively. KEY FINDINGS: OXL-treated mice presented behavioral signs of sensory neuropathy, such as mechanical allodynia and thermal hyperalgesia, which were completely reverted by a single administration of MSC. Repeated oral treatment with gabapentin (70 mg/kg) induced only transient antinociception. The IL-1ß and TNF-α spinal levels did not differ between mice with or without sensory neuropathy. MSC increased the levels of anti-inflammatory cytokines, IL-10 and TGF-ß, in the spinal cord of neuropathic mice, in addition to increasing the gene expression of antioxidant factors SOD and Nrf-2. Additionally, nitrite and MDA spinal levels were reduced by the MSC treatment. SIGNIFICANCE: MSC induce reversion of sensory neuropathy induced by OXL possibly by activation of anti-inflammatory and antioxidant pathways, leading to reestablishment of redox homeostasis in the spinal cord.

Phenylpropanoids from Croton velutinus with cytotoxic, trypanocidal and anti-inflammatory activities.

This current study presents the phytochemical analysis of Croton velutinus, describing phenylpropanoids obtained from this species. The fractionation of the roots hexane extract led to the isolation of four new phenylpropanoids derivatives, velutines A-D (1-4) and three known (5-7). Their structures were established based on spectroscopic (1D-2D NMR; HRMS and IR) analysis. Cytotoxic, trypanocidal and anti-inflammatory activities of compounds 1-7 were evaluated. Only compounds 2 and 5 showed cytotoxic activity against cancer cell lines (B16F10, HL-60, HCT116, MCF-7 and HepG2), with IC50 values ranging from 6.8 to 18.3 µM and 11.1 to 18.3 µM, respectively. Compounds 2 and 5 also showed trypanocidal activity against bloodstream trypomastigotes with EC50 values of 9.0 and 9.58 µM, respectively. Finally, the anti-inflammatory potential of these compounds was evaluated on cultures of activated macrophages. All compounds exhibited concentration-dependent suppressive activity on the production of nitrite and IL-1ß by macrophages stimulated with LPS and IFN-γ. These results indicate phenylpropanoids esters (2 and 5) from C. velutinus as promising cytotoxic, trypanocidal and anti-inflammatory candidates that warrants further studies.

Antinociceptive compounds and LC-DAD-ESIMSn profile from Dictyoloma vandellianum leaves.

Limonoids, quinolone alkaloids and chromones have been reported as constituents of Dictyoloma vandellianum Adr. Juss. (Rutaceae). Although those compounds are known for their biological activities, only the anti-inflammatory activity of chromones isolated from the underground parts has been evaluated. There are no studies of the pharmacological properties of the aerial parts of D. vandellianum. The present study was carried out to determine the phytochemical profile and antinociceptive activity of the methanol extract, fractions and isolated compounds of leaves of D. vandellianum. The phytochemical profile was performed by HLPC-DAD-ESIMSn and pure substances obtained were characterized by MS and NMR spectroscopy. The antinociceptive activity was assessed using the formalin assay in mice, and the motor function in the rotarod test. ME and all the fractions obtained from ME produced antinociceptive effects. Among them, the ethyl ether fraction was the most active. Data from HPLC-DAD-ESIMSn showed that the ethyl ether fraction presented 42 compounds. The major compounds isolated from this fraction-gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose-were tested and produced antinociceptive effects. Gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose at antinociceptive doses did not affect the motor performance in mice in the rotarod test. This work is the first report of the occurrence of gallotanins in D. vandellianum. In addition, the pharmacological study showed that D. vandellianum leaves present antinociceptive activity, probably induced by gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose.

IGF-1 overexpression improves mesenchymal stem cell survival and promotes neurological recovery after spinal cord injury.

BACKGROUND: Survival and therapeutic actions of bone marrow-derived mesenchymal stem cells (BMMSCs) can be limited by the hostile microenvironment present during acute spinal cord injury (SCI). Here, we investigated whether BMMSCs overexpressing insulin-like growth factor 1 (IGF-1), a cytokine involved in neural development and injury repair, improved the therapeutic effects of BMMSCs in SCI. METHODS: Using a SCI contusion model in C57Bl/6 mice, we transplanted IGF-1 overexpressing or wild-type BMMSCs into the lesion site following SCI and evaluated cell survival, proliferation, immunomodulation, oxidative stress, myelination, and functional outcomes. RESULTS: BMMSC-IGF1 transplantation was associated with increased cell survival and recruitment of endogenous neural progenitor cells compared to BMMSC- or saline-treated controls. Modulation of gene expression of pro- and anti-inflammatory mediators was observed after BMMSC-IGF1 and compared to saline- and BMMSC-treated mice. Treatment with BMMSC-IGF1 restored spinal cord redox homeostasis by upregulating antioxidant defense genes. BMMSC-IGF1 protected against SCI-induced myelin loss, showing more compact myelin 28 days after SCI. Functional analyses demonstrated significant gains in BMS score and gait analysis in BMMSC-IGF1, compared to BMMSC or saline treatment. CONCLUSIONS: Overexpression of IGF-1 in BMMSC resulted in increased cell survival, immunomodulation, myelination, and functional improvements, suggesting that IGF-1 facilitates the regenerative actions of BMMSC in acute SCI.

Natural chromones as potential anti-inflammatory agents: Pharmacological properties and related mechanisms.

Chromones are a group of natural substances with a diversity of biological activities. Herein we assessed the pharmacological potential of three chromones (1, 2 and 3) isolated from Dictyoloma vandellianum as anti-inflammatory agents using in vitro and in vivo approaches. During in vitro screening, the production of NO and cytokines by macrophages stimulated with LPS and IFN-γ was inhibited by all chromones at concentrations (5-20 µM) that did not induce cytotoxicity. Analysis of pharmacokinetic parameters (in vitro half-life and intrinsic clearance) using human liver microsomes revealed that 3 has a superior pharmacokinetic profile, compared to 1 and 2. Treatment with 3 (100 mg/kg, ip) did not affect the mice motor performance, while 1 and 2 induced motor deficit. Taking into account the pharmacokinetic profile and absence of motor impairment, 3 was selected for further pharmacological characterization. Corroborating the data from in vitro screening, treatment of cell cultures with 3 (5-20 µM) reduced TNF-α, IL-6 and IL-1ß production by stimulated macrophages. In the complete Freund's adjuvant-induced paw inflammation model in mice, 3 (25 and 50 mg/kg, ip) inhibited mechanical hyperalgesia, edema and cytokine production/release (IL-1ß, IL-6 and TNF-α). 3 (5-20 µM) also reduced the transcriptional activity of NF-κB in stimulated macrophages. Furthermore, treatment with RU486, a glucocorticoid receptor (GR) antagonist, partially prevented the inhibitory effect of 3 on macrophages, indicating that this chromone exerts its anti-inflammatory effects in part through the activation of GR. The results presented herein demonstrate the pharmacological potential of natural chromones, highlighting 3 as a possible candidate for the drug discovery process targeting new anti-inflammatory drugs.

Fluorescent Canthin-6-one Alkaloids from Simaba bahiensis: Isolation, Identification, and Cell-Labeling Properties.

Canthin-6-one alkaloids, which are present in plants of the genus Simaba, are natural compounds that are capable of acting as fluorescent probes. However, the chemical composition and fluorescent properties of most species of this genus have not been analyzed. The objective of this study was to characterize the fluorescent properties of an extract of S. bahiensis and identify the chemical entities responsible for these properties. In addition, the cell-labeling properties of the fluorescent dye from A and of the isolated compounds were characterized by confocal fluorescence microscopy and flow cytometry. One quassinoid and three fluorescent alkaloids were isolated from S. bahiensis, all compounds were identified by using NMR spectroscopy and high-resolution mass spectrometry. Staining experiments and HPLC-FL analysis shown that canthin-6-one alkaloids are the main green fluorescent compounds in the analyzed dyes. All compounds evaluated showed a cytoplasmic marker with a residence time of 24 h. The present study is the first to describe the presence of canthin-6-one alkaloids in S. bahiensis, in addition to demonstrating promising cell-labeling properties of fluorescent compounds from S. bahiensis with broad emission wavelengths.

Pain-like behaviors and local mechanisms involved in the nociception experimentally induced by Latrodectus curacaviensis spider venom.

The present study was undertaken to characterize the behavioral manifestations of nociception and the local mechanisms involved with the nociceptive response elicited by Latrodectus curacaviensis venom (LCV) in mice. After the intraplantar LCV inoculation, spontaneous nociception, mechanical and thermal nociceptive thresholds, motor performance, edema and cytokine levels were evaluated using von Frey filaments, hot/cold plate, rota-rod, plethismometer and ELISA, respectively. Analysis of LCV was performed by SDS-PAGE and chromatography. Intraplantar injection of LCV (1-100 ng/paw) induced intense and heat-sensitive spontaneous nociception, mediated by serotonin and bradykinin receptors, TRPV1 channels, as well as by transient local inflammation. LCV (0.1-10 ng/paw) induced mechanical allodynia, which was reduced by the local pretreatment with H1 receptor or TRPV1 antagonists. Corroborating the TRPV1 involvement, in thermal nociception assays, LCV induced a similar response to that of capsaicin, a TRPV1 agonist, facilitating the response to noxious hot stimuli and inhibiting the response to cold noxious stimulation. LCV promoted mast cell degranulation, increased IL-1ß paw levels, but did not produce a relevant edematogenic effect. Analysis of LCV components showed a predominance of high molecular weight proteins. This work provides the first mechanistic hypothesis to explain the local pain induced by LCV, the most frequent clinical symptom of human envenomation.

Betulinic acid derivative BA5, a dual NF-kB/calcineurin inhibitor, alleviates experimental shock and delayed hypersensitivity.

Betulinic acid (BA) is a naturally occurring triterpenoid with several biological properties already described, including immunomodulatory activity. Here we investigated the immunomodulatory activity of eight semi-synthetic amide derivatives of betulinic acid. Screening of derivatives BA1-BA8 led to the identification of compounds with superior immunomodulatory activity than BA on activated macrophages and lymphocytes. BA5, the most potent derivative, inhibited nitric oxide and TNFα production in a concentration-dependent manner, and decreased NF-κB activation in Raw 264.7 cells. Additionally, BA5 inhibited the proliferation of activated lymphocytes and the secretion of IL-2, IL-4 IL-6, IL-10, IL-17A and IFNÉ£, in a concentration-dependent manner. Flow cytometry analysis in lymphocyte cultures showed that treatment with BA5 induces cell cycle arrest in pre-G1 phase followed by cell death by apoptosis. Moreover, BA5 also inhibited the activity of calcineurin, an enzyme that plays a critical role in the progression of cell cycle and T lymphocyte activation. BA5 has a synergistic inhibitory effect with dexamethasone on lymphoproliferation, showing a promising profile for drug combination. Finally, we observed immunosuppressive effects of BA5 in vivo in mouse models of lethal endotoxemia and delayed type hypersensitivity. Our results reinforce the potential use of betulinic acid and its derivatives in the search for potent immunomodulatory drugs.

The anti-inflammatory and immunomodulatory potential of braylin: Pharmacological properties and mechanisms by in silico, in vitro and in vivo approaches.

Braylin belongs to the group of natural coumarins, a group of compounds with a wide range of pharmacological properties. Here we characterized the pharmacological properties of braylin in vitro, in silico and in vivo in models of inflammatory/immune responses. In in vitro assays, braylin exhibited concentration-dependent suppressive activity on activated macrophages. Braylin (10-40 µM) reduced the production of nitrite, IL-1ß, TNF-α and IL-6 by J774 cells or peritoneal exudate macrophages stimulated with LPS and IFN-γ. Molecular docking calculations suggested that braylin present an interaction pose to act as a glucocorticoid receptor ligand. Corroborating this idea, the inhibitory effect of braylin on macrophages was prevented by RU486, a glucocorticoid receptor antagonist. Furthermore, treatment with braylin strongly reduced the NF-κB-dependent transcriptional activity on RAW 264.7 cells. Using the complete Freund's adjuvant (CFA)-induced paw inflammation model in mice, the pharmacological properties of braylin were demonstrated in vivo. Braylin (12.5-100 mg/kg) produced dose-related antinociceptive and antiedematogenic effects on CFA model. Braylin did not produce antinociception on the tail flick and hot plate tests in mice, suggesting that braylin-induced antinociception is not a centrally-mediated action. Braylin exhibited immunomodulatory properties on the CFA model, inhibiting the production of pro-inflammatory cytokines IL-1ß, TNF-α and IL-6, while increased the anti-inflammatory cytokine TGF-ß. Our results show, for the first time, anti-inflammatory, antinociceptive and immunomodulatory effects of braylin, which possibly act through the glucocorticoid receptor activation and by inhibition of the transcriptional activity of NF-κB. Because braylin is a phosphodiesterase-4 inhibitor, this coumarin could represent an ideal prototype of glucocorticoid receptor ligand, able to induce synergic immunomodulatory effects.

Nanomolar anti-sickling compounds identified by ligand-based pharmacophore approach.

Adenosine receptors are considered as potential targets for drug development against several diseases. The discovery of subtype 2B adenosine receptors role in erythrocyte sickling process proved its importance to neglected diseases such as sickle cell anemia, which affects approximately 29.000 people around the world, but whose treatment is restricted to just one FDA approved drug (hydroxyurea). In order to widen the therapeutic arsenal available to treat sickle cell anemia patients, it is imperative to identify new lead compounds that modify the sickling course and not just its symptoms. In order to accomplish this goal, ligand-based pharmacophore models that differentiate true ligands from decoys and enlighten the structure-activity relationship of known RA2B antagonists were employed screen the lead-like subset of the ZINC database. Following a chemical diversity analysis, 18 compounds were selected for biological evaluation. Among them, one molecule Z1139491704 (pEC50 = 7.77 ± 0.17) has shown better anti-sickling activity than MRS1754 (pEC50 = 7.63 ± 0.12), a commercial RA2B antagonist. Moreover, these compounds exhibited no cytotoxic effect at low micromolar range on mammalian cells. In conclusion, the sound development of validated ligand-based pharmacophore models proved essential to identify novel chemical scaffolds that might be useful to develop anti-sickling drugs.

Structural improvement of new thiazolidinones compounds with antinociceptive activity in experimental chemotherapy-induced painful neuropathy.

Chemotherapy-induced neuropathy is a disabling pain condition resulting from chemotherapy for cancers. Up to now, no drug is available to cure chemotherapy-induced neuropathy. In the present study, we describe the structural design, synthesis, chemical and pharmacological characterization of 15 thiazolidinones, a class of potential analgesic compounds. The synthesis of new thiazolidinones was achieved by using the thiazolidinone heterocyclic as main structural pharmacophoric group and varying the substituents attached to the phenyl near to the iminic bond. The analgesic potential of the compounds was investigated in a mice model of oxaliplatin-induced neuropathic pain, using von Frey, rota-rod and open-field tests. Except for compound 14, these thiazolidinones exhibited antinociceptive property without causing motor impairment. Thiazolidinones 12, 15 and 16 displayed a dose-dependent antinociceptive effect, with similar efficacy and enhanced potency than gabapentin, the gold standard drug used for neuropathic pain. In addition, the antinociceptive activity of 16 lasted longer than gabapentin. The antinociceptive effect of thiazolidinones was prevented by GW9662, a PPARγ antagonist. The main antinociceptive compounds exhibited positive Lipinski's index, predicting their oral bioavailability. In conclusion, the structural design performed here led to the identification of new compounds endowed with potent antinociceptive activity, potentially useful to treat chemotherapy-induced neuropathic pain.

Pharmacological Properties of Riparin IV in Models of Pain and Inflammation.

Riparins, natural alkaloids of the alkamide group, can be synthesized by simple methods, enhancing their potential application in pharmaceutical development. Here, the pharmacological properties of riparins were investigated in in vitro and in vivo assays of pain and inflammation in Swiss mice. Inflammatory mediators were measured by radioimmunoassay and Real-Time PCR. Riparins I, II, III and IV (1.56-100 mg/kg; ip) produced dose-related antinociceptive effects in the formalin test, exhibiting ED50 values of 22.93, 114.2, 31.05 and 6.63 mg/kg, respectively. Taking the greater potency as steering parameter, riparin IV was further investigated. Riparin IV did not produce antinociceptive effect on the tail flick, suggesting that its antinociception is not a centrally-mediated action. In fact, riparin IV (1.56-25 mg/kg) produced dose-related antinociceptive and antiedematogenic effects on the complete Freund's adjuvant (CFA)-induced paw inflammation in mice. During CFA-induced inflammation, riparin IV did not modulate either the production of cytokines, TNF-α and IL-10, or COX-2 mRNA expression. On the other hand, riparin IV decreased the PGE2 levels in the inflamed paw. In in vitro assays, riparin IV did not exhibit suppressive activities in activated macrophages. These results indicate, for the first time, that riparin IV induces antinociceptive and anti-inflammatory effects, possibly through the inhibition of prostanoid production.

Bisphosphonates: Pharmacokinetics, bioavailability, mechanisms of action, clinical applications in children, and effects on tooth development.

Bisphosphonates (BPs) avidly bind to calcium crystals and inhibit osteoclastic bone resorption, making them useful for treatment of skeletal disorders such as osteoporosis, Paget's disease, osteogenesis imperfecta and metastatic bone diseases. BPs therapeutically act by causing toxic effects on osteoclasts or interfering with specific intracellular pathways in those cells. BPs that possess nitrogen in their composition are called nitrogen-containing BPs (NBPs) and include alendronate, pamidronate, risedronate, ibandronate, and zoledronate. Simple BPs or non-NBPs do not have nitrogen in their composition, include etiodronate and clodronate, and were the first to be tested in animals and clinically used. Because BPs may be administered to pregnant women or children during deciduous and permanent teeth development, it is expected that they might disturb tooth eruption and development. A review of current literature on pharmacokinetics, bioavailability, mechanisms of action, and clinical applications of BPs in children, and their effects on tooth eruption and development is presented.