Interaction of morphine with a new alpha2-adrenoceptor agonist in mice

Antidepressant effect of PT-31, an α₂-adrenoceptor agonist, on lipopolysaccharide-induced depressive-like behavior in mice

Increasing evidence indicates that neuroinflammation, oxidative stress, and neurotrophic factors play a key role in the pathophysiology of major depressive disorder (MDD). In addition, the attenuation of inflammatory response has been considered a putative mechanism for MDD treatment. PT-31 is an imidazolidine derivative and a putative α₂-adrenoceptor agonist that has previously demonstrated antinociceptive activity. The present study aimed to investigate the effect of PT-31 on depressive-like behavior and lipopolysaccharide-induced neurochemical changes. To this end, mice received intraperitoneally saline or lipopolysaccharide (600 µg/kg), and 5 h postinjection animals were orally treated with saline, PT-31 (3, 10, and 30 mg/kg), or fluoxetine (30 mg/kg). Mice were subjected to the open field test (OFT) 6 and 24 h after lipopolysaccharide administration and to the tail suspension test (TST) 24 h postlipopolysaccharide. Subsequently, animals were euthanized, and brains were dissected for neurochemical analyses. The administration of lipopolysaccharide-induced sickness- and depressive-like behaviors, besides promoting an increase in myeloperoxidase activity and a reduction in brain-derived neurotrophic factor (BDNF) levels. Noteworthy, PT-31 3 mg/kg attenuated lipopolysaccharide-induced decreased locomotor activity 6 h after lipopolysaccharide in the OFT. All tested doses of PT-31 significantly reduced the immobility time of animals in the TST and attenuated lipopolysaccharide-induced increased myeloperoxidase activity in the cortex of mice. Our results demonstrate that PT-31 ameliorates behavioral changes promoted by lipopolysaccharide in OFT and TST, which is possibly mediated by attenuation of the inflammatory response.

Therapeutic Applications of Self-assembled Indole-3-butanoyl-polyethylenimine Nanostructures

This study demonstrates the therapeutic potential of indole-3-butanoyl-polyethylenimine (IBP) nanostructures formed via self-assembly in aqueous system. Dynamic light scattering (DLS) analysis confirmed the formation of the nanostructures in the size range of ~ 194-331 nm. These nanostructures showed commendable antimicrobial activity against wide range of microbes including multi-drug resistant bacteria. Besides, appreciable antioxidant and anti-inflammatory activities were also observed. Results of cytotoxicity studies, performed on normal transformed human embryonic kidney (HEK 293) cells and human red blood cells (hRBCs), revealed almost non-toxic behavior of these nanostructures, however, remarkable toxicity on human breast cancer cells (MCF-7), human osteosarcoma cells (Mg63) and human liver cancer cells (HepG2) was observed. The pre-apoptotic and anti-proliferative activity of IBP nanostructures were confirmed by acridine orange/propidium iodide dual staining assay followed by confocal microscopy and scratch assay on Mg63 cells. Taken together, these results advocate the promising potential of the synthesized IBP nanostructures in the therapeutic applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-022-01015-y.

Study of the acute and repeated dose 28-day oral toxicity in mice treated with PT-31, a molecule with potential antipsychotic profile

Schizophrenia is a psychiatric disorder that affects 1% of the world population and is treated with antipsychotics, which may induce important biochemical and hematological alterations. Since it is necessary to verify the safety of new molecules with antipsychotic potential, the present study aimed to evaluate the oral toxicity of PT-31, a putative α₂-adrenoreceptor agonist, after acute (2000 mg/kg) and repeated doses (28 days) gavage treatment, in three different doses: minimum effective dose in animal models (10 mg/kg), twice the dose (20 mg/kg), and four times the dose (40 mg/kg), as recommended by the OECD guidelines. Balb/C female adult mice were used, and biochemical, hematological, and histopathological analyses were performed. PT-31 10 and 20 mg/kg did not cause biochemical alterations related to hepatic and renal toxicity, and neither altered glycemic and lipid profiles. The preclinical dose of PT-31 also did not promote mice histopathological changes in the liver, kidney, and brain. In the hematimetric parameters, PT-31 only increased HGB at 20 mg/kg, and MCH and MCHC at 40 mg/kg. However, all the tested doses of PT-31 showed platelet increase, which must be better investigated. Therefore, further studies are needed to investigate the safety of PT-31 as a potential antipsychotic drug.

Thiazolidine derivatives: In vitro toxicity assessment against promastigote and amastigote forms of Leishmania infantum and ultrastructural study

Neglected diseases, such as Leishmaniasis, constitute a group of communicable diseases that occur mainly in tropical countries. Considered a public health problem with limited treatment. Therefore, there is a need for new therapies. In this sense, our proposal was to evaluate in vitro two series of thiazolidine compounds (7a-7e and 8a-8e) against Leishmania infantum. We performed in vitro evaluations through macrophage cytotoxicity assays (J774) and nitric oxide production, activity against promastigotes and amastigotes, as well as ultrastructural analyzes in promastigotes. In the evaluation of cytotoxicity, the thiazolidine compounds presented CC₅₀ values between 8.52 and 126.83 μM. Regarding the evaluation against the promastigote forms, the IC₅₀ values ranged between 0.42 and 142.43 μM. Compound 7a was the most promising, as it had the lowest IC₅₀. The parasites treated with compound 7a showed several changes, such as cell body shrinkage, shortening and loss of the flagellum, intense mitochondrial edema and cytoplasmic vacuolization, leading the parasite to cell inviability. In assays against the amastigote forms, the compound showed a low IC₅₀ (0.65 μM). These results indicate that compound 7a was efficient for both evolutionary forms of the parasite. In silico studies suggest that the compound has good oral bioavailability. These results show that compound 7a is a potential drug candidate for the treatment of Leishmaniasis.

Study of the in vitro metabolic profile of a new α2-adrenergic agonist in rat and human liver microsomes by using liquid chromatography-multiple-stage mass spectrometry and nuclear magnetic resonance

A potent synthetic α₂-adrenergic agonist called PT-31, (3-(2-chloro-6-fluorobenzyl)-imidazolidine-2,4-dione), was recently detected as a potential drug to be used as an adjuvant drug to treat chronic pain. The excellent pharmacological property of PT-31 highlights the importance in elucidating its metabolism, which could provide valuable information about its metabolite profile for further pharmacokinetics studies and additionally to estimate the impact of its metabolites on the efficacy, safety and elimination of PT-31. In this work, the study of the in vitro metabolism of PT-31 was initially carried out by using a liquid chromatography coupled to ion trap multiple-stage mass spectrometer (LC-IT-MSⁿ) and a hybrid triple quadrupole/linear ion trap mass spectrometer (LC-QTrap). The production of at least three unknown oxidative metabolites was observed. Structural identification of the unknown metabolites was carried out by combination of LC-MS experiments, including selected reaction monitoring (SRM) and multi-stage full scan experiments. Further analysis of ¹H-NMR led to the structural confirmation of the major metabolite. The results indicated that PT-31 was metabolized by a hydroxylation reaction in the imidazolidine-2,4-dione ring in rat and human liver microsomes, producing the metabolite 3-(2-chloro-6-fluorobenzyl)-5-hydroxyimidazolidine-2,4-dione in rat liver microsomes. A carbon hydroxylation onto the benzyl ring, produced two other minor metabolites of the PT-31 in rat liver microsomes.

Comparison of dexmedetomidine vs. remifentanil combined with sevoflurane during radiofrequency ablation of hepatocellular carcinoma: a randomized controlled trial

BACKGROUND

Remifentanil is widely used for ultrasound-guided percutaneous radiofrequency ablation (RFA) of small hepatocellular carcinoma (HCC). We determined whether dexmedetomidine could be an alternative to remifentanil for RFA of HCC under general anesthesia with sevoflurane.

METHODS

We prospectively randomized patients scheduled to undergo RFA for HCC to a dexmedetomidine (DEX) group or remifentanil (REMI) group (47 patients each). In the DEX group, a bolus infusion (0.4 μg kg^- 1) was started 15 min before anesthesia induction and continued at 0.2 μg kg^- 1 h^- 1 until 10 min before the end of surgery. In the REMI group, 3 μg kg^- 1 h^- 1 of remifentanil was administered from 15 min before anesthesia induction to the end of the surgery. The primary endpoint was postoperative pain intensity. Secondary endpoints included analgesic requirement, postoperative liver function, patient comfort, and hemodynamic changes. Group allocation was concealed from patients and data analysts but not from anesthesiologists.

RESULTS

Postoperative pain intensity, analgesic consumption, comfort, liver function, and time to emergence and extubation did not differ between the two groups. Heart rate, but not mean arterial pressure, was significantly lower in the DEX group than in the REMI group, at 1 min after intubation and from 30 min after the start of the surgery until anesthesia recovery. Sevoflurane concentration and dosage were significantly lower in the DEX group than in the REMI group.

CONCLUSION

During RFA for HCC, low-dose dexmedetomidine reduced the heart rate and need for inhalational anesthetics, without exacerbating postoperative discomfort or liver dysfunction. Although it did not exhibit outstanding advantages over remifentanil in terms of pain management, dexmedetomidine could be a safe alternative adjuvant for RFA under sevoflurane anesthesia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-OPC-15006613 . Registered on 16 June 2015.

Novel agonist of α4β2* neuronal nicotinic receptor with antinociceptive efficacy in rodent models of acute and chronic pain

Objective

To demonstrate the antinociceptive and antihypersensitivity mechanisms of Cris-104 (1-{2-[5-(4-fluorophenyl)-1H-pyrazol-4-yl]ethyl}piperidine), a novel selective α₄β₂* nicotinic acetylcholine receptor (nAChR) agonist, in rodent acute/inflammatory and chronic pain models.

Materials and methods

Hot-plate and formalin tests in mice were used to examine Cris-104-induced antinociceptive effects on thermal/inflammatory pain. Cris-104 effects on hypersensitivity, norepinephrine (NE) release in the spinal dorsal horn, and neuronal activity in the locus coeruleus (LC) were examined in rats with lumbar spinal nerve ligation using behavioral, microdialysis, and extracellular recording methods. Cris-104 effects on spontaneous locomotion were examined in an open-field test.

Results

Cris-104 induced dose-dependent antinociception effects in hot-plate and formalin tests, and these effects were blocked by the general nAChR antagonist mecamylamine, the selective α₄β₂* nAChR antagonist dihydro-beta-erythroidine, and the α₂-adrenoceptor antagonist yohimbine, but not by the α₁-adrenoceptor antagonist prazosin. Systemic and spinally perfused Cris-104 increased NE concentrations in microdialysates from the spinal cord in both normal and SNL rats. Systemic Cris-104 increased neuronal activity in the LC of normal rats. Mecamylamine blocked the effects of Cris-104 on spinal NE release and LC neuronal activity. Systemic Cris-104 did not affect locomotor activity significantly.

Conclusion

The α₄β₂ neuronal nAChR agonist, Cris-104, was effective for treatment of pain via descending noradrenergic inhibition of pain signaling.

Tetrabenazine, a vesicular monoamine transporter-2 inhibitor, attenuates morphine-induced hyperlocomotion in mice through alteration of dopamine and 5-hydroxytryptamine turnover in the cerebral cortex

A single administration with morphine (30 mg/kg, i.p.) induced long-lasting hyperlocomotion in male ICR mice. Pretreatment of mice with a benzoquinolizine derivative tetrabenazine (TBZ; a reversible vesicular monoamine transporter-2 inhibitor) (1 mg/kg, i.p.) for 30 min significantly attenuated the hyperlocomotion induced by morphine, as compared with vehicle (saline)-pretreated mice. No significant change in locomotion was observed in mice pretreated with TBZ (1 mg/kg) alone. Mice treated with TBZ (1 mg/kg) showed an increase in immobility time in a tail suspension test, as compared with saline-treated mice. Pretreatment with TBZ (1 mg/kg) had no effect on morphine (1-30 mg/kg)-induced antinociception. TBZ at a dose of 1 mg/kg inhibited dopamine turnover (the ratio of 3,4-dihydroxyphenylacetic acid/dopamine) and 5-hydroxytryptamine turnover (the ratio of 5-hydroxyindoleacetic acid/5-hydroxytryptamine) in the cerebral cortex of mice challenged with morphine, as compared with saline-pretreated mice challenged with morphine. No stereotypic behavior was observed in mice treated with morphine (30 mg/kg) in combination with TBZ (1 mg/kg), so the reduction in observed locomotion did not result from induction of stereotypical behavior. Moreover, TBZ (1 and 2 mg/kg) pretreatment had no effect on stereotyped behaviors observed in mice challenged with 10 mg/kg methamphetamine. These data support the potential antagonistic actions of TBZ on some opiate actions, and encourage further exploration of potential effects on morphine reinforcement.

Synergistic interaction between a PDE5 inhibitor (sildenafil) and a new adenosine A2A receptor agonist (LASSBio-1359) improves pulmonary hypertension in rats

Introduction

Pulmonary hypertension (PH) is characterized by enhanced pulmonary vascular resistance, which causes right ventricle (RV) pressure overload and results in right sided heart failure and death. This work investigated the effectiveness of a combined therapy with PDE5 inhibitor (PDE5i) and a new adenosine A2A receptor (A2AR) agonist in mitigating monocrotaline (MCT) induced PH in rats.

Methods

An in vitro isobolographic analysis was performed to identify possible synergistic relaxation effect between sildenafil and LASSBio 1359 in rat pulmonary arteries (PAs). In the in vivo experiments, PH was induced in male Wistar rats by a single intraperitoneal injection of 60 mg/kg MCT. Rats were divided into the following groups: control (saline injection only), MCT + vehicle, MCT + sildenafil, MCT + LASSBio 1359 and MCT + combination of sildenafil and LASSBio 1359. Fourteen days after the MCT injection, rats were treated daily with oral administration of the regimen therapies or vehicle for 14 days. Cardiopulmonary system function and structure were evaluated by echocardiography. RV systolic pressure and PA endothelial function were measured.

Results

Isobolographic analysis showed a synergistic interaction between sildenafil and LASSBio 1359 in rat PAs. Combined therapy with sildenafil and LASSBio 1359 but not monotreatment with low dosages of either sildenafil or LASSBio 1359 ameliorated all of PH related abnormalities in cardiopulmonary function and structure in MCT challenged rats.

Conclusions

The combination of sildenafil and LASSBio 1359 has a synergistic interaction, suggesting that combined use of these pharmacological targets may be an alternative to improve quality of life and outcomes for PH patients.

Antinociception induced by a novel α2A adrenergic receptor agonist in rodents acute and chronic pain models

The mechanisms and antinociceptive effects of a novel α_2A adrenoceptor agonist, 3-(2-chloro-6-fluorobenzil)-imidazolinide-2,4-dione (PT-31) were investigated using animal models of acute and chronic pain. The effects of PT-31 on pain responses were examined using hot plate and formalin tests in mice and spinal nerve ligation (SNL)-induced hyperalgesia in rats. The effects of antagonists acting on α adrenoceptor were assessed to investigate the interaction of these pathways upon PT-31 induced antinociception. PT-31 effects on motor activity/skills and on hemodynamic parameters were also evaluated. PT-31 had dose-dependent antinociception effects on hot-plate and formalin-injection induced pain responses. Thermal hyperalgesia and mechanical allodynia were reduced following a 7 d treatment with PT-31 (1, 5, and 10mg/kg/d, p.o.), and those effects were attenuated by yohimbine (5mg/kg), atropine (2mg/kg), L-nitro arginine methyl ester (L-NAME; 30mg/kg), or naloxone (2mg/kg). In contrast to clonidine, PT-31 did not have locomotor or hemodynamic effects in rats. The present results suggest that PT-31 represents a candidate for pain treatment with advantages over clonidine, namely no locomotor or hemodynamic impairments.

Synthesis and biological evaluation of novel imidazolidine derivatives as candidates to schistosomicidal agents

INTRODUCTION:

Schistosomiasis is an infectious parasitic disease caused by trematodes of the genus Schistosoma, which threatens at least 258 million people worldwide and its control is dependent on a single drug, praziquantel. The aim of this study was to evaluate the anti-Schistosoma mansoni activity in vitro of novel imidazolidine derivatives.

MATERIAL AND METHODS:

We synthesized two novel imidazolidine derivatives: (LPSF/PTS10) (Z)-1-(2-chloro-6-fluorobenzyl)-4-(4-dimethylaminobenzylidene)-5-thioxoimidazolidin-2-one and (LPSF/PTS23) (Z)-1-(2-chloro-6-fluoro-benzyl)-5-thioxo-4-(2,4,6-trimethoxy-benzylidene)-imidazolidin-2-one. The structures of two compounds were determined by spectroscopic methods. During the biological assays, parameters such as motility, oviposition, mortality and analysis by Scanning Electron Microscopy were performed.

RESULTS:

LPSF/PTS10 and LPSF/PTS23 were considered to be active in the separation of coupled pairs, mortality and to decrease the motor activity. In addition, LPSF/PTS23 induced ultrastructural alterations in worms, after 24 h of contact, causing extensive erosion over the entire body of the worms.

CONCLUSION:

The imidazolidine derivatives containing the trimetoxy and benzylidene halogens showed promising in vitro schistosomicidal activity.

Antinociceptive effects of hydroalcoholic extract from Euterpe oleracea Mart. (Açaí) in a rodent model of acute and neuropathic pain

Background

Plants rich in flavonoids, such as açaí (Euterpe oleraceae Mart.), can induce antinociception in experimental animals. Here, we tested an extract obtained from the stones of açaí fruits (açaí stone extract, ASE), a native plant from the Amazon region of Brazil, in models of acute/inflammatory and chronic pain.

Methods

Antinociceptive effects of ASE were evaluated in the hot plate, formalin, acetic acid writhing, carrageenan, and neuropathic pain models, as well as in thermal hyperalgesia and mechanical allodynia models induced by spinal nerve ligation. Antinociceptive activities were modulated by the administration of cholinergic, adrenergic, opioid, and L-arginine-NO antagonists.

Results

Oral administration of ASE (30, 100, or 300 mg.kg⁻¹) dose-dependently reduced nociceptive responses to acute/inflammatory pain in mice, including thermal hyperalgesia, acetic acid-induced writhing, and carrageenan-induced thermal hyperalgesia. Moreover, ASE reduced the neurogenic and inflammatory phases after intraplantar injection of formalin in mice. The antinociceptive effect of ASE (100 mg · kg⁻¹) in a hot plate protocol, was inhibited by pre-treatment with naloxone (1 mg · kg⁻¹), atropine (2 mg · kg⁻¹), yohimbine (5 mg · kg⁻¹), or L-NAME (30 mg · kg⁻¹). Furthermore, ASE prevented chronic pain in a rat spinal nerve ligation model, including thermal hyperalgesia and mechanical allodynia.

Conclusion

ASE showed significant antinociceptive effect via a multifactorial mechanism of action, indicating that the extract may be useful in the development of new analgesic drugs.

Antinociceptive effect of hydantoin 3-phenyl-5-(4-ethylphenyl)-imidazolidine-2,4-dione in mice

Imidazolidine derivatives, or hydantoins, are synthetic compounds with different therapeutic applications. Many imidazolidine derivatives have psychopharmacological properties, such as phenytoin, famous for its anticonvulsant efficacy, but also effective in the treatment of neuropathic pain. The hydantoin, 3-phenyl-5-(4-ethylphenyl)-imidazolidine-2,4-dione (IM-3), synthesized from the amino acid, glycine, was selected for psychopharmacological studies in mice on the basis of its chemical and structural similarity with phenytoin. The first step of this study was to define the LD₅₀, which determined the doses of 50, 100 and 200 mg/kg for subsequent tests. The results obtained from the behavioral screening indicated that IM-3 produces decreased ambulation and analgesia in mice. Motor coordination and anxiety behavior were not affected by treatment with IM-3, as observed in the rotarod and elevated plus-maze tests, respectively. Regarding its antinociceptive properties, IM-3 showed efficacy in the acetic acid-induced writhing test by increasing the latency of the first writhe and reducing the number of writhes, as well as reducing the paw licking time in the second phase of the formalin test. The behavior of treated animals exposed to the hot plate test, however, did not differ from that of the control group. These data suggest that IM-3 has antinociceptive effects in mice, which is probably mediated by anti-inflammatory mechanisms.

Uliginosin B, a natural phloroglucinol derivative, presents a multimediated antinociceptive effect in mice

Objective

Investigate the involvement of monoaminergic and glutamatergic systems on the antinociceptive and ataxic effects of uliginosin B, which we have already demonstrated to be a promising molecular scaffold to develop new analgesic drugs.

Methods

Uliginosin B was obtained from hexane extract of aerial parts of Hypericum polyanthemum by chromatographic methods. Uliginosin B antinociceptive and motor coordination effects were evaluated in mice by using hot-plate (15 and 90 mg/kg, i.p.) and rotarod (90 mg/kg, i.p.) tests, respectively. The mechanism of action was investigated through pretreatments with prazosin 1 mg/kg intraperitoneal (α1 receptor antagonist), yohimbine 5 mg/kg intraperitoneal (α2 receptor antagonist), pCPA 300 mg/kg intraperitoneal (serotonin synthesis inhibitor) and MK-801 0.25 mg/kg intraperitoneal (N-methyl-D-aspartic acid receptor antagonist).

Key findings

The antinociceptive effect of uliginosin B (15 and 90 mg/kg, i.p.) was reduced significantly by pCPA and MK-801. Prazosin and yohimbine improved the antinociceptive effect of the highest dose (90 mg/kg, i.p.) of uliginosin B only. The ataxic effect of uliginosin B (90 mg/kg, i.p.) was completely prevented by pretreatment with pCPA or MK-801, but it was unaffected by pretreatment with prazosin or yohimbine.

Conclusion

These data confirm the contribution of monoaminergic neurotransmission as well as provide the first evidence of glutamatergic neurotransmission contribution to the uliginosin B effects.

The effects of intra-operative dexmedetomidine on postoperative pain, side-effects and recovery in colorectal surgery

In this double-blind, randomised study, 100 patients undergoing open or conventional laparoscopic colorectal surgery received an intra-operative loading dose of dexmedetomidine 1 μg.kg(-1) followed by an infusion of 0.5 μg.kg(-1) .h(-1) , or a bolus and infusion of saline 0.9% of equivalent volume. Forty-six patients in the dexmedetomidine group and 50 in the saline group completed the study. The area under the curve of numerical rating scores for pain at rest for 1-48 h postoperatively was significantly lower in the patients receiving dexmedetomidine (p = 0.041). There was no difference in morphine consumption, duration of recovery ward or hospital stay. From the data obtained in this study, we calculated a number needed to treat for effective pain relief of 4. Intra-operative dexmedetomidine in colorectal surgery resulted in a reduction in resting pain scores, but there was no morphine-sparing effect or improvement in patients' recovery outcome measures.

Mechanisms of acupuncture-electroacupuncture on persistent pain

In the last decade, preclinical investigations of electroacupuncture mechanisms on persistent tissue injury (inflammatory), nerve injury (neuropathic), cancer, and visceral pain have increased. These studies show that electroacupuncture activates the nervous system differently in health than in pain conditions, alleviates both sensory and affective inflammatory pain, and inhibits inflammatory and neuropathic pain more effectively at 2 to 10 Hz than at 100 Hz. Electroacupuncture blocks pain by activating a variety of bioactive chemicals through peripheral, spinal, and supraspinal mechanisms. These include opioids, which desensitize peripheral nociceptors and reduce proinflammatory cytokines peripherally and in the spinal cord, and serotonin and norepinephrine, which decrease spinal N-methyl-D-aspartate receptor subunit GluN1 phosphorylation. Additional studies suggest that electroacupuncture, when combined with low dosages of conventional analgesics, provides effective pain management which can forestall the side effects of often-debilitating pharmaceuticals.

Evaluation of the anti-Schistosoma mansoni activity of thiosemicarbazones and thiazoles

Schistosomiasis is a chronic and debilitating disease caused by a trematode of the genus Schistosoma and affects over 207 million people. Chemotherapy is the only immediate recourse for minimizing the prevalence of this disease and involves predominately the administration of a single drug, praziquantel (PZQ). Although PZQ has proven efficacy, there is a recognized need to develop new drugs as schistosomicides since studies have shown that repeated use of this drug in areas of endemicity may cause a temporary reduction in susceptibility in isolates of Schistosoma mansoni. Hydrazones, thiosemicarbazones, phthalimides, and thiazoles are thus regarded as privileged structures used for a broad spectrum of activities and are potential candidates for sources of new drug prototypes. The present study determined the in vitro schistosomicidal activity of 10 molecules containing these structures. During the assays, parameters such motility and mortality, oviposition, morphological changes in the tegument, cytotoxicity, and immunomodulatory activity caused by these compounds were evaluated. The results showed that compounds formed of thiazole and phthalimide led to higher mortality of worms, with a significant decline in motility, inhibition of pairing and oviposition, and a mortality rate of 100% starting from 144 h of exposure. These compounds also stimulated the production of nitric oxide and tumor necrosis factor alpha (TNF-α), thereby demonstrating the presence of immunomodulatory activity. The phthalyl thiazole LpQM-45 caused significant ultrastructural alterations, with destruction of the tegument in both male and female worms. According to the present study, phthalyl thiazole compounds possess antischistosomal activities and should form the basis for future experimental and clinical trials.

Endogenous opiates and behavior: 2010

This paper is the thirty-third consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2010 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).

Anti-inflammatory and antinociceptive activities of indole-imidazolidine derivatives

Non-steroidal anti-inflammatory drugs (NSAIDs) represent a group of approximately 50 different medicines that are widely prescribed for the management of inflammation and that exhibit variable anti-inflammatory, anti-pyretic and analgesic activities. Most NSAIDs also exhibit a shared set of adverse effects, particularly related to gastrointestinal complications; thus, the development of new drugs for the treatment of chronic inflammation and pain continues to be an issue of high interest. Hydantoin and indole derivatives are reported to possess various pharmacological effects, including anti-inflammatory and analgesic activities. Therefore, the aim of this study was to evaluate the potential anti-inflammatory and antinociceptive activities of hybrid molecules containing imidazole and indole nuclei. The anti-inflammatory activities of 5-(1H-Indol-3-yl-methylene)-2-thioxo-imidazolidin-4-one (LPSF/NN-56) and 3-(4-Bromo-benzyl)-5-(1H-indol-3-yl-methylene)-2thioxo-imidazolidin-4-one (LPSF/NN-52) were evaluated using air pouch and carrageenan-induced peritonitis models as well as an acetic acid-induced vascular permeability model followed by IL-1β and TNF-α quantification. To evaluate the antinociceptive activities of the compounds, acetic acid-induced nociception, formalin and hot plate tests were also performed. The anti-inflammatory activities of the compounds were evidenced by a reduction in both leukocyte migration and the release of TNF-α and IL-1β in air pouch and peritonitis models. Upon acetic acid-induced nociception, a decrease in the level of abdominal writhing in the groups treated with LPSF/NN-52 (52.1%) or LPSF/NN-56 (63.1%) was observed. However, in the hot plate test, none of the derivatives tested exhibited an inhibition of nociception. These results indicate that the compounds tested exhibited promising anti-inflammatory and antinociceptive activities that likely involved the modulation of the immune system.