Study of the correlation between blood cholinesterases activity, urinary dialkyl phosphates, and the frequency of micronucleated polychromatic erythrocytes in rats exposed to disulfoton

Organophosphates (OPs) are widely used as pesticides, and its urinary metabolites as well as the blood cholinesterases (ChEs) activity have been reported as possible biomarkers for the assessment of this pesticide exposure. Moreover, the OPs can induce mutagenesis, and the bone marrow micronucleus test is an efficient way to assess this chromosomal damage. This paper reports a study carried out to verify the correlation among the disulfoton exposure, blood ChEs activity, urinary diethyl thiophosphate (DETP), and diethyl dithiophosphate (DEDTP), as well as micronucleated polychromatic erythrocytes (MNPCEs) frequency. Four groups of rats (n=12) were exposed to disulfoton at 0, 2.8, 4.7, and 6.6 mg kg-1 body weight. The blood ChEs activity, urinary DETP and DEDTP concentrations, and MNPCEs frequency were determined. It was observed that the plasmatic and erythrocytary ChEs activity decreased from 2.9% to 0.5% and from 35.9 to 3.3%, respectively, when the disulfoton dose was increased from 0 to 6.6 mg kg-1 (correlation of 0.99). Urinary DETP and DEDTP concentrations, as well as the MNPCEs frequency, increased from 0 to 6.58 µg mL-1, from 0 to 0.04 µg mL-1, and from 0 to 1.4%, respectively, when the disulfoton dose was increased from 0 to 6.58 mg kg-1 body weight.Os organofosforados (OPs) são amplamente usados como praguicidas e a atividade da colinesterase sanguínea bem como os metabólitos urinários desses praguicidas têm sido reportados como biomarcadores eficazes para avaliar casos de exposição. Além disso, os OPs podem induzir mutagênese e o teste de micronúcleo de medula óssea é uma boa alternativa para avaliar os danos cromossômicos. Esse artigo reporta um estudo sobre a correlação entre a exposição a dissulfoton, a atividade da colinesterase sanguínea, a excreção urinária de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos em eritrócitos policromáticos. Quatro grupos de ratos (n=12) foram expostos a dissulfotom nas doses de 0, 2,8, 4,7, e 6,6 mg kg-1 de peso corpóreo. A atividade da colinesterase sanguínea as concentrações urinárias de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos foram determinadas. Os resultados demonstraram que as atividades da colinesterase plasmática e eritrocitária diminuíram de 2,9 para 0,5% e de 35,9 para 3,3% , respectivamente, quando a dose de dissulfoton foi aumentada de 0 para 6,6 mg kg-1 (correlação de 0,99). As concentrações urinárias de dietil tiofosfato e dietil ditiofosfato bem como a frequência de micronúcleos aumentaram de 0 a 6,56 µg mL-1, 0 a 0.04 µg mL-1 e de 0 a 1.4%, respectivamente, quando a dose de dissulfotom foi aumentada de 0 a 6,58 mg kg-1

Design, synthesis, and biological evaluation of new thalidomide–donepezil hybrids as neuroprotective agents targeting cholinesterases and neuroinflammation

A new series of eight multifunctional thalidomide–donepezil hybrids were synthesized based on the multi target-directed ligand strategy and evaluated as potential neuroprotective, cholinesterase inhibitors and anti neuroinflammatory agents against neurodegenerative diseases. A molecular hybridization approach was used for structural design by combining the N-benzylpiperidine pharmacophore of donepezil and the isoindoline 1,3-dione fragment from the thalidomide structure. The most promising compound, PQM-189 (3g), showed good AChE inhibitory activity with an IC50 value of 3.15 μM, which was predicted by docking studies as interacting with the enzyme in the same orientation observed in the AChE–donepezil complex and a similar profile of interaction. Additionally, compound 3g significantly decreased iNOS and IL-1β levels by 43% and 39%, respectively, after 24 h of incubation with lipopolysaccharide. In vivo data confirmed the ability of 3g to prevent locomotor impairment and changes in feeding behavior elicited by lipopolysaccharide. Moreover, the PAMPA assay evidenced adequate blood–brain barrier and gastrointestinal tract permeabilities with an Fa value of 69.8%. Altogether, these biological data suggest that compound 3g can treat the inflammatory process and oxidative stress resulting from the overexpression of iNOS and therefore the increase in reactive nitrogen species, and regulate the release of pro-inflammatory cytokines such as IL-1β. In this regard, compound PQM-189 (3g) was revealed to be a promising neuroprotective and anti-neuroinflammatory agent with an innovative thalidomide–donepezil-based hybrid molecular architectur

Avaliação cardiovascular e do tempo de mergulho em Lithobates catesbeianus após a manipulação de gases intrapulmonares

O objetivo desse estudo foi avaliar o efeito da administração de gases intrapulmonares sobre os parâmetros cardiovasculares e o tempo de submersão voluntária em rã (Lithobates catesbeianus). A importância de estudos como este é ampliar o conhecimento sobre o controle e comportamento no mergulho de anfíbios. Os experimentos foram iniciados após a L. catesbeianus ser mantida no laboratório por, no mínimo, 24 horas. Foram medidas pressão arterial média (PAM, mmHg), pressão sistólica (Psis, mmHg), pressão diastólica (Pdis, mmHg), pressão de pulso (mmHg), freqüência cardíaca (FC, bpm) e tempo de submersão voluntária. O período de emersão, submersão e pós-submersão previamente à administração dos gases intrapulmonares foram utilizados como controle. Nas submersões subseqüentesforam administrados os gases: A) mistura normóxica (21% O2 / 0,3% CO2/ N2 balanço; B) mistura hipóxica e hipercapnica (14% O2 / 7% CO2/ N2 balanço); C) gás hiperóxico (100% O2) e D) 100% N2. Dos parâmetros cardiovasculares analisados, somente a FC alterou, diminuindo em torno de 20% na submersão, no entanto essa redução ocorreu antes da administração dos gases intrapulmonares. Foi observado aumento significativo do tempo de mergulho após a administração do gás hiperóxico. Pode-se concluir dos nossos resultados que o tempo de mergulho voluntário em L. catesbeianus pode ser longo se for alta a tensão de O2 pulmonar

Testing the correlation between experimentally-induced hypothyroidism during pregnancy and autistic-like symptoms in the rat offspring

Thyroid hormones are important for the development of the central nervous system. Since the fetal thyroid gland is not functioning until mid-gestation, transport of maternal thyroid hormones across the placenta is essential during the early phases of gestation. Maternal thyroid deficiency has been associated with a higher incidence of neurodevelopmental disorders in the newborns. The relationship between maternal hypothyroidism and the onset of autism spectrum disorders (ASD) in the offspring, however, is still debated. To address this issue, we used a validated animal model of prenatal hypothyroidism based on the administration of the thyroid peroxidase inhibitor methimazole (MMI, 0.02 g/100 ml in tap water) to rat dams from gestational day 9 up to delivery. The offspring was tested in behavioral tasks during infancy (PNDs 5, 9, 13) and adolescence (PND 35-40) to capture some of the core and associated symptoms of ASD. MMI-exposed pups were able to vocalize as controls when separated from the nest, and showed intact social discrimination abilities in the homing behavior test. At adolescence, the offspring from both sexes did not show an anxious-phenotype in the elevated plus maze and showed intact object recognition. However, MMI-exposed male rats showed increased novelty-directed exploratory behaviors: they solicited their partner to play more and showed more interest for novel rather than familiar objects compared to control rats. Our results show that prenatal MMI-induced hypothyroidism does not cause in the rat offspring behaviors that resemble core and associated ASD symptoms, like deficits in communication and social interaction and anxiety

Carbon monoxide and nitric oxide modulate hyperosmolality-induced oxytocin secretion by the hypothalamus in vitro

OT (oxytocin) is secreted from the posterior pituitary gland, and its secretion has been shown to be modulated by NO (nitric oxide). In rats, OT secretion is also stimulated by hyperosmolarity of the extracellular fluid. Furthermore, NOS (nitric oxide synthase) is located in hypothalamic areas involved in fluid balance control. In the present study, we evaluated the role of the NOS/NO and HO (haem oxygenase)/CO (carbon monoxide) systems in the osmotic regulation of OT release from rat hypothalamus in vitro. We conducted experiments on hypothalamic fragments to determine the following: (i) whether NO donors and NOS inhibitors modulate OT release and (ii) whether the changes in OT response occur concurrently with changes in NOS or HO activity in the hypothalamus. Hyperosmotic stimulation induced a significant increase in OT release that was associated with a reduction in nitrite production. Osmotic stimulation of OT release was inhibited by NO donors. NOS inhibitors did not affect either basal or osmotically stimulated OT release. Blockade of HO inhibited both basal and osmotically stimulated OT release, and induced a marked increase in NOS activity. These results indicate the involvement of CO in the regulation of NOS activity. The present data demonstrate that hypothalamic OT release induced by osmotic stimuli is modulated, at least in part, by interactions between NO and CO

Serotonergic mechanisms of the lateral parabrachial nucleus in renal and hormonal responses to isotonic blood volume expansion

This study investigated the involvement of serotonergic mechanisms of the lateral parabrachial nucleus (LPBN) in the control of sodium (Na+) excretion, potassium (K+) excretion, and urinary volume in unanesthetized rats subjected to acute isotonic blood volume expansion (0.15 M NaCl, 2 ml/100 g of body wt over 1 min) or control rats. Plasma oxytocin (OT), vasopressin (VP), and atrial natriuretic peptide (ANP) levels were also determined in the same protocol. Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used. In rats treated with vehicle in the LPBN, blood volume expansion increased urinary volume, Na+ and K+ excretion, and also plasma ANP and OT. Bilateral injections of serotonergic receptor antagonist methysergide (1 or 4 mu g/200 eta 1) into the LPBN reduced the effects of blood volume expansion on increased Na+ and K+ excretion and urinary volume, while LPBN injections of serotonergic 5-HT2a/HT2c receptor agonist, 2.5-dimetoxi-4-iodoamphetamine hydrobromide (DOI;1 or 5 mu g/200 eta 1) enhanced the effects of blood volume expansion on Na+ and K+ excretion and urinary volume. Methysergide (4 mu g) into the LPBN decreased the effects of blood volume expansion on plasma ANP and OT, while DOI (5 mu g) increased them. The present results suggest the involvement of LPBN serotonergic mechanisms in the regulation of urinary sodium, potassium and water excretion, and hormonal responses to acute isotonic blood volume expansion

Evaluation of anxiolytic-like effect of 7-epiclusianone isolated from Garcinia brasiliensis in mice

Garcinia brasiliensis Mart., Clusiaceae, species became the target of studies for some years because it has several compounds including polyprenylated benzophenones, as 7-epiclusianone. This benzophenone has several properties, such as leishmanicidal, anti-inflammatory and antinociceptive effects, however still did not be studied anxiolytic activity. For this, the open field and elevated plus maze tests were used in order to evaluate the effect of administration of 7-epiclusianone (isolated from G. brasiliensis) on behavioral performance. Swiss male mice (n = 10 per group) were pre-treated with vegetable oil (10 ml/kg; i.p.) or 7-epiclusianone (1, 3 or 10 mg/kg, i.p.) or diazepam (0.2 mg/kg, i.p.). After 1 h, the animals were submitted to the open field and elevated plus maze tests. The administration of 7-epiclusianone exerted a possible anxiolytic effect in the open field, increased the number of central crossings and anti-tigmotactic effect. In pre-treated group with 7-epiclusianone (10 mg/kg) was also possible to determine a possible anxiolytic effect in the elevated plus maze due to increased permanence of animals in the open arms. The results suggest a possible anxiolytic-like effect presented by the 7-epiclusianone and suggest its potential for the treatment of anxiety. Keywords: Polyprenylated benzophenones, 7-Epiclusianone, Anxiet