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1.
PLoS One ; 15(9): e0239270, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32936829

RESUMO

In a between-subject comparison of two memantine administration schedules we observed that treatment with the NMDA receptor antagonist memantine before testing sessions reduced ingestion of a 10% sucrose solution in rats, due to reduced licking burst size, thus suggesting a blunted hedonic response. Conversely, daily post-session administration reduced burst number, indicating a reduced level of behavioural activation, likely due to the development of conditioned taste aversion (CTA). In this study, the effect of pre-session and post-session memantine administration was investigated within-subjects. Memantine was administered in daily intraperitoneal injections for 13 days, on alternate days, either 1-h before-"before testing" sessions-or immediately after a 30-min session-"after testing" sessions. The effects on the microstructure of licking for a 10% sucrose solution were examined in the course of treatment and for 21 days after treatment discontinuation. The results show reduced burst size in the "before testing" sessions, without effects on the intra-burst lick rate, an index of motoric effects. Moreover, burst number was reduced since the third session of both administration conditions until the end of treatment. Interestingly, the effect of memantine of reducing the activation of ingestive behaviour was less pronounced in this study with respect to that observed with the previous study post-session administration schedule, in spite of the longer treatment. This apparent paradox might be explained if one considers these effects as instances of a memory-related effect, such as the development of CTA. In the framework of this hypothesis, the "before testing" sessions, not being followed by memantine administration, can be considered as extinction sessions performed every other day. Moreover, the animals treated with memantine at the highest dose failed to recover to pre-treatment ingestion levels 21 days after treatment discontinuation, while the animals treated after testing sessions in the previously published study showed a complete recovery well before the 15th day test. Within the same interpretative framework, this might depend by the reduced number and frequency of the extinction trials-i.e. the number of the sessions run after treatment discontinuation-in the present study. These results provide further support to the conclusion that memantine administration before sessions reduce burst size, an effect which is likely due to blockade of NMDA receptors occurring during behavioural testing. The observation that this effect can be obtained even in absence of a reduced intra-burst lick rate, which rules out the involvement of motor impairment, provides an important piece of evidence in support to the interpretation of this effect as a blunted hedonic response. Moreover, these results provide further evidence that burst number reduction is due to a memory-related effect induced by memantine administration after sessions.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Memantina/farmacologia , Memória/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Animais , Condicionamento Clássico/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Ingestão de Alimentos , Humanos , Memantina/efeitos adversos , Memória/fisiologia , Ratos , Receptores de N-Metil-D-Aspartato/genética
2.
Life Sci ; 259: 118224, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32768574

RESUMO

AIM: The aim of this study was to evaluate the effects of maternal exposure to a high-fat diet associated with neonatal administration of kaempferol on somatic growth, biochemical profile and feeding behavior in offspring. MATERIALS AND METHODS: Wistar rats were distributed according to diet during pregnancy and lactation into Control (C; 3.4 kcal/g; 12% kcal/lipids) or High-fat (HFD; 4.6 kcal/g; 51% kcal/lipids) groups. In the offspring, vehicle (V) or kaempferol (K, 1 mg/kg) were administered from the 8th until the 21st postnatal day (PND). Maternal body weight (BW), caloric intake and adiposity were measured. In the offspring, somatic growth parameters were evaluated on the 7th, 14th, 21st, 25th and 30th PND, except for BW, which was measured from the 8th to the 21st and from the 25th to the 30th PND. Feeding behavior was assessed by food intake and behavioral satiety sequence (BSS) on the 30th PND. The biochemical profile and relative weight of adipose tissue of offspring were also measured. KEY FINDINGS: Dams exposed to HFD showed no difference in body weight and caloric intake but exhibited increased adiposity. Neonatal administration of kaempferol increased body weight after weaning and somatic growth in the offspring of HFD dams. Neonatal kaempferol also reduced adiposity and serum creatinine levels in offspring. Neither maternal diet nor kaempferol altered offspring feeding behavior. SIGNIFICANCE: Neonatal administration of kaempferol promotes increased somatic growth post-weaning, reduces adiposity, and does not alter feeding behavior in offspring from high-fat dams.


Assuntos
Adiposidade/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Quempferóis/farmacologia , Tecido Adiposo , Animais , Animais Recém-Nascidos/metabolismo , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Ingestão de Energia/efeitos dos fármacos , Feminino , Quempferóis/metabolismo , Lactação/efeitos dos fármacos , Masculino , Exposição Materna/efeitos adversos , Fenômenos Fisiológicos da Nutrição Materna , Obesidade/tratamento farmacológico , Gravidez , Ratos , Ratos Wistar , Desmame
3.
Aquat Toxicol ; 227: 105587, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32841885

RESUMO

Among the various environmental disturbances caused by wildfires, their impacts within burnt areas and on the downhill aquatic ecosystems has been receiving increased attention. Post-fire rainfalls and subsequent runoffs play an important role in transporting ash and soil to aquatic systems within the burnt areas. These runoffs can be a diffuse source of toxic substances such as metals. The present work aims at assessing the effects of ash-loaded runoff on feeding rates of three representative aquatic invertebrates (Daphnia magna, Corbicula fluminea and Atyaephyra desmarestii) and the mosquitofish, Gambusia holbrooki, through post-exposure feeding inhibition bioassays carried out in-situ and in the laboratory using water collected from the experimental field sites. Four sites were selected in a partially burnt basin for bioassay deployment and sample collection: one site upstream of the burnt area (RUS); three sites receiving runoff directly from the burnt area, one immediately downstream of the burnt area (RDS) and two in permanent tributary streams within the burnt area (BS1 and BS2). The in-situ exposure lasted four days and began following the first post-fire major rain events. At sites affected by the wildfire, post-exposure feeding rates for D. magna, A. desmarestii and G. holbrooki were lower, which is consistent with the highest levels of metals found at these sites compared to the unaffected site, although the individual concentrations of each metal were generally below corresponding ecological safety benchmarks. Thus, interactions between metals and/or between metals and other environmental parameters certainly played a role in modulating the ecotoxic effects of the runoffs; this was further supported by a Toxic Units Summation exercise. Even if direct causal links between the ecotoxicological effects observed in D. magna, A. desmarestii and G. holbrooki and the physicochemical parameters of the water samples could not be established, the results suggest an important role of major and trace elements in explaining post-exposure feeding rate variation.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Cinza de Carvão/toxicidade , Comportamento Alimentar/efeitos dos fármacos , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Incêndios Florestais , Animais , Organismos Aquáticos/fisiologia , Bioensaio , Corbicula/efeitos dos fármacos , Ciprinodontiformes/fisiologia , Daphnia/efeitos dos fármacos , Ecossistema , Ecotoxicologia , Água Doce/química , Modelos Teóricos , Portugal , Oligoelementos/toxicidade
4.
Life Sci ; 258: 118192, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32781062

RESUMO

The present study was conducted to identify possible health - promoting effects of wogonin (Wog) on testicular dysfunction in rats caused by cadmium. Pre-treatment of cadmium chloride (Cd: 5 mg/kg b.wt.) administered rats with wogonin (10 mg/kg b.wt) resulted in significant improvement in Cd-induced decrease in body and organ (testes and epididymides) weights. Wogonin treatment significantly improved Cd-induced reduction in sperm quality and quantity, steroidogenic gene (SFI, StAR, CYP11A1, 3ß-HSD, CYP17A1 and 17ß-HSD) and protein (SF1, StAR and CYP17A1) expressions and serum testosterone levels. Wogonin treatment provided significant protection to Cd-induced aggression in testicular oxidative (elevated levels of MDA) and anti-oxidative (diminished activities of SOD, CAT and GPx) status. Wog significantly up-regulated mRNA levels of Nrf2, NQO1 and HO-1 and down-regulation of Keap1 in cadmium treated testes. Wogonin administration significantly suppressed Cd-stimulated increase in inflammatory reactions (increase in NF-κB p65 DNA, p-IKKß, TNF-α levels and decrease in IL-10 levels). Wogonin prevented apoptotic damage by enhanced protein distribution of caspase-9, caspase-3, and Bax due to Cd exposure. Furthermore, Wogonin presented significant protection to histo-morphometric changes resulted after Cd administration. Taken together, the findings of this study provided clear evidence of the therapeutic potential of Cd-induced testicular toxicity at least partly due to its antioxidant, anti-inflammatory and anti-apoptotic properties.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Cádmio/toxicidade , Flavanonas/farmacologia , Substâncias Protetoras/farmacologia , Transdução de Sinais , Testículo/patologia , Animais , Biomarcadores/metabolismo , Peso Corporal/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Epididimo/efeitos dos fármacos , Epididimo/patologia , Comportamento Alimentar/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônios/sangue , Inflamação/patologia , Masculino , Oxirredução , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Espermatogênese/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Espermatozoides/metabolismo , Esteroides/metabolismo , Testículo/efeitos dos fármacos , Testículo/metabolismo
5.
Chemosphere ; 261: 127720, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32721693

RESUMO

Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) preys on insect pests in eucalyptus plantations where it can be exposed to insecticides used in pest control. The effect of insecticides on non-target natural enemies requires further study. The objective of the present study was to evaluate the side-effects of Bacillus thuringiensis (Bt), permethrin, tebufenozide and thiamethoxam on third instar nymphs of the predator P. nigrispinus in the laboratory. The toxicity of insecticides for this insect was determined by estimating their lethal concentrations. Podisus nigrispinus behavior after exposure to insecticides was analyzed using a video tracking system and the respiratory rate with a respirometer. Prey/nymph consumption was assessed after 24 h of starvation. The preference of P. nigrispinus nymphs, for prey treated or not with the insecticides, was evaluated in free choice tests. The insecticides Bt [LC50 = 1.10(0.83-1.46) mg mL-1], permethrin [LC50 = 0.25(0.17-0.34) mg mL-1], tebufenozide [LC50 = 5.71(4.17-7.57) mg mL-1] and thiamethoxam [LC50 = 0.04(0.02-0.06) mg mL-1] are toxic to P. nigrispinus nymphs. Bt and the insecticides tebufenozide, permethrin and thiamethoxam reduced the respiratory rate of P. nigrispinus. The insecticides permethrin, tebufenozide and thiamethoxam affect the locomotion of this insect's nymphs. Prey treated with Bt, permethrin and thiamethoxam are less preferred by P. nigrispinus. The survival of the nymphs of this predator was 93.3%, 66.7%, 56.6%, 0% and 0% in the control, tebufenozide, Bt, permethrin and thiamethoxam treatments, respectively. In addition, the reduction of prey consumption, treated with neurotoxic insecticides, reduces the predatory potential of this natural enemy. Bt and tefubenozide present low toxicity for P. nigrispinus, but the neurotoxic products have low compatibility with this natural enemy and, therefore, are not recommended, with this predator in the management of forest insect pests.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Heterópteros/efeitos dos fármacos , Inseticidas/toxicidade , Ninfa/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Animais , Bacillus thuringiensis/efeitos dos fármacos , Bacillus thuringiensis/crescimento & desenvolvimento , Brasil , Eucalyptus/crescimento & desenvolvimento , Controle de Pragas , Controle Biológico de Vetores
6.
Aquat Toxicol ; 226: 105564, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32683169

RESUMO

Millions of pharmaceuticals are prescribed each year. Wastewater treatment plants fail to remove all pharmaceuticals from discharge leading to detectable concentrations entering aquatic ecosystems where the compounds can encounter nontarget organisms. Selective serotonin reuptake inhibitor (SSRI) class of antidepressants interact with transporters in the brain and peripheral nervous system to change serotonin levels in the synapse. Sublethal exposure to SSRIs can impact fish feeding behaviors, which can have impacts on ecological fitness. We exposed hybrid striped bass (Morone saxatilis x Morone chrysops) to low, medium, and high concentrations of sertraline (4.5 ± 0.84 µg/L, 35.4 ± 2.18 µg/L, and 96.8 ± 6.4 µg/L) over six days with six additional recovery days. Concentrations were chosen to compare results with a mixture study previously completed in our lab. Every three days we tracked how long each bass took to consume four fathead minnows (Pimephales promelas) and conducted destructive sampling to obtain brain and plasma samples. Brain and plasma samples were analyzed for sertraline levels and we calculated whole brain serotonin levels. During the exposure period, bass showed an increased time to capture prey, but time to capture prey returned to control levels during the six-day recovery period. Sertraline was detected in brain and plasma during the duration of the experiment, though not always in a dose-dependent fashion. While we demonstrated a relationship between time to capture prey and decrease whole brain serotonin levels, the decrease in time to capture prey during the recovery period suggests the serotonin levels in the brain are not solely responsible for the outward behavioral expression observed.


Assuntos
Bass/fisiologia , Química Encefálica/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Inibidores de Captação de Serotonina/toxicidade , Sertralina/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bass/sangue , Bass/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Ecossistema , Comportamento Alimentar/efeitos dos fármacos , Serotonina/metabolismo
7.
PLoS One ; 15(6): e0228830, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32516338

RESUMO

The food environment can interact with cognitive processing and influence eating behaviour. Our objective was to characterize the impact of implicit olfactory priming on inhibitory control towards food, in groups with different weight status. Ninety-one adults completed a modified Affective Shifting Task: they had to detect target stimuli and ignore distractor stimuli while being primed with non-attentively perceived odours. We measured reactivity and inhibitory control towards food pictures. Priming effects were observed on reactivity: participants with overweight and obesity were slower when primed with pear and pound cake odour respectively. Common inhibitory control patterns toward foods were observed between groups. We suggest that non-attentively perceived food cues influence bottom-up processing by activating distinguished mental representations according to weight status. Also, our data show that cognitive load influences inhibitory control toward foods. Those results contribute to understanding how the environment can influence eating behaviour in individuals with obesity.


Assuntos
Sinais (Psicologia) , Alimentos , Inibição Psicológica , Odorantes , Adulto , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação/efeitos dos fármacos , Adulto Jovem
8.
J Neurosci ; 40(27): 5273-5282, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32457071

RESUMO

The mesolimbic dopaminergic system exerts a crucial influence on incentive processing. However, the contribution of dopamine in dynamic, ecological situations where reward rates vary, and decisions evolve over time, remains unclear. In such circumstances, current (foreground) reward accrual needs to be compared continuously with potential rewards that could be obtained by traveling elsewhere (background reward rate), to determine the opportunity cost of staying versus leaving. We hypothesized that dopamine specifically modulates the influence of background, but not foreground, reward information when making a dynamic comparison of these variables for optimal behavior. On a novel foraging task based on an ecological account of animal behavior (marginal value theorem), human participants of either sex decided when to leave locations in situations where foreground rewards depleted at different rates, either in rich or poor environments with high or low background reward rates. In line with theoretical accounts, people's decisions to move from current locations were independently modulated by changes in both foreground and background reward rates. Pharmacological manipulation of dopamine D2 receptor activity using the agonist cabergoline significantly affected decisions to move on, specifically modulating the effect of background reward rates. In particular, when on cabergoline, people left patches in poor environments much earlier. These results demonstrate a role of dopamine in signaling the opportunity cost of rewards, not value per se. Using this ecologically derived framework, we uncover a specific mechanism by which D2 dopamine receptor activity modulates decision-making when foreground and background reward rates are dynamically compared.SIGNIFICANCE STATEMENT Many decisions, across economic, political, and social spheres, involve choices to "leave". Such decisions depend on a continuous comparison of a current location's value, with that of other locations you could move on to. However, how the brain makes such decisions is poorly understood. Here, we developed a computerized task, based around theories of how animals make decisions to move on when foraging for food. Healthy human participants had to decide when to leave collecting financial rewards in a location, and travel to collect rewards elsewhere. Using a pharmacological manipulation, we show that the activity of dopamine in the brain modulates decisions to move on, with people valuing other locations differently depending on their dopaminergic state.


Assuntos
Tomada de Decisões/fisiologia , Dopamina/fisiologia , Comportamento Alimentar/fisiologia , Adulto , Cabergolina/farmacologia , Tomada de Decisões/efeitos dos fármacos , Agonistas de Dopamina/farmacologia , Método Duplo-Cego , Meio Ambiente , Comportamento Alimentar/efeitos dos fármacos , Feminino , Humanos , Masculino , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Receptores de Dopamina D2/efeitos dos fármacos , Receptores de Dopamina D2/fisiologia , Recompensa , Adulto Jovem
9.
Proc Natl Acad Sci U S A ; 117(22): 12017-12028, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32434917

RESUMO

Synthetic chemical elicitors, so called plant strengtheners, can protect plants from pests and pathogens. Most plant strengtheners act by modifying defense signaling pathways, and little is known about other mechanisms by which they may increase plant resistance. Moreover, whether plant strengtheners that enhance insect resistance actually enhance crop yields is often unclear. Here, we uncover how a mechanism by which 4-fluorophenoxyacetic acid (4-FPA) protects cereals from piercing-sucking insects and thereby increases rice yield in the field. Four-FPA does not stimulate hormonal signaling, but modulates the production of peroxidases, H2O2, and flavonoids and directly triggers the formation of flavonoid polymers. The increased deposition of phenolic polymers in rice parenchyma cells of 4-FPA-treated plants is associated with a decreased capacity of the white-backed planthopper (WBPH) Sogatella furcifera to reach the plant phloem. We demonstrate that application of 4-PFA in the field enhances rice yield by reducing the abundance of, and damage caused by, insect pests. We demonstrate that 4-FPA also increases the resistance of other major cereals such as wheat and barley to piercing-sucking insect pests. This study unravels a mode of action by which plant strengtheners can suppress herbivores and increase crop yield. We postulate that this represents a conserved defense mechanism of plants against piercing-sucking insect pests, at least in cereals.


Assuntos
Acetatos/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Flavonoides , Hemípteros , Imunidade Vegetal/efeitos dos fármacos , Animais , Bioensaio , Produtos Agrícolas/efeitos dos fármacos , Flavonoides/análise , Flavonoides/metabolismo , Herbivoria , Hordeum/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/metabolismo , Oryza/efeitos dos fármacos , Peroxidases/análise , Peroxidases/metabolismo , Controle de Pragas/métodos , Folhas de Planta/química , Triticum/efeitos dos fármacos
10.
Artigo em Inglês | MEDLINE | ID: mdl-32415362

RESUMO

Recent studies have reported interspecific differences in how bee species respond to various stressors. Evaluating the exposure and responses of different bee species to plant protection products is considered an essential part of their risk assessment. This study was conducted to assess the impacts of thiacloprid-prochloraz mixture on buff-tailed bumblebees (Bombus terrestris) and red mason bees (Osmia bicornis) in a worst-case scenario under semi-field conditions. Bumblebee colonies or solitary bee trap nests were confined in tunnels with flowering oilseed rape. The recommended maximum application rates of 72 g thiacloprid/ha and 675 g prochloraz/ha were applied as a tank mixture during bee flight in full flowering oilseed rape. Several parameters such as flight and foraging activity, population parameters, and exposure level were investigated. Our results show adverse effects of the combination of thiacloprid and prochloraz on the reproductive performance of red mason bees. The number of cocoons produced by O. bicornis was significantly reduced in the treatment compared to the control group. Regarding bumblebees, we found no effects of the thiacloprid-prochloraz mixture on any observed parameters of colony development. The maximum detected concentrations of both active substances three days after application were higher in O. bicornis pollen mass compared to B. terrestris stored pollen. We conclude that this worst-case scenario of thiacloprid-prochloraz exposure poses a high risk to solitary bees and thus the use of such mixture should be restricted.


Assuntos
Abelhas/efeitos dos fármacos , Voo Animal/efeitos dos fármacos , Imidazóis/administração & dosagem , Inseticidas/administração & dosagem , Neonicotinoides/administração & dosagem , Tiazinas/administração & dosagem , Animais , Comportamento Alimentar/efeitos dos fármacos , Alemanha , Dinâmica Populacional , Reprodução
11.
Ecotoxicol Environ Saf ; 197: 110573, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32278825

RESUMO

Antibiotics had been paid more and more attention to their toxicity to non-target aquatic organisms in the aquatic environment. As azithromycin (AZI) was an important antibiotic pollutant in water, its toxicity to aquatic organisms had been investigated. In this study, the potential aquatic ecological risk of AZI was identified by assessing the toxicity on the feeding behavior and physiological function of Daphnia magna (D. magna) under the different exposure pathways (aqueous phase exposure vs. food phase exposure). For the food Chlorella pyrenoidosa (C. pyrenoidosa), AZI could inhibit the growth and nutrition accumulation with concentration- and time-response relationship. For D. magna, the feeding behavior was inhibited by AZI under the aqueous phase exposure pathway. However, the feeding behavior was inhibited firstly and then reversed into promotion in the low and medium concentration groups and was continually promoted in the high concentration group under the food phase exposure pathway. The accumulation of polysaccharides and total protein were decreased in D. magna n the high concentration group under the aqueous phase exposure pathway, while the accumulation of polysaccharides and crude fat were decreased in the high concentration group under the food phase exposure pathway. The activity of amylase (AMS) and trypsin in D. magna were decreased after exposure to AZI under the aqueous phase exposure pathway. On the other hand, the activity of AMS in the medium and high concentration groups was decreased under the food phase exposure pathway, but the activity of trypsin was decreased in the medium concentration group and increased in the high concentration group. The levels of ROS in D. magna were also measured and increased in both exposure pathways except in the low concentration group under the food phase exposure pathway, indicating the oxidative stress injury of D. magna. Our results showed that AZI could affect the digestive enzyme activities and oxidative stress-antioxidative system, ultimately leading to the change of D. magna's feeding behavior and nutrition accumulation. These results also provided a comprehensive perspective to evaluate the toxic effects of non-lethal dose antibiotics to non-target aquatic organisms via different exposure pathways.


Assuntos
Azitromicina/toxicidade , Daphnia/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Nutrientes/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Azitromicina/metabolismo , Chlorella/metabolismo , Daphnia/metabolismo , Daphnia/fisiologia , Exposição Dietética/efeitos adversos , Exposição Ambiental/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo
12.
Psychopharmacology (Berl) ; 237(7): 2103-2110, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32303779

RESUMO

RATIONALE: Effort-related choice tasks are used to study aspects of motivation in both rodents and humans (Der-Avakian and Pizzagalli Biol Psychiatry 83(11):932-939, 2018). Various dopaminergic manipulations and antidepressant treatments can shift responding to these tasks (Randall et al. Int J Neuropsychopharmacol 18(2), 2014; Yohn et al. Psychopharmacology 232(7):1313-1323, 2015). However, while chronic stress can precipitate mood disorders in humans, there is relatively little known about whether chronic stress elicits maladaptive behaviors in rodent effort-related choice tasks. OBJECTIVES: Chronic corticosterone (CORT) elicits an increase in negative maladaptive behaviors in male mice (David et al. Neuron 62(4):479-493, 2009; Gourley et al. Biol Psychiatry 64(10):884-890, 2008; Olausson et al. Psychopharmacology 225(3):569-577, 2013). We hypothesized that chronic CORT administration to male mice would reduce motivation for a higher effort, higher reward option, and shift responding to a less effortful, but a lesser reward. METHODS: Adult male C57BL/6J mice were administered either vehicle (n = 10) or CORT (n = 10) (~ 9.5 mg/kg/day) in their drinking water for 4 weeks, and then throughout all behavioral experiments (15 weeks total), and were tested in a Y-Maze barrier task and a fixed ratio concurrent (FR/chow) choice task. RESULTS: Chronic CORT reduced Y-maze HR arm choice when more effort was required to obtain the 4 food pellets (15-cm barrier in the high-reward (HR) arm, p < 0.001; 20-cm barrier in HR arm, p < 0.001) and shifted choice to the low reward (LR) arm where only 2 pellets were available. Chronic CORT also reduced lever pressing for food pellets in FR30/chow sessions of the concurrent choice task (p = 0.009), without impacting lab chow consumed. CONCLUSIONS: Chronic stress induces maladaptive shifts in effort-related choice behavior in the Y-maze barrier task in male mice. Furthermore, males subjected to chronic CORT administration show reduced lever pressing in FR30/chow sessions where lab chow is concurrently available. These data demonstrate that chronic corticosterone reduces motivation to work for and obtain a highly rewarding reinforcer when a lesser reinforcer is concurrently available.


Assuntos
Comportamento de Escolha/efeitos dos fármacos , Corticosterona/administração & dosagem , Aprendizagem em Labirinto/efeitos dos fármacos , Motivação/efeitos dos fármacos , Recompensa , Animais , Comportamento de Escolha/fisiologia , Esquema de Medicação , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Comportamento Alimentar/psicologia , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Motivação/fisiologia
13.
Artigo em Inglês | MEDLINE | ID: mdl-32292065

RESUMO

In rats, overnight fasting reduces the ability of systemic cholecystokinin-8 (CCK) to suppress food intake and to activate cFos in the caudal nucleus of the solitary tract (cNTS), specifically within glucagon-like peptide-1 (GLP-1) and noradrenergic (NA) neurons of the A2 cell group. Systemic CCK increases vagal sensory signaling to the cNTS, an effect that is amplified by leptin and reduced by ghrelin. Since fasting reduces plasma leptin and increases plasma ghrelin levels, we hypothesized that peripheral leptin administration and/or antagonism of ghrelin receptors in fasted rats would rescue the ability of CCK to activate GLP-1 neurons and a caudal subset of A2 neurons that coexpress prolactin-releasing peptide (PrRP). To test this, cFos expression was examined in ad libitum-fed and overnight food-deprived (DEP) rats after intraperitoneal CCK, after coadministration of leptin and CCK, or after intraperitoneal injection of a ghrelin receptor antagonist (GRA) before CCK. In fed rats, CCK activated cFos in ~60% of GLP-1 and PrRP neurons. Few or no GLP-1 or PrRP neurons expressed cFos in DEP rats treated with CCK alone, CCK combined with leptin, or GRA alone. However, GRA pretreatment increased the ability of CCK to activate GLP-1 and PrRP neurons and also enhanced the hypophagic effect of CCK in DEP rats. Considered together, these new findings suggest that reduced behavioral sensitivity to CCK in fasted rats is at least partially due to ghrelin-mediated suppression of hindbrain GLP-1 and PrRP neural responsiveness to CCK.


Assuntos
Regulação do Apetite/efeitos dos fármacos , Colecistocinina/administração & dosagem , Ingestão de Alimentos/efeitos dos fármacos , Jejum/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Grelina/sangue , Neurônios/efeitos dos fármacos , Rombencéfalo/efeitos dos fármacos , Animais , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Leptina/sangue , Masculino , Neurônios/metabolismo , Hormônio Liberador de Prolactina/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos Sprague-Dawley , Receptores de Grelina/metabolismo , Rombencéfalo/metabolismo , Transdução de Sinais
14.
Sci Rep ; 10(1): 4670, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170171

RESUMO

Solitary bees are frequently exposed to pesticides, which are considered as one of the main stress factors that may lead to population declines. A strong immune defence is vital for the fitness of bees. However, the immune system can be weakened by environmental factors that may render bees more vulnerable to parasites and pathogens. Here we demonstrate for the first time that field-realistic concentrations of the commonly used neonicotinoid insecticide thiacloprid can severely affect the immunocompetence of Osmia bicornis. In detail, males exposed to thiacloprid solutions of 200 and 555 µg/kg showed a reduction in hemocyte density. Moreover, functional aspects of the immune defence - the antimicrobial activity of the hemolymph - were impaired in males. In females, however, only a concentration of 555 µg/kg elicited similar immunosuppressive effects. Although males are smaller than females, they consumed more food solution. This leads to a 2.77 times higher exposure in males, probably explaining the different concentration thresholds observed between the sexes. In contrast to honeybees, dietary exposure to thiacloprid did not affect melanisation or wound healing in O. bicornis. Our results demonstrate that neonicotinoid insecticides can negatively affect the immunocompetence of O. bicornis, possibly leading to an impaired disease resistance capacity.


Assuntos
Abelhas/efeitos dos fármacos , Abelhas/imunologia , Imunossupressores/farmacologia , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Tiazinas/farmacologia , Animais , Biomarcadores , Contagem de Células , Comportamento Alimentar/efeitos dos fármacos , Feminino , Hemócitos/efeitos dos fármacos , Hemolinfa , Masculino
15.
Aquat Toxicol ; 222: 105447, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32145485

RESUMO

Multiple mechanisms for plastic consumption by marine animals have been proposed based on the feeding cues and behavior of the animal studied. We investigated plastic consumption in sea anemones. We found that anemones readily consumed pristine National Institute of Standards and Technology low-density polyethylene and high-density polyethylene II and III pre-production pellets. Anemone weight, crown area, and number of tentacles were measured before and after 12 days of daily pellet consumption. Crown area significantly increased for control anemones only. Fresh anemones were then sequentially fed consumed and egested pellets from two of the earlier daily trials to measure feeding retention time, which decreased over three to four feedings. The concentrations of elements in anemones (zinc, iron, arsenic, manganese, chromium, copper, vanadium, selenium, nickel, cadmium, and cobalt) were similar to control anemones that were not exposed to pellets. Lead concentrations were significantly higher in anemones fed HDPE III pellets as compared to control. Plastic consumption by marine animals might be reduced by reducing the amount of plastic that enters the ocean and understanding the chemical triggers underlying plastic consumption.


Assuntos
Monitoramento Biológico/métodos , Comportamento Alimentar/efeitos dos fármacos , Polietilenos/toxicidade , Anêmonas-do-Mar/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Metais/análise , Modelos Teóricos , Anêmonas-do-Mar/química , Anêmonas-do-Mar/crescimento & desenvolvimento , Oligoelementos/análise
16.
Aquat Toxicol ; 222: 105461, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32171118

RESUMO

Antibiotics may constitute a risk for aquatic detritivorous macroinvertebrates (i.e., shredders) via waterborne and dietary antibiotic exposure. In addition, antibiotics can alter the food quality for shredders mediated by shifts in leaf-associated decomposer (i.e., aquatic fungi and bacteria) communities. However, little is known about the relative importance of the waterborne and dietary effect pathway. Therefore, we followed a tiered testing approach aimed at assessing the relative importance of these effect pathways. We employed the antibiotic ciprofloxacin (CIP) and the shredder Gammarus fossarum as model stressor and test species, respectively. In a first step, we assessed the short-term waterborne toxicity of CIP using survival and leaf consumption of G. fossarum as response variables. Alterations in the leaf-associated decomposer community, which may be reflected by their palatability, were assessed using food choice assays. Finally, we conducted a 2 × 2-factorial experiment over 24 days assessing the pathways individually and combined using energy processing (i.e., leaf consumption and feces production), growth and energy storage (i.e., neutral lipid fatty acids) as variables. Short term waterborne exposure indicated low toxicity with LC50 and EC50 values of 13.6 and 6.4 mg CIP/L, respectively. At the same time, shredders did not prefer any leaf material during the food choice assay. However, the fungal community was significantly affected in the highest CIP-treatments (0.5 and 2.5 mg/L) suggesting an altered food quality for shredders. This assumption is supported by the results of the long-term assay. At 0.5 mg CIP/L, gammarids' leaf consumption, growth and energy storage were increased when subjected via the dietary pathway, which was linked to changes in the leaf-associated microbial community. Our data highlight the importance of dietary effect pathways for effects on shredders, potentially impacting energy dynamics in detritus-based stream ecosystems.


Assuntos
Anfípodes/efeitos dos fármacos , Antibacterianos/toxicidade , Ciprofloxacino/toxicidade , Comportamento Alimentar/efeitos dos fármacos , Folhas de Planta/metabolismo , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Antibacterianos/análise , Ciprofloxacino/análise , Dieta , Ecossistema , Microbiota/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/microbiologia , Rios/química
17.
Artigo em Inglês | MEDLINE | ID: mdl-32124147

RESUMO

Bumblebees exposed to neonicotinoid pesticides collect less pollen on foraging trips. Exposed bumblebees are also slower to learn to handle flowers, which may account for reduced pollen collection. It is unclear, however, why neonicotinoid exposure slows learning to handle flowers. We investigated the effect of imidacloprid, a neonicotinoid pesticide, on bumblebee motor learning using a lab model of flower handling. Bumblebees learned to invert inside a narrow tube and lift a petal-shaped barrier to reach a reward chamber. Imidacloprid-exposed bumblebees showed a dose-dependent delay to solve the task, which resulted from reduced switching between behavioural strategies and a subsequent delay in use of the successful strategy. This effect was consistent in colonies exposed at 10 but not 2.6 ppb, suggesting a variable effect on individuals at lower doses. These results help to explain why exposed bumblebees are slow to learn to handle flowers and collect less pollen on foraging trips.


Assuntos
Abelhas/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , Flores
18.
Artigo em Inglês | MEDLINE | ID: mdl-32208925

RESUMO

Phoenixin is a 20-amino acid peptide (PNX-20) cleaved from the small integral membrane protein 20 (SMIM20), with multiple biological roles in mammals. However, its role in nonmammalian vertebrates is poorly understood. This research aimed to determine whether PNX-20 influences feeding and metabolism in zebrafish. The mRNAs encoding SMIM20 and its putative receptor, super conserved receptor expressed in brain 3 (SREB3), are present in both central and peripheral tissues of zebrafish. Immunohistochemical analysis confirmed the presence of PNX-like immunoreactivity in the gut and in zebrafish liver (ZFL) cell line. We also found that short-term fasting (7 days) significantly decreased smim20 mRNA expression in the brain, gut, liver, gonads, and muscle, which suggests a role for PNX-20 in food intake regulation. Indeed, single intraperitoneal injection of 1,000 ng/g body wt PNX-20 reduced feeding in both male and female zebrafish, likely in part by enhancing hypothalamic cart and reducing hypothalamic/gut preproghrelin mRNAs. Furthermore, the present results demonstrated that PNX-20 modulates the expression of genes involved in glucose transport and metabolism in ZFL cells. In general terms, such PNX-induced modulation of gene expression was characterized by the upregulation of glycolytic genes and the downregulation of gluconeogenic genes. A kinetic study of the ATP production rate from both glycolytic and mitochondrial pathways demonstrated that PNX-20-treated ZFL cells exhibited significantly higher ATP production rate associated with glycolysis than control cells. This confirms a positive role for PNX-20 on glycolysis. Together, these results indicate that PNX-20 is an anorexigen with important metabolic roles in zebrafish.


Assuntos
Depressores do Apetite/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Proteínas de Homeodomínio/farmacologia , Fragmentos de Peptídeos/farmacologia , Proteínas de Peixe-Zebra/farmacologia , Peixe-Zebra/metabolismo , Animais , Regulação do Apetite/efeitos dos fármacos , Linhagem Celular , Feminino , Regulação da Expressão Gênica , Glicólise/genética , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Masculino , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Transdução de Sinais , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
19.
Trop Anim Health Prod ; 52(4): 2035-2041, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32016880

RESUMO

The principle of the study was to assess the influence of yeast-fermented cassava pulp (YFCP) as a protein supplement on feed intake, nutrient digestibilities, rumen microbial protein synthesis, fermentation end-products, and N-balance in Thai native beef cattle. The experiment was conducted following the 4 × 4 Latin square design using 4 levels of YFCP supplementation (0, 100, 200, and 300 g/head/day) in 3-year-old Thai native beef cattle crossbreds. The response of YFCP supplementation level using rice straw as a roughage source revealed promising results. The rumen ecology parameters including cellulolytic, amylolytic, and proteolytic bacterial population were significantly increased while the protozoal population were reduced, as affected by increasing level of YFCP supplementation (P < 0.05). In parallel with these results, totals VFA, propionate (C3) production in the rumen, and the ratio of C2:C3 were remarkably increased (P < 0.01), while rumen methane production by prediction from VFA was decreased (P < 0.01), as YFCP supplementation increased. Regarding, the nutrient digestibilities, those of OM and CP were remarkably enhanced (P < 0.01), hence increased DM intake. Furthermore, the use of YFCP at high level resulted in the highest N-balance and N retention absorption (P < 0.01). The results indicated that YFCP can be nutritionally enhanced by yeast fermentation, thus is promising to be used as a protein source in ruminant feeding.


Assuntos
Dieta/veterinária , Digestão/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Manihot/química , Nitrogênio/metabolismo , Nutrientes/fisiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Bovinos , Suplementos Nutricionais/análise , Digestão/fisiologia , Relação Dose-Resposta a Droga , Feminino , Fermentação , Alimentos e Bebidas Fermentados , Microbioma Gastrointestinal/fisiologia , Masculino , Rúmen/microbiologia , Saccharomyces cerevisiae/metabolismo , Soja
20.
PLoS One ; 15(2): e0224718, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32097407

RESUMO

BACKGROUND: Understanding the interactions between increased insecticide resistance and resting behaviour patterns of malaria mosquitoes is important for planning of adequate vector control. This study was designed to investigate the resting behavior, host preference and rates of Plasmodium falciparum infection in relation to insecticide resistance of malaria vectors in different ecologies of western Kenya. METHODS: Anopheles mosquito collections were carried out during the dry and rainy seasons in Kisian (lowland site) and Bungoma (highland site), both in western Kenya using pyrethrum spray catches (PSC), mechanical aspiration (Prokopack) for indoor collections, clay pots, pit shelter and Prokopack for outdoor collections. WHO tube bioassay was used to determine levels of phenotypic resistance of indoor and outdoor collected mosquitoes to deltamethrin. PCR-based molecular diagnostics were used for mosquito speciation, genotype for knockdown resistance mutations (1014S and 1014F) and to determine specific host blood meal origins. Enzyme-linked Immunosorbent Assay (ELISA) was used to determine mosquito sporozoite infections. RESULTS: Anopheles gambiae s.l. was the most predominant species (75%, n = 2706) followed by An. funestus s.l. (25%, n = 860). An. gambiae s.s hereafter (An. gambiae) accounted for 91% (95% CI: 89-93) and An. arabiensis 8% (95% CI: 6-9) in Bungoma, while in Kisian, An. arabiensis composition was 60% (95% CI: 55-66) and An. gambiae 39% (95% CI: 34-44). The resting densities of An. gambiae s.l and An. funestus were higher indoors than outdoor in both sites (An. gambiae s.l; F1, 655 = 41.928, p < 0.0001, An. funestus; F1, 655 = 36.555, p < 0.0001). The mortality rate for indoor and outdoor resting An. gambiae s.l F1 progeny was 37% (95% CI: 34-39) vs 67% (95% CI: 62-69) respectively in Bungoma. In Kisian, the mortality rate was 67% (95% CI: 61-73) vs 76% (95% CI: 71-80) respectively. The mortality rate for F1 progeny of An. funestus resting indoors in Bungoma was 32% (95% CI: 28-35). The 1014S mutation was only detected in indoor resitng An. arabiensis. Similarly, the 1014F mutation was present only in indoor resting An. gambiae. The sporozoite rates were highest in An. funestus followed by An. gambiae, and An. arabiensis resting indoors at 11% (34/311), 8% (47/618) and 4% (1/27) respectively in Bungoma. Overall, in Bungoma, the sporozoite rate for indoor resting mosquitoes was 9% (82/956) and 4% (8/190) for outdoors. In Kisian, the sporozoite rate was 1% (1/112) for indoor resting An. gambiae. None of the outdoor collected mosquitoes in Kisian tested positive for sporozoite infections (n = 73). CONCLUSION: The study reports high indoor resting densities of An. gambiae and An. funestus, insecticide resistance, and persistence of malaria transmission indoors regardless of the use of long-lasting insecticidal nets (LLINs). These findings underline the difficulties of controlling malaria vectors resting and biting indoors using the current interventions. Supplemental vector control tools and implementation of sustainable insecticide resistance management strategies are needed in western Kenya.


Assuntos
Anopheles/genética , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Plasmodium falciparum/imunologia , Descanso/fisiologia , Animais , Anopheles/classificação , Anopheles/parasitologia , Ensaio de Imunoadsorção Enzimática , Comportamento Alimentar/efeitos dos fármacos , Feminino , Genótipo , Comportamento de Busca por Hospedeiro/efeitos dos fármacos , Resistência a Inseticidas/genética , Mosquiteiros Tratados com Inseticida , Inseticidas/farmacologia , Quênia/epidemiologia , Malária Falciparum/transmissão , Nitrilos/farmacologia , Reação em Cadeia da Polimerase , Piretrinas/farmacologia , Esporozoítos/imunologia
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