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1.
Bratisl Lek Listy ; 120(12): 881-886, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31855045

RESUMO

BACKGROUND: Galangin, a flavonoid compound with acetylcholinesterase inhibitory activity, may improve cognitive functions by enhancing cholinergic transmission. OBJECTIVES: We aimed to investigate the effects of galangin on spatial memory impairment in rats. METHODS: The effects of galangin (50 and 100 mg/kg) and reference anti-dementia drug donepezil (1mg/kg) administrations were examined on memory impairment induced by the muscarinic cholinergic receptor antagonist scopolamine or the nicotinic cholinergic receptor antagonist mecamylamine in the Morris water maze (MWM) test. Hippocampal acetylcholine concentrations were also determined. RESULTS: Galangin 50 and 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in scopolamine-treated rats. Galangin 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in mecamylamine-treated rats. The effects of galangin in the MWM were comparable with donepezil. Scopolamine and mecamylamine decreased acetylcholine concentrations, whereas galangin both alone and with mecamylamine or scopolamine administration increased acetylcholine concentrations. CONCLUSION: Galangin improved memory impairment comparable to donepezil and nicotinic and muscarinic receptors may be involved in this effect. Galangin may be considered as a promising flavonoid in the prevention and treatment of memory impairment in Alzheimer's disease and other dementias (Fig. 7,Ref. 37).


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Flavonoides/farmacologia , Aprendizagem em Labirinto/efeitos dos fármacos , Mecamilamina/toxicidade , Escopolamina/toxicidade , Memória Espacial/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/fisiologia , Inibidores da Colinesterase , Donepezila , Flavonoides/administração & dosagem , Aprendizagem em Labirinto/fisiologia , Mecamilamina/efeitos adversos , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Escopolamina/efeitos adversos
2.
J Chem Ecol ; 45(10): 838-848, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31677136

RESUMO

Many aquatic organisms detect and avoid damage-released cues from conspecifics, but the chemical basis of such responses, and the effects of prolonged exposure to such cues, remain poorly understood. Injured tadpoles of the cane toad (Rhinella marina) produce chemical cues that induce avoidance by conspecific tadpoles; and chronic exposure to those cues decreases rates of tadpole survival and growth, and reduces body size at metamorphosis. Such effects suggest that we might be able to use the cane toads' alarm cue for biocontrol of invasive populations in Australia. In the present study, we examined behavioral and ecological effects of compounds that are present in cane toad tadpoles and thus, might trigger avoidance of crushed conspecifics. Four chemicals (L-Arg, L-Leu-L-Leu-OH, L-Leu-L-Ile-OH and suberic acid) induced behavioral avoidance in toad tadpoles at some (but not all) dosage levels, so we then exposed toad larvae to these chemicals over the entire period of larval development. Larval survival and size at metamorphosis were decreased by chronic exposure to crushed conspecifics (consistent with earlier studies), but not by exposure to any of the four chemicals. Indeed, L-Arg increased body size at metamorphosis. We conclude that the behavioral response to crushed conspecifics by cane toad tadpoles can be elicited by a variety of chemical cues, but that consistent exposure to these individual chemical cues does not affect tadpole viability or developmental trajectory. The optimal behavioral tactic of a tadpole may be to flee if it encounters even a single chemical cue likely to have come from an injured conspecific (indicative of predation risk), whereas the continuing presence of that single chemical (but no others) provides a less reliable signal of predation risk. Our data are consistent with results from studies on fish, that suggest a role for multiple chemicals in initiating alarm responses to damage-released cues.


Assuntos
Arginina/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Bufo marinus/fisiologia , Caprilatos/farmacologia , Ácidos Dicarboxílicos/farmacologia , Oligopeptídeos/farmacologia , Animais , Tamanho Corporal/efeitos dos fármacos , Bufo marinus/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/efeitos dos fármacos , Oligopeptídeos/química
3.
Bull Environ Contam Toxicol ; 103(6): 776-782, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31686122

RESUMO

Earthworms exhibit clumping behaviour in and out of the soil. However, it remains unknown if such social behaviour ultimately influences the outcome of ecotoxicological experiments in the laboratory. We performed several overnight avoidance tests to determine whether social behaviour (i.e., local enhancement) is a factor in pollution avoidance behaviour in the earthworm Eisenia fetida. The results showed that there was no clear influence of social behaviour on the choice or avoidance of Cd contaminated soils, although we suspect that 50 mg Cd/kg might not have been high enough to elicit a significant avoidance response. Nevertheless, when offered a choice between clean undisturbed soil and previously inhabited soil, the worms preferred the previously inhabited soil (p < 0.01). While the level of metal pollution investigated in this study did not disrupt or help predict social dynamics, local enhancement, perhaps driven by some sort of habitat imprinting, was successfully documented in Eisenia fetida.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Cádmio/toxicidade , Oligoquetos/efeitos dos fármacos , Comportamento Social , Poluentes do Solo/toxicidade , Solo/química , Animais , Bioensaio , Cádmio/análise , Ecossistema , Modelos Teóricos , Oligoquetos/fisiologia , Poluentes do Solo/análise , Testes de Toxicidade
4.
J Toxicol Sci ; 44(10): 681-691, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31588059

RESUMO

Zinc (Zn) is an essential element, but excess amounts are known to cause neurotoxic effects. The risk of excessive Zn intake is increased by supplementing food intake with dietary supplements. Ageing affects many cellular processes that predispose individuals to neurodegeneration. Indeed, the prevalence of senile dementia such as Alzheimer's disease, Parkinson's disease, and vascular-type dementia increases with age. As such, we investigated the effects of long-term exposure to excess Zn on learning and memory in aged mice. ICR-JCL female mice (aged 26 weeks) were administered 0, 200, or 500 ppm Zn as zinc chloride in drinking water for 30 weeks. After 30-week administration, aged female animals were subjected to Y-maze, novel object recognition, and step-through passive avoidance tests. Chronic exposure to Zn did not inhibit learning and memory in the Y-maze test, but dose-dependently inhibited learning and memory in novel object recognition and step-through passive avoidance tests. These results indicate the potential for chronic Zn exposure to dose-dependently inhibit both long-term and novel object recognition memory. Results of microarray analysis revealed significant changes in gene expression of transthyretin and many olfactory receptors in the hippocampus of Zn-treated mice.


Assuntos
Cloretos/toxicidade , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Síndromes Neurotóxicas , Compostos de Zinco/toxicidade , Envelhecimento , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Síndromes Neurotóxicas/genética , Transcriptoma/efeitos dos fármacos
5.
Ecotoxicol Environ Saf ; 186: 109757, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606638

RESUMO

Contamination seems to exert a crucial role in the spatial distribution of some organisms, such as shrimps and fish. Both, especially the freshwater fish Danio rerio and the shrimp Atyaephyra desmarestii, have been tested experimentally for their avoidance response and have showed the ability to escape from toxic effects. As the behavior of avoiding or not the contamination might be altered in the presence of other factors, the aim of the current study was to verify whether the avoidance response of both species, when exposed jointly (multispecies tests), to a copper gradient is different from the avoidance response observed in monospecies tests. The avoidance was assessed in a multi-compartmented exposure system, in which a copper gradient was simulated. Organisms were tested individually and together. Both species avoided potentially toxic copper concentrations; however, shrimps were slightly more sensitive in the monospecies tests: AC50 (avoidance concentration for 50% of the population) of 60 (53-68) µg/L for the zebrafish and 50 (45-56) µg/L for the shrimp. In the multispecies tests, the sensitivity pattern changed: the avoidance response by the fish [AC50: 30 (14-46) µg/L] was greater than by the shrimps [AC50: 70 (22-141) µg/L]. Although the AC50 values are in the same order of magnitude, a slight trend to change the avoidance pattern was observed in the shrimps during multispecies test: the avoidance was lower and time-delayed. This behavioral change could be linked to the stress caused by the zebrafish sharing the space with the shrimps, perhaps increasing the territorialism of the fish, or a delay in the shrimps detecting the risk of contamination.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Relação Dose-Resposta a Droga , Água Doce/química , Especificidade da Espécie
6.
Aquat Toxicol ; 216: 105312, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31563086

RESUMO

Many coastal systems have been experiencing the effects of non-chemical and chemical anthropological stressors through respective increases in surface water temperatures and rainstorm-derived runoff events of pyrethroid pesticide movement into waterways such as the San Francisco Bay-Delta. Salmonid populations in the Bay-Delta have been dramatically declining in recent decades. Therefore, the aim of this study was to investigate the interactive effects of bifenthrin, a pyrethroid insecticide, and increasing water temperatures on targeted neuroendocrine and behavioral responses in Chinook salmon (Oncorhynchus tshawytscha) parr (10- month post-hatch). Parr were reared at 11 °C, 16.4 °C, or 19 °C for 14 days and, in the final 96 h of rearing, exposed to nominal concentrations of 0, 0.15, or 1.5 µg/L bifenthrin. A predatory avoidance Y-Maze behavioral assay was conducted immediately following exposures. Parr were presented a choice of clean or odorant zones, and locomotive behavior was recorded. Thyroid hormones (T3 and T4), estradiol, and testosterone were quantified within plasma using ELISAs, and the expression of brain hormone and dopamine receptor genes were also evaluated by qPCR. Brain dopamine levels were analyzed by LC/MS. No significant changes were observed in brain transcripts or plasma hormone concentrations with bifenthrin or increasing temperature. However, temperature did significantly lower brain dopamine levels in fish reared at 19 °C compared to 11 °C controls, but was unaltered by bifenthrin treatment. In contrast, parr reared at 11 °C and exposed to 1.5 µg/L bifenthrin spent significantly less time avoiding a predatory odorant compared to vehicle controls reared at 11 °C. The 16.4 °C and 1.5 µg/L-treated fish spent significantly more time in the neutral arm compared to the odorant and clean arms, as well as spending significantly less time in the clean arm compared to the 11 °C control fish. These results suggest that the interaction of temperature and bifenthrin may be adversely impacting predator-avoidance behavior, which may not be related to dopaminergic responses.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Piretrinas/toxicidade , Salmão/fisiologia , Temperatura Ambiente , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Dopamina/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hormônios/metabolismo , Poluentes Químicos da Água/toxicidade
7.
Int J Neurosci ; 129(12): 1203-1212, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31393204

RESUMO

Purpose of the study: Kaempferol (KM) is a flavonoid found in plant-derived foods and medicinal plants. Recently, it is well established that KM plays a protective role to develop Alzheimer's disease. The current study aimed at evaluating the effect of intracerebroventricular micro-injection of KM on memory retention of passive avoidance learning (MRPAM) and identifying the potentially related cholinergic mechanisms (ChMs) in rats. Materials and methods: In the current study, male Wistar rats randomly divided into control, vehicle and KM (10, 20 and 40 µg/rat) groups. Moreover, MRPAM was evaluated by shuttle box test. The role of ChM was studied using non-selective and selective acetylcholine antagonists (scopolamine [SCN], 4-DAMP and methoctramine [MN], respectively) as well as pirenzepine (PZ) in combination with KM. Results: The employment of KM (40 µg/rat) improved the SCN-induced memory impairment in MRPAM. Co-treatment with KM (40 µg/rat) plus 4-DAMP significantly increased the step-through latency (STL, P < 0.05; 167 ± 28 s) and decreased the total dark chamber (TDC, P < 0.05; 121 ± 31 s) compared with those of the 4-DAMP group (STL: 75 ± 13 s; TDC: 178 ± 46 s). Co-treatment with KM (40 µg/rat) plus PZ attenuated STL, and also increased TDC (P < 0.01; 220 ± 28 s) compared with those of the PZ group. Co-treatment with KM (10 and 20 µg/rat) and MN increased STL (P < 0.05), and deceased TDC compared with those of the MN group (P < 0.01). Conclusions: Totally, the results of the present study showed that cholinergic system may be involved in improving effect of KM on SCN-induced memory impairment.


Assuntos
Acetilcolina/fisiologia , Aprendizagem da Esquiva/efeitos dos fármacos , Antagonistas Colinérgicos/administração & dosagem , Quempferóis/administração & dosagem , Memória/efeitos dos fármacos , Antagonistas Muscarínicos/administração & dosagem , Animais , Aprendizagem da Esquiva/fisiologia , Diaminas/administração & dosagem , Injeções Intraventriculares , Masculino , Memória/fisiologia , Microinjeções , Piperidinas/administração & dosagem , Pirenzepina/administração & dosagem , Ratos Wistar , Escopolamina/administração & dosagem
8.
Toxicol Lett ; 315: 96-106, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31386889

RESUMO

We investigate the long-term effect of very-low dose exposure to a mixture of six pesticides associated with hydrophilic vitamin deficiency on the neurobehavioral outcomes of rats. Two hundred Wistar rats were divided into four groups, two control groups, a vitamin sufficient control group and a vitamin deficiency control group and 2 test groups, a vitamin sufficient test group, and a vitamin deficiency group. The test groups were exposed for 9 months to a mixture of diquat, imazamox, imazethapyr, tepraloxydin, bentazone and acifluorfen in doses of 0.01xNOAEL (mg/kg bw/day). After 9 months of exposure, the behavior changes were evaluated by open field test and elevated plus maze test and the memory was assessed by passive avoidance test. Chronic vitamin deficiency decreased locomotor and special orientation activity and increased anxiety-like behavior in rats. Exposure to very low doses of a mixture of 6 pesticides caused central nervous effects, manifested as decreased locomotor activity, and increased anxiety levels. Vitamin deficiency and low dose chronic pesticides mixture exposure thus affected the central nervous system, especially long-term memory.


Assuntos
Deficiência de Vitaminas/complicações , Deficiência de Vitaminas/fisiopatologia , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Doenças do Sistema Nervoso/induzido quimicamente , Doenças do Sistema Nervoso/fisiopatologia , Praguicidas/toxicidade , Animais , Modelos Animais de Doenças , Masculino , Ratos , Ratos Wistar
9.
Rev Environ Health ; 34(3): 303-307, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31444967

RESUMO

The aim of this research was to assess the effect of soil contamination with titanium (Ti) and iron (Fe) at military sites in Ukraine using the avoidance and reproduction tests with Folsomia candida (springtail). The soil used for the tests was sampled in 2017 from Dolyna, Ivano-Frankivsk region, Ukraine from two plots, namely a contaminated and a control site. The sample site is a former military site previously used for tank training. At the control site mainly the concentrations of Ti and Fe were exceeded. The control soil was free from contamination. The avoidance test and reproduction test were conducted with the use of springtail species F. candida. The following nine levels of contamination with heavy metals were established: 1%, 1.5%, 5%, 10%, 15%, 25%, 50%, 75% and 100%. The duration of the avoidance test was 7 days, and that of the reproduction test was 28 days. Overall, the results show that the avoidance and reproduction tests with collembolans have the potential to be used as screening tools in an ecological risk assessment of heavy metals. In the avoidance test, the concentrations from 1.5 to 100% significantly decreased the number of F. candida in the contamination site in comparison to the control site. At the same time, avoidance was not observed in the first concentration (1%). According to the reproduction test, the negative effect on the number of F. candida juveniles was observed beginning at the 10% dose. The half maximal effective concentration (EC50) for the avoidance test was 50.12%, while that for the reproduction test was 22.39%. The contamination with heavy metals at the military areas indicated the short- and long-term toxicity risk on the springtail F. candida.


Assuntos
Artrópodes/efeitos dos fármacos , Ferro/toxicidade , Poluentes do Solo/toxicidade , Titânio/toxicidade , Testes de Toxicidade , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Militares , Reprodução/efeitos dos fármacos , Medição de Risco
10.
Pharmacol Biochem Behav ; 185: 172762, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31445057

RESUMO

RATIONALE: The majority of synthetic cathinone research has used only male subjects, and as a result there are few studies assessing the impact of biological sex on their effects. OBJECTIVES: The current work extends the characterization of the second-generation synthetic cathinone, α-PVP, by investigating how biological sex impacts α-PVP's aversive and rewarding effects important to its use and potential abuse. METHODS: A combined conditioned taste avoidance/conditioned place preference preparation was utilized in which adult male and female Sprague Dawley rats were injected with 1.5, 3 or 6 mg/kg of racemic α-PVP or vehicle (saline) (IP). Following a 24-day washout period, rats were then tested for thermoregulatory effects of α-PVP using subcutaneous microchips to measure body temperature changes over the course of 8 h. This was followed 21 days later by assessments for α-PVP-induced locomotor activity and stereotypies over a 1-h session. RESULTS: Dose-dependent conditioned taste avoidance was evident in both males and females, although females displayed weaker avoidance at 3 mg/kg compared to males. Males displayed a dose-dependent conditioned place preference, while females did not form a place preference at any dose. α-PVP elicited dose- and time-dependent hyperthermia, with males displaying a faster on-set and delayed off-set compared to females. α-PVP also produced dose- and time-dependent increases in locomotor activity (F > M) and stereotypies (M > F). CONCLUSIONS: As described, males displayed greater rewarding (as indexed by place preference conditioning) and aversive (as indexed by taste avoidance, hyperthermia and stereotypies) effects of α-PVP. Although comparisons between males and females in α-PVP self-administration have not been reported, these data suggest that males may be more likely to use the drug. The implications for sex differences in human use of α-PVP were discussed.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/farmacologia , Febre/induzido quimicamente , Locomoção/efeitos dos fármacos , Pentanonas/farmacologia , Pirrolidinas/farmacologia , Paladar/efeitos dos fármacos , Animais , Temperatura Corporal/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/administração & dosagem , Condicionamento Clássico , Relação Dose-Resposta a Droga , Feminino , Masculino , Atividade Motora/efeitos dos fármacos , Pentanonas/administração & dosagem , Pirrolidinas/administração & dosagem , Ratos , Ratos Sprague-Dawley , Recompensa , Fatores Sexuais
11.
Zebrafish ; 16(5): 443-450, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31436486

RESUMO

The two-factor theory predicts that the acquisition of avoidance responses is dependent on fear reduction; as such, drugs that reduce or increase fear or anxiety states should alter inhibitory avoidance (IA) acquisition. The present experiment used white spaces as aversive unconditioned stimuli in IA in zebrafish. Adult zebrafishes were tested in three experiments: validation of white compartment as aversive in IA; open field test; and effect of antidepressant (fluoxetine, imipramine) and anxiolytic (diazepam, clonazepam). The data show the effectiveness of the white compartment as an aversive stimulus in IA. Antidepressant fluoxetine did not alter and imipramine impairs avoidance acquisition in higher doses. Imipramine also produced a sedative effect in lower doses. Anxiolytic and stimulant drugs facilitated learning at doses which did not impair locomotion, suggesting that pharmacological manipulation of other factors in addition to fear/anxiety can impact aversive learning in zebrafish.


Assuntos
Antidepressivos Tricíclicos/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Fluoxetina/farmacologia , Imipramina/farmacologia , Inibidores de Captação de Serotonina/farmacologia , Animais , Antidepressivos Tricíclicos/administração & dosagem , Feminino , Fluoxetina/administração & dosagem , Imipramina/administração & dosagem , Masculino , Aprendizagem em Labirinto , Inibidores de Captação de Serotonina/administração & dosagem , Peixe-Zebra/fisiologia
12.
Eur J Pharmacol ; 859: 172530, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31283934

RESUMO

Cinnamon, a spice widely used in cuisine, has been reported to exert therapeutic effects. Recently, cinnamon was shown to improve memory in some animal models of memory impairment and in poor learning mice. This study aimed to investigate the effect of cinnamaldehyde, the major compound in cinnamon on passive avoidance memory and activation of hippocampal Akt (protein kinase B), ERK (extracellular signal-regulated kinase) and GSK-3ß (Glycogen Synthase Kinase-3beta) in mice. In the present study, oral cinnamaldehyde at doses of 12.5, 25, 30, 40, 45, 50 and 100 mg/kg/daily was administered to adult male NMRI mice, initiated 10 days before training and continued during training and retention days. Training of passive avoidance task was performed on day 10 and a retention trial was done 24 h after. Upon completion of the retention test, hippocampi were removed for Western blot analysis to detect the phosphorylated and total levels of Akt, ERK and GSK-3ß proteins. Results showed that cinnamaldehyde exerts a biphasic effect on passive avoidance memory by impairing memory at lower doses while improving at higher doses. Moreover, at memory improving doses, cinnamaldehyde increased the phosphorylated forms of hippocampal Akt, ERK and GSK-3ß while these proteins did not change at impairing doses of cinnamaldehyde. For the first time, this study revealed a biphasic effect of cinnamaldehyde on memory as well as indicating that the memory improving effect of higher doses of this substance is accompanied with hippocampal Akt, ERK and GSK-3ß signaling alterations in adult mice.


Assuntos
Acroleína/análogos & derivados , Aprendizagem da Esquiva/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/efeitos dos fármacos , Memória/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Acroleína/farmacologia , Animais , Relação Dose-Resposta a Droga , Hipocampo/metabolismo , Hipocampo/fisiologia , Masculino , Camundongos , Fosforilação/efeitos dos fármacos
13.
Ecotoxicol Environ Saf ; 182: 109446, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31323523

RESUMO

Increased use of sugarcane pesticides and their destination to non-target environments in Brazil has generated concerns related to the conservation of more vulnerable groups, such as amphibians. Besides the high skin permeability, tadpoles are constantly restricted to small and ephemeral ponds, where exposure to high concentrations of pesticides in agricultural areas is inevitable. This study evaluated chronic effects caused by sub-lethal concentrations of 2,4-dichlorophenoxyacetic acid herbicide on energy storage, development, respiration rates, swimming performance and avoidance behavior of bullfrog tadpoles (Lithobates catesbeianus). Firstly, we conducted acute toxicity test (96 h) to estipulate sub-lethal concentrations of 2,4-D and evaluate the sensitivity of three tadpoles' species to this herbicide. Results showed that Leptodactylus fuscus presented the lowest LC50 96 h, 28.81 mg/L, followed by Physalaemus nattereri (143.08 mg/L) and L. catesbeianus (574.52 mg/L). Chronic exposure to 2,4-D (125, 250 and 500 µg/L) delayed metamorphosis and inhibited the growth of tadpoles at concentrations of 125 µg/L. Effects on biochemical reserves showed that 2,4-D increased total hepatic lipids in tadpoles, although some individual lipid classes (e.g. free fatty acids and triglycerides) were reduced. Protein and carbohydrates contents were also impaired by 2,4-D, suggesting a disruption on energy metabolism of amphibians by the herbicide. In addition to biochemical changes, respiration rates and swimming speed were also decreased after chronic exposure to 2,4-D, and these responses appeared to be correlated with the changes detected in the basic energy content. Avoidance test indicated that tadpoles of L. catesbeinus avoided the presence of 2,4-D, however they were unable to detect increasing gradients of the contaminant. Our data showed that chronic exposure to 2,4-D impaired biochemical, physiological and behavioral aspects of tadpoles, which may compromise their health and make them more vulnerable to environmental stressors in natural systems.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Aprendizagem da Esquiva/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Herbicidas/toxicidade , Larva/efeitos dos fármacos , Taxa Respiratória/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Brasil , Relação Dose-Resposta a Droga , Larva/metabolismo , Metamorfose Biológica/efeitos dos fármacos , Rana catesbeiana , Natação , Testes de Toxicidade Aguda
14.
Folia Med (Plovdiv) ; 61(2): 258-265, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31301661

RESUMO

BACKGROUND: Parkinson's disease (PD) is the second most common neurode-generative disease, usually detected by its motor symptoms. The non-motor symptoms, including cognitive deficits, have been of great interest to researchers in the last few decades. AIM: To assess the effect of pramipexole on learning and memory in naïve and haloperidol-challenged rats. MATERIALS AND METHODS: Male Wistar rats divided into 9 groups (n=8): naïve - saline, pramipexole 0.5; 1 and 3 mg/kg bw; Haloperidol groups - saline, haloperidol, haloperidol + pramipexole 0.5; 1 and 3 mg/kg bw. Two-way active avoidance test (TWAA) and activity cage were performed. The studied parameters were: number of conditioned and unconditioned responses, vertical and horizontal movements. Statistical analysis was done using SPSS 19. RESULTS: The naïve experimental groups significantly increased the number of conditioned responses during the tests for short- and long-term memory, compared with the saline groups (p<0.05). During the short-memory test only the animals with the lowest dose of PMX significantly increased the number of unconditioned responses whereas during the long-term memory test all experimental groups increased the number of escapes in comparison with the saline groups (p<0.05). Challenge dose of haloperidol attenuates learning and memory in pramipexol treated rats. Only the highest dose of pramipexol showed significant increase in conditioned and unconditioned responses compared with the haloperidol group (p<0.05). CONCLUSION: Pramipexole improves learning and memory in naïve rats by enhancing dopaminergic neurotransmission. This is probably not the only mechanism involved. This is confirmed by the decrease in learning and memory ability in rats with haloperidol-challenge.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Agonistas de Dopamina/farmacologia , Memória/efeitos dos fármacos , Pramipexol/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Antagonistas de Dopamina/farmacologia , Haloperidol/farmacologia , Aprendizagem/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar
15.
Sci Total Environ ; 692: 519-528, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31351294

RESUMO

Environmental estrogens from anthropogenic activities are ubiquitous in aquatic ecosystems. Ambient temperature in these systems also fluctuates in daily, seasonal, and long-term rhythms. While both factors have been studied extensively, their interaction on aquatic life is critical to understand. The objective of this study was, therefore, to examine how behavior and gene expression are impacted by estrogenic exposure across a range of environmental temperatures. Larval fathead minnows (Pimephales promelas) were exposed to estrone (E1) at two concentrations (nominal 625 and 1250 ng/L) or to an ethanol solvent control, at one of four temperatures (15, 18, 21 and 24 °C) from fertilization to 21 days post-hatch. Exposed larvae were assessed for alterations in predator evasion performance and mRNA abundances of two genes for calcium channel receptors found in muscles - dihydropyridine receptor (dhpr) and ryanodine receptor 1, and the gonadal genes anti-Müllerian hormone, cytochrome P450 gonadal aromatase (cyp19a), doublesex and mab-3 related transcription factor 1 (dmrt1) and estrogen receptor 1 (esr1). Larval escape angle, escape latency, as well as systemic esr1 and cyp19a mRNA abundances were altered by an interaction between E1 concentration and temperature. E1-exposed larval exhibited reduced escape performance across all tested temperatures, whereas decreased systemic dhpr mRNA abundance was observed only at 18 °C. E1-exposure reduced systemic mRNA abundances of amh, cyp19a, dhpr, and ryr1, while temperature significantly reduced systemic cyp19a and dhpr mRNA abundances. E1-exposure and temperature significant enhanced systemic mRNA abundances of esr1 and cyp19a, respectively. These complex results illustrate the importance of considering how abiotic factors may moderate the effects of contaminant exposure during the sensitive larval developmental stage, as temperature modulates effects of estrogenic exposure on animal performance and mRNA abundances.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Cyprinidae/fisiologia , Exposição Ambiental/efeitos adversos , Estrona/efeitos adversos , RNA Mensageiro/metabolismo , Poluentes Químicos da Água/análise , Animais , Feminino , Proteínas de Peixes/metabolismo , Masculino , Comportamento Predatório , Temperatura Ambiente
16.
Behav Processes ; 166: 103905, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31310793

RESUMO

Globally, native predators and scavengers are threatened through the incidence of illegal poisoning due to increasing human-wildlife conflicts. The use of conditioned taste aversion (CTA) may mitigate such conflicts. CTA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CTA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five (thiabendazole, thiram, levamisole, fluconazole and fluralaner) were finally selected to be tested in CTA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CTA effect. Thiabendazole, thiram and levamisole can therefore induce CTA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is an undetectable, relatively safe and accessible compound that can induce CTA in canids, and opens new possibilities to develop methods of non-lethal predation control.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Paladar , Animais , Animais Selvagens , Condicionamento Clássico/efeitos dos fármacos , Cães , Fluconazol/farmacologia , Isoxazóis/farmacologia , Levamisol/farmacologia , Masculino , Tiabendazol/farmacologia , Tiram/farmacologia
17.
Int J Toxicol ; 38(5): 405-414, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31220985

RESUMO

Exposure to fluoride (F) during the development affects central nervous system of the offspring rats which results in the impairment of cognitive functions. However, the exact mechanisms of F neurotoxicity are not clearly defined. To investigate the effects of perinatal F exposure on memory ability of young rat offspring, dams were exposed to 5 and 10 mg/L F during gestation and lactation. Additionally, we evaluated the possible underlying neurotoxic mechanisms implicated. The results showed that the memory ability declined in 45-day-old offspring, together with a decrease of catalase and glutamate transaminases activity in specific brain areas. The present study reveals that exposure to F in early stages of rat development leads to impairment of memory in young offspring, highlighting the alterations of oxidative stress markers as well as the activity of enzymes involved in the glutamatergic system as a possible mechanisms of neurotoxicity.


Assuntos
Encéfalo/efeitos dos fármacos , Fluoretos/toxicidade , Troca Materno-Fetal , Memória/efeitos dos fármacos , Alquil e Aril Transferases/metabolismo , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Catalase/metabolismo , Feminino , Ácido Glutâmico/metabolismo , Glutationa Peroxidase/metabolismo , Masculino , Malondialdeído/metabolismo , Gravidez , Ratos Wistar , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismo
18.
Int J Neurosci ; 129(11): 1053-1065, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31215291

RESUMO

Aim: Alzheimer's disease (AD) is characterized by oxidative stress, neuroinflammation and progressive cognitive decline. Abscisic acid (ABA) is produced in a variety of mammalian tissues, including brain. It has anti-inflammatory and antioxidant effects and elicits a positive effect on spatial learning and memory performance. Here, the possible protective effect of ABA was evaluated in streptozotocin (STZ)-induced AD rat model which were injected intracerebroventriculary (i.c.v.) with STZ (3 mg/kg). Material and Methods: The STZ-treated animals received ABA (10 µg/rat, i.c.v.), ABA plus PPARß/δ receptor antagonist (GSK0660, 80 nM/rat) or ABA plus selective inhibitor of PKA (KT5720, 0.5 µg/rat) for 14 d. Learning and memory were determined using Morris water maze (MWM) and passive avoidance (PA) tests. Results: The data showed that STZ produced a significant learning and memory deficit in both MWM and PA tests. ABA significantly prevented the learning and memory impairment in STZ-treated rats. However, ABA effects were blocked by GSK0660 and KT5720. Conclusion: The data indicated that ABA attenuates STZ-induced learning and memory impairment and PPAR-ß/δ receptors and PKA signaling are involved, at least in part, in the ABA mechanism.


Assuntos
Ácido Abscísico/farmacologia , Doença de Alzheimer/tratamento farmacológico , Peptídeos e Proteínas de Sinalização Intracelular/farmacologia , Aprendizagem/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , PPAR delta/antagonistas & inibidores , PPAR beta/antagonistas & inibidores , Reguladores de Crescimento de Planta/farmacologia , Ácido Abscísico/administração & dosagem , Doença de Alzheimer/induzido quimicamente , Animais , Antibióticos Antineoplásicos/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Carbazóis/farmacologia , Modelos Animais de Doenças , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Fármacos Neuroprotetores/administração & dosagem , Pirróis/farmacologia , Ratos , Ratos Wistar , Estreptozocina/farmacologia , Sulfonas/farmacologia , Tiofenos/farmacologia
19.
PLoS One ; 14(6): e0217458, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31216290

RESUMO

Rats not only avoid ingesting a substance associated with LiCl toxicosis, but they display rejection reflexes (e.g., gapes) to its taste; this latter response is thought to reflect disgust or taste aversion. Prior work has shown that rats also avoid consuming foods/fluids associated with other adverse gastrointestinal (GI) effects like lactose indigestion but without the concomitant change in oromotor responses (taste reactivity; TR) indicative of aversion. Because of interpretive limitations of the methods used in those studies, we revisited the taste aversion-avoidance distinction with a design that minimized non-treatment differences among groups. Effects on intake and preference (Experiments 1a, 1b, and 2), as well as consummatory (TR, Experiment 1a and 1b) and appetitive (Progressive Ratio, Experiment 2) behaviors to the taste stimulus were assessed after training. In both experiments, rats were trained to associate 0.2% saccharin (CS) with intraduodenal infusions of LiCl, Lactose, or NaCl control. Rats trained with 18% lactose, 0.3 and 1.5 mEq/kg dose of LiCl subsequently avoided the taste CS in post-training single-bottle intake tests and two-bottle choice tests. However, only those trained with 1.5 mEq/kg LiCl displayed post-conditioning increases in taste CS-elicited aversive TR (Experiment 1a and 1b). This dose of LiCl also led to reductions in breakpoint for saccharin. The fact that conditioned avoidance is not always accompanied by changes in other common appetitive and/or consummatory indices of ingestive motivation further supports a functional dissociation between these processes, and highlights the intricacies of visceral influences on taste-guided ingestive motivation.


Assuntos
Aprendizagem da Esquiva/fisiologia , Modelos Biológicos , Percepção Gustatória/fisiologia , Paladar/fisiologia , Animais , Agentes Aversivos/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Cloreto de Lítio/farmacologia , Masculino , Ratos , Ratos Sprague-Dawley , Sacarina/farmacologia , Percepção Gustatória/efeitos dos fármacos
20.
Behav Processes ; 165: 1-3, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31185264

RESUMO

The nematode Phasmarhabditis hermaphrodita can infect and kill many species of slugs and has been formulated into a biological control agent for farmers and gardeners. P. hermaphrodita can manipulate the behaviour of slugs, making those infected move to areas where the nematode is present. Research suggests P. hermaphrodita uses manipulation of biogenic amines to achieve this, however the exact role of serotonin and dopamine needs further elucidation. Here we fed slugs Deroceras invadens (uninfected and infected with P. hermaphrodita) apomorphine, sertraline and haloperidol and observed their behaviour when given a choice between a P. hermaphrodita infested habitat, or a parasite free area of soil. In contrast to their usual P. hermaphrodita avoidance behaviour, uninfected D. invadens fed sertraline were attracted to the nematodes and conversely those fed haloperidol avoided the nematodes. D. invadens fed apomorphine were recorded equally on the control and nematode side. D. invadens pre-infected with P. hermaphrodita fed sertraline and apomorphine were found significantly more on the side with the nematodes. However, suppressing dopaminergic signalling through feeding with haloperidol abrogated this attraction and slugs were found on both sides. These results demonstrate that serotonin and dopamine are potential regulators of behavioural manipulation by P. hermaphrodita.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Agentes de Controle Biológico/farmacologia , Gastrópodes/efeitos dos fármacos , Gastrópodes/parasitologia , Rhabditoidea , Animais , Apomorfina/farmacologia , Aprendizagem da Esquiva/fisiologia , Dopamina/fisiologia , Haloperidol/farmacologia , Serotonina/fisiologia , Sertralina/farmacologia , Solo/parasitologia
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