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1.
PeerJ ; 5: e3739, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28890851

RESUMO

Chemical communication relating to predation risk is a trait common among fish species. Prey fish under threat of predation can signal risk to conspecific fish, which then exhibit defensive responses. Fish also assess predation risk by visual cues and change their behavior accordingly. Here, we explored whether these behavioral changes act as visual alarm signals to conspecific fish that are not initially under risk. We show that shoals of zebrafish (Danio rerio) visually exposed to a predator display antipredator behaviors. In addition, these defensive maneuvers trigger antipredator reactions in conspecifics and, concomitantly, stimulate the hypothalamus-pituitary-interrenal axis, leading to cortisol increase. Thus, we conclude that zebrafish defensive behaviors act as visual alarm cues that induce antipredator and stress response in conspecific fish.

2.
Gen Comp Endocrinol ; 252: 236-238, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28716505

RESUMO

In this article, we show that the tyrosine hydroxylase inhibitor α-Methyl-l-tyrosine (AMPT) decreased the responsiveness of the zebrafish stress axis to an acute stressful challenge. These effects were specific for responses to stimulation, since unstimulated (basal) cortisol levels were not altered by AMPT. Moreover, AMPT decreased the stress response 15min after stimulation, but not after that time period. To our knowledge, this is the first report about the effects of AMPT on the neuroendocrine axis of adult zebrafish in acute stress responses. Overall, these results suggest a mechanism of catecholamine-glucocorticoid interplay in neuroendocrine responses of fish, pointing an interesting avenue for physiological research, as well as an important endpoint that can be disrupted by environmental contamination. Further experiments will unravel the mechanisms by which AMPT blocked the cortisol response.


Assuntos
Inibidores Enzimáticos/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Tirosina 3-Mono-Oxigenase/antagonistas & inibidores , Peixe-Zebra/fisiologia , alfa-Metiltirosina/farmacologia , Animais , Feminino , Hidrocortisona/sangue , Masculino , Tirosina 3-Mono-Oxigenase/metabolismo , Peixe-Zebra/sangue
3.
Sci Rep ; 6: 37612, 2016 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-27874070

RESUMO

Here we provide, at least to our knowledge, the first evidence that aripiprazole (APPZ) in the water blunts the stress response of exposed fish in a concentration ten times lower than the concentration detected in the environment. Although the mechanism of APPZ in the neuroendocrine axis is not yet determined, our results highlight that the presence of APPZ residues in the environment may interfere with the stress responses in fish. Since an adequate stress response is crucial to restore fish homeostasis after stressors, fish with impaired stress response may have trouble to cope with natural and/or imposed stressors with consequences to their welfare and survival.


Assuntos
Aripiprazol/toxicidade , Estresse Fisiológico/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Feminino , Hidrocortisona/metabolismo , Masculino
4.
Arch Environ Contam Toxicol ; 71(3): 415-22, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27423874

RESUMO

In agriculture intensive areas, fishponds and natural water bodies located in close proximity to these fields receive water with variable amounts of agrichemicals. Consequently, toxic compounds reach nontarget organisms. For instance, aquatic organisms can be exposed to tebuconazole-based fungicides (TBF), glyphosate-based herbicides (GBH), and atrazine-based herbicides (ABH) that are potentially dangerous, which motivates the following question: Are these agrichemicals attractant or aversive to fish? To answer this question, adult zebrafish were tested in a chamber that allows fish to escape from or seek a lane of contaminated water. This attraction and aversion paradigm was evaluated with zebrafish in the presence of an acute contamination with these compounds. We showed that only GBH was aversive to fish, whereas ABH and TBF caused neither attraction nor aversion for zebrafish. Thus, these chemicals do not impose an extra toxic risk by being an attractant for fish, although TBF and ABH can be more deleterious, because they induce no aversive response. Because the uptake and bioaccumulation of chemicals in fish seems to be time- and dose-dependent, a fish that remains longer in the presence of these substances tends to absorb higher concentrations than one that escapes from contaminated sites.


Assuntos
Agroquímicos/toxicidade , Peixes/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Aprendizagem da Esquiva , Comportamento Animal , Testes de Toxicidade , Peixe-Zebra
5.
Pharmacol Biochem Behav ; 139 Pt B: 121-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26261019

RESUMO

Despite the recent advances in understanding the pathophysiology of anxiety disorders, the pharmacological treatments currently available are limited in efficacy and induce serious side effects. A possible strategy to achieve clinical benefits is drug repurposing, i.e., discovery of novel applications for old drugs, bringing new treatment options to the market and to the patients who need them. N-acetylcysteine (NAC), a commonly used mucolytic and paracetamol antidote, has emerged as a promising molecule for the treatment of several neuropsychiatric disorders. The mechanism of action of this drug is complex, and involves modulation of antioxidant, inflammatory, neurotrophic and glutamate pathways. Here we evaluated the effects of NAC on behavioral parameters relevant to anxiety in zebrafish. NAC did not alter behavioral parameters in the novel tank test, prevented the anxiety-like behaviors induced by an acute stressor (net chasing), and increased the time zebrafish spent in the lit side in the light/dark test. These data may indicate that NAC presents an anti-stress effect, with the potential to prevent stress-induced psychiatric disorders such as anxiety and depression. The considerable homology between mammalian and zebrafish genomes invests the current data with translational validity for the further clinical trials needed to substantiate the use of NAC in anxiety disorders.


Assuntos
Acetilcisteína/farmacologia , Ansiolíticos/farmacologia , Ansiedade/prevenção & controle , Peixe-Zebra/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Estresse Fisiológico , Pesquisa Médica Translacional
6.
Physiol Behav ; 139: 182-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25449397

RESUMO

Here, we show that individually housed zebrafish presented a reduced cortisol response to an acute stressor (persecution with a pen net for 120 s) compared to zebrafish housed in groups of 10. We hypothesized that the cortisol response to stress was reduced in individually housed zebrafish because they depend solely on their own perceptions of the stressor, whereas among grouped zebrafish, the stress response might be augmented by chemical and/or behavioral cues from the other members of the shoal. This hypothesis was based on previous described chemical communication of stress in fish as well on individual variation in stressor perception and potential individual differences in fish personality.


Assuntos
Hidrocortisona/metabolismo , Comportamento Social , Isolamento Social , Estresse Psicológico/fisiopatologia , Peixe-Zebra/fisiologia , Animais , Feminino , Abrigo para Animais , Masculino , Percepção , Isolamento Social/psicologia
7.
Chemosphere ; 112: 85-91, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25048892

RESUMO

We studied the stress response of Rhamdia quelen fingerlings at 45, 90, 135 and 180 d following acute exposure to agrichemicals. Herein, we report the novel observation that acute exposure of fingerling-aged fish to a methyl parathion-based insecticide (MPBI) and to a tebuconazole-based fungicide (TBF) induced chronic inhibition of the stress response. In contrast, fish exposed to an atrazine-simazine-based herbicide (ASBH) recovered the stress response on day 45, and fish exposed to a glyphosate-based herbicide (GBH) did not present stress response inhibition. Additionally, fish exposed to MPBI, GBH and ASBH showed lower survival rates and attained lower final weights. In the case of TBF, the presence of the stressful stimulus more strongly influenced the changes in the performance parameters than did the agrichemical exposure itself. An impairment of the cortisol response may seriously hamper the adaptive response and the ability to promote the necessary metabolic and ionic adjustments to respond to environmental stress.


Assuntos
Peixes-Gato/fisiologia , Hidrocortisona/antagonistas & inibidores , Praguicidas/toxicidade , Estresse Fisiológico/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Metil Paration/toxicidade , Taxa de Sobrevida , Fatores de Tempo
8.
PLoS One ; 8(10): e75780, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24116073

RESUMO

The effects of ethanol exposure on Danio rerio have been studied from the perspectives of developmental biology and behavior. However, little is known about the effects of ethanol on the prey-predator relationship and chemical communication of predation risk. Here, we showed that visual contact with a predator triggers stress axis activation in zebrafish. We also observed a typical stress response in zebrafish receiving water from these conspecifics, indicating that these fish chemically communicate predation risk. Our work is the first to demonstrate how alcohol effects this prey-predator interaction. We showed for the first time that alcohol exposure completely blocks stress axis activation in both fish seeing the predator and in fish that come in indirect contact with a predator by receiving water from these conspecifics. Together with other research results and with the translational relevance of this fish species, our data points to zebrafish as a promising animal model to study human alcoholism.


Assuntos
Comunicação Animal , Comportamento Animal/efeitos dos fármacos , Etanol/farmacologia , Comportamento Predatório/efeitos dos fármacos , Animais , Comportamento Animal/fisiologia , Hidrocortisona/metabolismo , Comportamento Predatório/fisiologia , Estresse Fisiológico/fisiologia , Peixe-Zebra/metabolismo
9.
PLoS One ; 8(10): e74499, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24098336

RESUMO

In southern South America and other parts of the world, aquaculture is an activity that complements agriculture. Small amounts of agrichemicals can reach aquaculture ponds, which results in numerous problems caused by oxidative stress in non-target organisms. Substances that can prevent or reverse agrichemical-induced oxidative damage may be used to combat these effects. This study includes four experiments. In each experiment, 96 mixed-sex, 6-month-old Rhamdia quelen (118±15 g) were distributed into eight experimental groups: a control group that was not exposed to contaminated water, three groups that were exposed to various concentrations of bee products, three groups that were exposed to various concentrations of bee products plus tebuconazole (TEB; Folicur 200 CE™) and a group that was exposed to 0.88 mg L(-1) of TEB alone (corresponding to 16.6% of the 96-h LC50). We show that waterborne bee products, including royal jelly (RJ), honey (H), bee pollen (BP) and propolis (P), reversed the oxidative damage caused by exposure to TEB. These effects were likely caused by the high polyphenol contents of these bee-derived compounds. The most likely mechanism of action for the protective effects of bee products against tissue oxidation and the resultant damage is that the enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) are increased.


Assuntos
Antioxidantes/farmacologia , Abelhas/metabolismo , Peixes-Gato/metabolismo , Fungicidas Industriais/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Triazóis/toxicidade , Animais , Mel/análise , Pólen/metabolismo
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