Aggression in rainbow trout is inhibited by both MR and GR antagonists

Schjolden, Joachim; Basic, Dean; Winberg, Svante

doi:10.1016/j.physbeh.2009.09.018

Cited by 40 publications

(30 citation statements)

References 66 publications

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“…The mineralocorticoid system in fish may have biological actions in the brain and in behavior rather than in osmoregulation8121314, particularly in visuomotor performance, based on MR localization found in medaka ( Oryzias latipes ) in the present study. This fish is a useful model organism for studying these functions due to its tolerance to a wide range of salinities and several quantifiable behaviors.…”

supporting

confidence: 52%

Principal function of mineralocorticoid signaling suggested by constitutive knockout of the mineralocorticoid receptor in medaka fish

Sakamoto

Yoshiki

Takahashi

et al. 2016

Sci Rep

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As in osmoregulation, mineralocorticoid signaling is implicated in the control of brain-behavior actions. Nevertheless, the understanding of this role is limited, partly due to the mortality of mineralocorticoid receptor (MR)-knockout (KO) mice due to impaired Na+ reabsorption. In teleost fish, a distinct mineralocorticoid system has only been identified recently. Here, we generated a constitutive MR-KO medaka as the first adult-viable MR-KO animal, since MR expression is modest in osmoregulatory organs but high in the brain of adult medaka as for most teleosts. Hyper- and hypo-osmoregulation were normal in MR-KO medaka. When we studied the behavioral phenotypes based on the central MR localization, however, MR-KO medaka failed to track moving dots despite having an increase in acceleration of swimming. These findings reinforce previous results showing a minor role for mineralocorticoid signaling in fish osmoregulation, and provide the first convincing evidence that MR is required for normal locomotor activity in response to visual motion stimuli, but not for the recognition of these stimuli per se. We suggest that MR potentially integrates brain-behavioral and visual responses, which might be a conserved function of mineralocorticoid signaling through vertebrates. Importantly, this fish model allows for the possible identification of novel aspects of mineralocorticoid signaling.

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supporting

confidence: 52%

Principal function of mineralocorticoid signaling suggested by constitutive knockout of the mineralocorticoid receptor in medaka fish

Sakamoto

Yoshiki

Takahashi

et al. 2016

Sci Rep

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“…Fish have multiple GRs and a mineralocorticoid receptor (MR) to which cortisol can bind (Bury et al, 2003; Greenwood et al, 2003); RU486 selectively binds GRs (Remage-Healey and Bass, 2004; Schjolden et al, 2009; Wong and Herbert, 2005). In rodents, treatment with specific receptor agonists showed that, although GR activation alone has a significant effect on hippocampal cell proliferation, co-activation of GR and MR has a much larger effect (Wong and Herbert, 2005).…”

Section: Discussionmentioning

confidence: 99%

Glucocorticoid receptor blockade inhibits brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus

Dunlap¹,

Jashari²,

Pappas³

2011

Hormones and Behavior

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When animals are under stress, glucocorticoids commonly inhibit adult neurogenesis by acting through glucocorticoid receptors (GRs). However, in some cases, conditions that elevate glucocorticoids promote adult neurogenesis, and the role of glucocorticoid receptors in these circumstances is not well understood. We examined the involvement of GRs in social enhancement of brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus. In this species, long-term social interaction simultaneously elevates plasma cortisol, enhances brain cell addition and increases production of aggressive electrocommunication signals (“chirps”). We implanted isolated and paired fish with capsules containing nothing (controls) or the GR antagonist, RU486, recorded chirp production and locomotion for 7d, and measured the density of newborn cells in the periventricular zone. Compared to isolated controls, paired controls showed elevated chirping in two phases: much higher chirp rates in the first 5 h and moderately higher nocturnal rates thereafter. Treating paired fish with RU486 reduced chirp rates in both phases to those of isolated fish, demonstrating that GR activation is crucial for socially induced chirping. Neither RU486 nor social interaction affected locomotion. RU486 treatment to paired fish had a partial effect on cell addition: paired RU486 fish had less cell addition than paired control fish but more than isolated fish. This suggests that cortisol activation of GRs contributes to social enhancement of cell addition but works in parallel with another GR-independent mechanism. RU486 also reduced cell addition in isolated fish, indicating that GRs participate in the regulation of cell addition even when cortisol levels are low.

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“…Cortisol precipitates physiological and behavioural responses (1) extracellularly on the membrane of target cells and so mediate a rapid, direct action (non-genomic pathway) or (2) intracellularly so when the receptor-hormone complex diffuses into the nucleus in the target cell, it binds and acts as a transcription factor and either activates or represses one or several genes (a slower genomic pathway). The rapid effects of cortisol on behaviour are thought to occur through non-genomic pathways (Sandi 1996;Schjolden et al 2009;Mikics et al 2004). There are two types of receptors for cortisol: mineralocorticoid receptors (MR) and glucocorticoid receptors (GR).…”

Section: What Is Stress?mentioning

confidence: 99%

“…They also measured brain monoamines and suggested that the effects of cortisol on social status in fish may be mediated via the modulation of central signalling systems. Schjolden et al (2009) recently found that attack latency (but not the intensity of aggression) is affected by exogenous cortisol. In dyadic contests between individuals from rainbow trout strains with contrasting cortisol responsiveness, high cortisol responders lost more often than low cortisol responders reviewed in Øverli et al 2005).…”

Section: On Aggression and Social Hierarchy Position?mentioning

confidence: 99%

Cortisol and finfish welfare

Ellis

Yıldız

López‐Olmeda

et al. 2011

Fish Physiol Biochem

274

145

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Previous reviews of stress, and the stress hormone cortisol, in fish have focussed on physiology, due to interest in impacts on aquaculture production. Here, we discuss cortisol in relation to fish welfare. Cortisol is a readily measured component of the primary (neuroendocrine) stress response and is relevant to fish welfare as it affects physiological and brain functions and modifies behaviour. However, we argue that cortisol has little value if welfare is viewed purely from a functional (or behavioural) perspective-the cortisol response itself is a natural, adaptive response and is not predictive of coping as downstream impacts on function and behaviour are dose-, time- and context-dependent and not predictable. Nevertheless, we argue that welfare should be considered in terms of mental health and feelings, and that stress in relation to welfare should be viewed as psychological, rather than physiological. We contend that cortisol can be used (with caution) as a tractable indicator of how fish perceive (and feel about) their environment, psychological stress and feelings in fish. Cortisol responses are directly triggered by the brain and fish studies do indicate cortisol responses to psychological stressors, i.e., those with no direct physicochemical action. We discuss the practicalities of using cortisol to ask the fish themselves how they feel about husbandry practices and the culture environment. Single time point measurements of cortisol are of little value in assessing the stress level of fish as studies need to account for diurnal and seasonal variations, and environmental and genetic factors. Areas in need of greater clarity for the use of cortisol as an indicator of fish feelings are the separation of (physiological) stress from (psychological) distress, the separation of chronic stress from acclimation, and the interactions between feelings, cortisol, mood and behaviour.

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Aggression in rainbow trout is inhibited by both MR and GR antagonists

Cited by 40 publications

References 66 publications

Principal function of mineralocorticoid signaling suggested by constitutive knockout of the mineralocorticoid receptor in medaka fish

Principal function of mineralocorticoid signaling suggested by constitutive knockout of the mineralocorticoid receptor in medaka fish

Glucocorticoid receptor blockade inhibits brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus

Cortisol and finfish welfare

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