Biology subjects

Pejtsik, D.

Publications and source records attributed to Pejtsik, D..

4 recordsLinked to original sources

bioRxiv2024

Paradise fish (Macropodus opercularis) as novel translational model for emotional and cognitive function

Zebrafish have revolutionised physiological screening in vertebrates, but the interpretation of individual-based behavioural assays is burdened by the strong sociality of this species. We propose the use of a solitaire fish species, the paradise fish to keep the advantages and compensate for the limitations of the zebrafish model. We compared juvenile paradise fish and zebrafish in social and non-social exploratory tasks, anxiety tests and in a working memory assay to assess their performance in these individual-based models. We found that in contrast to zebrafish, paradise fish did not show social approach in the U-shape sociability test, their novelty exploration was not biased by the presence of a conspecific in the slalom test, and was not impaired by social isolation in the showjump or in the swimming plus-maze (SPM) anxiety tests. While social circumstances did not affect the anxiety of paradise fish, it was sensitive to the anxiolytic drug buspirone. Intra- and interest repeatability measures of the anxiety tests revealed that paradise fish express more consistent exploratory and defensive behaviours regarding time and context compared to zebrafish. Behavioural consistency in paradise fish was also supported by arm alternation as a predominant choice of exploration in the y-maze task. In summary, our results indicate that the behaviour of paradise fish is less biased by social cues and is more effective and repeatable in individual-based assays than zebrafish behaviour. We hypothesise that the two phenomena are connected and novelty exploration, anxiety and working memory can be more reliably measured and are translatable in a solitaire species.

animal behavior and cognition↗

bioRxiv2023

Improving anxiety research: novel approach to reveal trait anxiety through summary measures of multiple states

The reliability and validity of preclinical anxiety testing is essential for translating animal research into clinical use. However, the commonly used anxiety tests lack inter-test correlations and face challenges with repeatability. While translational animal research should be able to capture stable individual anxiety traits, the current approach employs a single type of test at a single time that only measures transient states of animals, heavily influenced by experimental conditions. Here, we propose a validated, optimized test battery capable of reliably capturing trait anxiety in rats and mice of both sexes. Instead of developing novel tests, we combined widely used tests (elevated plus-maze, open field and light-dark test) to provide instantly applicable adjustments for better predictive validity. We repeated these tests three times to capture behaviour across multiple challenges, which we combined to generate summary measures (SuMs). Our approach resolved between-test correlation issues and provided better predictions for subsequent outcomes under anxiogenic conditions or fear conditioning. SuMs were also able to reveal differences in anxiety in an etiological stress model. Finally, we tested our methods efficacy in discovering anxiety-related molecular pathways through RNA sequencing of the medial prefrontal cortex. Using SuMs, we identified four-times more molecular correlates of trait anxiety as compared to transient anxiety states, pointing out novel functional gene clusters. Furthermore, 16% of these molecular correlates of anxiety were replicated in amygdalar samples, as well. In summary, we provide a novel approach to capture trait anxiety in rodents, offering improved predictions for potential therapeutic targets for personalized medicine.

neuroscience↗

bioRxiv2019

Conserved serotonergic background of experience-dependent challenge-responding in zebrafish (Danio rerio)

Forming effective responses to threatening stimuli requires the adequate and coordinated emergence of stress-related internal states. Such ability depends on early-life experiences and, in connection, the adequate formation of neuromodulatory systems, particularly serotonergic signaling. Here, we assess the serotonergic background of experience-dependent behavioral responsiveness employing a zebrafish (Danio rerio) model. For the first time, we have characterized a period during the behavioral metamorphosis in which zebrafish are highly reactive to their environment. Absence of social stimuli during this phase established by isolated rearing fundamentally altered the behavioral phenotype of post-metamorphic zebrafish in a challenge-specific manner, partially due to a decline in responsiveness and an inability to develop stress-associated arousal state. In line with this, isolation differently affected whole-brain 5-HT signaling in resting and stress-induced conditions, an effect that was present at the level of the dorsal pallium and was negatively associated with responsiveness. Administration of the 5HT1AR partial agonist buspirone prevented the isolation-induced serotonin response to novelty in the forebrain and rescued stress-induced arousal along with challenge-induced behaviors, which altogether indicates a functional connection between these changes. In summary, there is a consistent negative association between behavioral responsiveness and serotonergic signaling in zebrafish, which is well recognizable through the modifying effects of developmental perturbation and pharmacological manipulations as well. Our results imply a conserved serotonergic mechanism that context-dependently modulates environmental reactivity and is highly sensitive to experiences acquired during a specific early-life time-window, a phenomenon that was previously only suggested in mammals.\n\nSignificance statementThe ability to respond to challenges is a fundamental factor in survival. We show that zebrafish that lack appropriate social stimuli in a sensitive developmental period show exacerbated alertness in non-stressful conditions while failing to react adequately to stressors. This shift is reflected inversely by central serotonergic signaling, a system that is implicated in numerous mental disorders in humans. Serotonergic changes in brain regions modulating responsivity and behavioral impairment were both prevented by the pharmacological blockade of serotonergic function. These results imply a serotonergic mechanism in zebrafish that transmits early-life experiences to the later phenotype by shaping stress-dependent behavioral reactivity, a phenomenon that was previously only suggested in mammals. Zebrafish provide new insights into early-life-dependent neuromodulation of behavioral stress-responses.

neuroscience↗

bioRxiv2018

The swimming plus-maze test: a novel high-throughput model for assessment of anxiety-related behaviour in larval zebrafish. (Danio rerio)

Larval zebrafish (Danio rerio) has the potential to supplement rodent models due to the availability of resource efficient methods implying high-throughput screening and high-resolution imaging techniques. Although behavioural models are available in larvae, only a few, insensitive approaches can be employed to assess anxiety. Here we present the swimming plus-maze (SPM) test paradigm to assess anxiety-related states in young zebrafish. The \"+\" shaped apparatus consists of arms of different depth representing differentially aversive context. The paradigm was validated i.) in larval and juvenile zebrafish, ii.) after administration of compounds affecting human anxiety and iii.) in differentially aversive experimental conditions. Furthermore, we compared the SPM with conventional \"anxiety tests\" of larvae such as the open tank and light/dark tank tests to identify their shared characteristics. We clarified that the preference towards deeper water is conserved trough the ontogenesis and can be abolished by anxiolytic or enhanced by anxiogenic agents, respectively. The behavioural read-out is insensitive to the aversiveness of the platform and unrelated to behaviours assessed by conventional tests utilizing larval fish. Taken together, we developed a sensitive high-throughput test measuring anxiety-related responses of larval zebrafish, which likely reflect bottom-dwelling behaviour of adults, potentially supporting larva-based integrative approaches.

animal behavior and cognition↗