Cross-species analyses of intra-species behavioral differences in mammals and fish

Multiple species display robust behavioral variance among individuals due to different genetic, genomic, epigenetic, neuroplasticity and environmental factors. Behavioral individuality has been extensively studied in various animal models, including rodents and other mammals. Fish, such as zebrafish (Danio rerio), have recently emerged as powerful aquatic model organisms with overt individual differences in behavioral, nociceptive and other CNS traits. Here, we evaluate individual behavioral differences in mammals and fish, emphasizing the importance of cross-species analyses of intraspecies variance in experimental models of normal and pathological CNS function

Evaluation of thermal conductivity of organic phase-change materials from equilibrium and non-equilibrium computer simulations: Paraffin as a test case

An accurate in silico evaluation of the thermal conductivity is critical for improving the thermal properties of organic phase-change materials on a rational basis. To explore the impact of a theoretical model on the computed thermal conductivity, here we employed the equilibrium and the non-equilibrium molecular dynamics (MD) simulations to study paraffin (n-eicosane) bulk samples, in both crystalline and liquid states, with the use of 10 atomistic force fields, both all-atom and united-atom ones. Overall, we found that the equilibrium MD method is preferable for computing the thermal conductivity of n-eicosane samples (at least for a 10-nm-size simulation box). For the n-eicosane crystals, the all-atom models provide larger thermal conductivity coefficients than their united-atom counterparts and, correspondingly, a better match with the experimental data. This is most likely because the crystalline lattice of the models with explicit hydrogen atoms is additionally stabilized by the electrostatic interactions. In contrast, in the liquid state, most all-atom models overestimate the experimental data for n-eicosane, providing thereby worse performance as compared to the united-atom force fields. However, when it comes to the experimentally observed increase in the thermal conductivity of n-eicosane samples upon crystallization, only all-atom models are able to reproduce quantitatively the experimental data. Each force field of n-eicosane was also characterized by an overall score which accumulated the deviations of the computed thermal conductivity coefficients from the experimental values, for both crystalline and liquid samples. It turns out that the best performance among 10 atomistic models of n-eicosane is observed for the all-atom GAFF force field. All in all, our study clearly demonstrates that a proper choice of the model for computing the thermal conductivity is a non-trivial task: even for such relatively simple compounds as paraffins (n-alkanes), different models perform quite differently, in equilibrium and in non-equilibrium MD simulations, as well as in crystalline and liquid phases

Opioid Neurobiology, Neurogenetics and Neuropharmacology in Zebrafish

Despite the high prevalence of medicinal use and abuse of opioids, their neurobiology and mechanisms of action are not fully understood. Experimental (animal) models are critical for improving our understanding of opioid effects in vivo. As zebrafish (Danio rerio) are increasingly utilized as a powerful model organism in neuroscience research, mounting evidence suggests these fish as a useful tool to study opioid neurobiology. Here, we discuss the zebrafish opioid system with specific focus on opioid gene expression, existing genetic models, as well as its pharmacological and developmental regulation. As many human brain diseases involve pain and aberrant reward, we also summarize zebrafish models relevant to opioid regulation of pain and addiction, including evidence of functional interplay between the opioid system and central dopaminergic and other neurotransmitter mechanisms. Additionally, we critically evaluate the limitations of zebrafish models for translational opioid research and emphasize their developing utility for improving our understanding of evolutionarily conserved mechanisms of pain-related, addictive, affective and other behaviors, as well as for fostering opioid-related drug discovery. (C) 2019 IBRO. Published by Elsevier Ltd. All rights reserved

Developing zebrafish experimental animal models relevant to schizophrenia

Schizophrenia is a severely debilitating, lifelong psychiatric disorder affecting approximately 1% of global population. The pathobiology of schizophrenia remains poorly understood, necessitating further translational research in this field. Experimental (animal) models are becoming indispensable for studying schizophrenia-related phenotypes and pro/antipsychotic drugs. Mounting evidence suggests the zebrafish (Danio rerio) as a useful tool to model various phenotypes relevant to schizophrenia. In addition to their complex robust behaviors, zebrafish possess high genetic and physiological homology to humans, and are also sensitive to drugs known to reduce or promote schizophrenia clinically. Here, we summarize findings on zebrafish application to modeling schizophrenia, as well as discuss recent progress and remaining challenges in this field. We also emphasize the need in further development and wider use of zebrafish models for schizophrenia to better understand its pathogenesis and enhance the search for new effective antipsychotics