System Of Vertebrates Research Articles

A screen of pharmacologically active compounds to identify modulators of the Adgrg6/Gpr126 signalling pathway in zebrafish embryos.

Adhesion G protein-coupled receptors (GPCRs) are an underrepresented class of GPCRs in drug discovery. We previously developed an in vivo drug screening pipeline to identify compounds with agonist activity for Adgrg6 (Gpr126), an adhesion GPCR required for myelination of the peripheral nervous system in vertebrates. The screening assay tests for rescue of an ear defect found in adgrg6tb233c-/- hypomorphic homozygous mutant zebrafish, using the expression of versican b (vcanb) mRNA as an easily identifiable phenotype. In the current study, we used the same assay to screen a commercially available library of 1280 diverse bioactive compounds (Sigma LOPAC). Comparison with published hits from two partially overlapping compound collections (Spectrum, Tocris) confirms that the screening assay is robust and reproducible. Using a modified counter screen for myelin basic protein (mbp) gene expression, we have identified 17 LOPAC compounds that can rescue both inner ear and myelination defects in adgrg6tb233c-/- hypomorphic mutants, three of which (ebastine, S-methylisothiourea hemisulfate, and thapsigargin) are new hits. A further 25 LOPAC hit compounds were effective at rescuing the otic vcanb expression but not mbp. Together, these and previously identified hits provide a wealth of starting material for the development of novel and specific pharmacological modulators of Adgrg6 receptor activity.

Role of the mechanisms for antibody repertoire diversification in monoclonal light chain deposition disorders: when a friend becomes foe.

The adaptive immune system of jawed vertebrates generates a highly diverse repertoire of antibodies to meet the antigenic challenges of a constantly evolving biological ecosystem. Most of the diversity is generated by two mechanisms: V(D)J gene recombination and somatic hypermutation (SHM). SHM introduces changes in the variable domain of antibodies, mostly in the regions that form the paratope, yielding antibodies with higher antigen binding affinity. However, antigen recognition is only possible if the antibody folds into a stable functional conformation. Therefore, a key force determining the survival of B cell clones undergoing somatic hypermutation is the ability of the mutated heavy and light chains to efficiently fold and assemble into a functional antibody. The antibody is the structural context where the selection of the somatic mutations occurs, and where both the heavy and light chains benefit from protective mechanisms that counteract the potentially deleterious impact of the changes. However, in patients with monoclonal gammopathies, the proliferating plasma cell clone may overproduce the light chain, which is then secreted into the bloodstream. This places the light chain out of the protective context provided by the quaternary structure of the antibody, increasing the risk of misfolding and aggregation due to destabilizing somatic mutations. Light chain-derived (AL) amyloidosis, light chain deposition disease (LCDD), Fanconi syndrome, and myeloma (cast) nephropathy are a diverse group of diseases derived from the pathologic aggregation of light chains, in which somatic mutations are recognized to play a role. In this review, we address the mechanisms by which somatic mutations promote the misfolding and pathological aggregation of the light chains, with an emphasis on AL amyloidosis. We also analyze the contribution of the variable domain (VL) gene segments and somatic mutations on light chain cytotoxicity, organ tropism, and structure of the AL fibrils. Finally, we analyze the most recent advances in the development of computational algorithms to predict the role of somatic mutations in the cardiotoxicity of amyloidogenic light chains and discuss the challenges and perspectives that this approach faces.

Structural and expression analysis of the dopamine receptors reveals their crucial roles in regulating the insulin signaling pathway in oysters

Dopamine performs its critical role upon binding to receptors. Since dopamine receptors are numerous and versatile, understanding their protein structures and evolution status, and identifying the key receptors involved in the modulation of insulin signaling will provide essential clues to investigate the molecular mechanism of neuroendocrine regulating the growth in invertebrates. In this study, seven dopamine receptors were identified in the Pacific oysters (Crassostrea gigas) and were classified into four subtypes according to their protein secondary and tertiary structures, and ligand-binding activities. Of which, DR2 (dopamine receptor 2) and D(2)RA-like (D(2) dopamine receptor A-like) were considered the invertebrate-specific type 1 and type 2 dopamine receptors, respectively. Expression analysis indicated that the DR2 and D(2)RA-like were highly expressed in the fast-growing oyster “Haida No.1”. After in vitro incubation of ganglia and adductor muscle with exogenous dopamine and dopamine receptor antagonists, the expression of these two dopamine receptors and ILPs (insulin-like peptides) was also significantly affected. Dual-fluorescence in situ hybridization results showed that D(2)RA-like and DR2 were co-localized with MIRP3 (molluscan insulin-related peptide 3) and MIRP3-like (molluscan insulin-related peptide 3-like) in the visceral ganglia, and were co-localized with ILP (insulin-like peptide) in the adductor muscle. Furthermore, the downstream components of dopamine signaling, including PKA, ERK, CREB, CaMKK1, AKT, and GSK3β were also significantly affected by the exogenous dopamine and dopamine receptor antagonists. These findings confirmed that dopamine might affect the secretion of ILPs through the invertebrate-specific dopamine receptors D(2)RA-like and DR2, and thus played crucial roles in the growth regulation of the Pacific oysters. Our study establishes the potential regulatory relationship between the dopaminergic system and insulin-like signaling pathway in marine invertebrates.

Ecology of fear: predator avoidance reduces seed dispersal in an ant.

The ecology of fear refers to the non-fatal cost that predators and parasites impose on prey populations. These non-consumptive effects (NCEs) can influence animal-plant interactions, but evidence thereof comes mainly from vertebrate systems with less focus on invertebrates. Here, I investigated whether the foraging behaviour of the ant Ectatomma ruidum was influenced by its primary predator, the forest toad Rhinella alata. In field tests, the probability of seed removal by the ants was 25% for seeds placed with the forest toad compared to 32% for control seeds, suggesting that toads reduce ant foraging rates. A further experiment revealed that ants which had previously encountered the predator and its faeces were more likely (59%) than inexperienced ants (50%) to avoid the exit with the predator faeces. This outcome suggests that ants are capable of learning cues associated with predation risk, possibly leading to NCEs. This indicates that predators can exert NCEs on invertebrate prey with potential cascading effects on seed dispersal, extending results previously seen only in vertebrate seed dispersal systems.

Docking Analysis of Deltamethrin Pesticide with MHC I and MHC II Molecules to Establish Immunomodulation Effects

Background: Deltamethrin is a class II synthetic pyrethroid pesticide extensively used to control pests and vectors in the agriculture sector and health management programme. Due to excessive applications of this pesticide in the environment, it is harming many organisms other than the target organisms. Higher organisms like human beings are also affected by this pesticide because it instigates the impairment of the central nervous system and also distresses the immune system of vertebrates. Methods: In the current research study, MHC I and MHC II molecules of human origin have been targeted to evaluate the interaction with deltamethrin molecules by the AutoDock tool to establish the immunomodulatory effect. MHC I receptor molecule is presented on every nucleated cell, and MHC II receptors are located specifically on cell surfaces of antigen-presenting cells. These receptors play a role in cell-mediated and humoral immune responses. The binding affinity of deltamethrin with MHC receptors can affect the immune response, specifically the acquired immunity of an individual. Results: Findings of the current research study support that deltamethrin causes the suppression of the immune system by interaction with MHC I and MHC II molecules and may cause the organisms to be more prone towards antigen and disease development. Conclusion: The autoDock tool can be utilized to analyse other pesticides’ effects on the immune system and in the drug development process to minimize the toxic effects due to several types of pesticides.

Characterization of Glutamate-Gated Chloride Channel in Tribolium castaneum.

The glutamate-gated chloride channels (GluCls) play essential roles in signal transduction by regulating fast inhibitory synaptic transmission in the nervous system of invertebrates. While there is only one GluCl subunit in the insect, the diversity of insect GluCls is broadened by alternative splicing. In the present study, three TcGluCl variant genes were cloned from the red flour beetle Tribolium castaneum. Analysis of the characteristics of TcGluCls including sequence features, genomic structures, and alternative splicing revealed that TcGluCls had the typical structural features of GluCls and showed high homologies with the GluCls from other insect orders. The TcGluCl-encoding gene consists of nine exons and three variants (TcGluCl-3a, TcGluCl-3b, and TcGluCl-3c) were generated by the alternative splicing of exon 3, which was a highly conserved alternative splicing site in insect GluCls. Homology modeling of TcGluCl-3a showed that the exon 3 coding protein located at the N-terminal extracellular domain, and there were no steric clashes encountered between the exon 3 coding region and ivermectin/glutamate binding pocket, which indicated that the alternative splicing of exon 3 might have no impact on the binding of GluCls to glutamate and insecticide. In addition to the head tissue, TcGluCl-3a and TcGluCl-3c also had high expressions in the ovary and testis of T. castaneum, whereas TcGluCl-3b showed high expression in the midgut, suggesting the diverse physiological functions of TcGluCl variants in T. castaneum. The total TcGluCl and three variants showed the highest expression levels in the early stage larvae. The expressions of TcGluCl, TcGluCl-3b, and TcGluCl-3c were significantly increased from the late-stage larvae to the early stage pupae and indicated that the TcGluCl might be involved in the growth and development of T. castaneum. These results are helpful to further understand the molecular characteristics of insect GluCls and provide foundations for studying the specific function of the GluCl variant.

Major histocompatibility complex: history of discovery, evolution, structure, significance in transplantation of allogeneic hematopoietic stem cells

Aim. To reveal the significance of the major histocompatibility complex and the human leukocyte antigen evolutionary divergence in transplantation of allogeneic hematopoietic stem cells. The article traces the evolution of the major histocompatibility complex and discusses the reasons for its formation on the example of the recognition system of invertebrates, plants, jawed vertebrates and humans. The concepts of immunopeptidome and human leukocyte antigen evolutionary divergence have been defined; and the data on their impact on the therapy outcomes in patients with hemoblastosis have been presented. The impact of the major histocompatibility complex incompatibility on transplantation outcomes has been disclosed.

Red blood cells of Labeo rohita express Toll-like receptors, NOD- like receptors, interleukins, and interferon-I in response to Gram-negative bacterial infections and lipopolysaccharide stimulations.

Red blood cells (RBCs) are the most abundant cell types in the circulatory system of vertebrates. In fish, RBCs retain their nuclei throughout their lifetime and remain transcriptionally and translationally active. While their primary function is typically associated with gas exchange, recent reports indicate that nucleated red blood cells can play a significant role in regulating the body's innate immune response. The current article describes the innate immune role of red blood cells in rohu (Labeo rohita), a freshwater fish species that holds significant commercial importance in India and South-East Asian nations. From the whole blood and mucosal surface RBCs have been isolated through density gradient centrifugation with HiSep™LSM 1077 (density 1.007 ± 0.0010) and their purity has been confirmed by the Giemsa staining followed by microscopical observations. Toll-like receptors (TLR2, 3, 4, 5) and nucleotide oligomerization domain (NOD)-like receptors (NOD1 and NOD2) in RBCs of rohu fingerlings were observed to be significantly activated (P < 0.05) on infection with Aeromonas hydrophila and Edwardsiella tarda. This activation resulted in increased expression of interleukins (IL-8, IL-1β) and interferon (IFN)-I genes. The activation of TLR4, NOD1 and NOD2, as well as the expression of interleukins and IFN-I genes have been observed in both in vivo and in vitro stimulation of rohu RBCs with lipopolysaccharides. These findings highlight the importance of fish RBCs in enhancing innate immunity against various pathogenic invasions in rohu.

Neural innervation in adipose tissue, gut, pancreas, and liver

Abstract Efficient communication between the brain and peripheral organs is indispensable for regulating physiological function and maintaining energy homeostasis. The peripheral nervous system (PNS) in vertebrates, consisting of the autonomic and somatic nervous systems, bridges the peripheral organs and the central nervous system (CNS). Metabolic signals are processed by both vagal sensory nerves and somatosensory nerves. The CNS receives sensory inputs via ascending nerves, serves as the coordination and integration center, and subsequently controls internal organs and glands via descending nerves. The autonomic nervous system consists of sympathetic and parasympathetic branches that project peripheral nerves into various anatomical locations to regulate the energy balance. Sympathetic and parasympathetic nerves typically control the reflexive and involuntary functions in organs. In this review article, we outline the innervation of adipose tissue, gut, pancreas, and liver, to illustrate the neurobiological basis of central–peripheral interactions. We emphasize the importance of understanding the functional atlas of neural control of energy metabolism, and more importantly, provide potential avenues for further research in this area.

Characteristics and expression profiles of MHC class Ⅰ molecules in Carassius auratus.

Major histocompatibility complex class Ⅰ (MHC Ⅰ) molecules play a vital role in adaptive immune systems in vertebrates by presenting antigens to effector T cells. Understanding the expression profiling of MHC Ⅰ molecules in fish is essential for improving our knowledge of the relationship between microbial infection and adaptive immunity. In this study, we conducted a comprehensive analysis of MHC Ⅰ gene characteristics in Carassius auratus, an important freshwater aquaculture fish in China that is susceptible to Cyprinid herpesvirus 2 (CyHV-2) infection. We identified approximately 20 MHC Ⅰ genes discussed, including U, Z, and L lineage genes. However, only U and Z lineage proteins were identified in the kidney of Carassius auratus using high pH reversed-phase chromatography and mass spectrometry. The L lineage proteins were either not expressed or present at an extremely low level in the kidneys of Carassius auratus. We also used targeted proteomics to analyze changes in protein MHC Ⅰ molecules abundance in healthy and CyHV-2-infected Carassius auratus. We observed that five MHC Ⅰ molecules were upregulated, and Caau-UFA was downregulated in the diseased group. This study is the first to reveal the expression of MHC Ⅰ molecules at a large scale in Cyprinids, which enhances our understanding of fish adaptive immune systems.

Rapid and precise genome engineering in a naturally short-lived vertebrate.

The African turquoise killifish is a powerful vertebrate system to study complex phenotypes at scale, including aging and age-related disease. Here, we develop a rapid and precise CRISPR/Cas9-mediated knock-in approach in the killifish. We show its efficient application to precisely insert fluorescent reporters of different sizes at various genomic loci in order to drive cell-type- and tissue-specific expression. This knock-in method should allow the establishment of humanized disease models and the development of cell-type-specific molecular probes for studying complex vertebrate biology.

The African killifish: A short-lived vertebrate model to study the biology of sarcopenia and longevity.

Sarcopenia, the age-related decline in muscle function, places a considerable burden on health-care systems. While the stereotypic hallmarks of sarcopenia are well characterized, their contribution to muscle wasting remains elusive, which is partly due to the limited availability of animal models. Here, we have performed cellular and molecular characterization of skeletal muscle from the African killifish-an extremely short-lived vertebrate-revealing that while many characteristics deteriorate with increasing age, supporting the use of killifish as a model for sarcopenia research, some features surprisingly reverse to an "early-life" state in the extremely old stages. This suggests that in extremely old animals, there may be mechanisms that prevent further deterioration of skeletal muscle, contributing to an extension of life span. In line with this, we report a reduction in mortality rates in extremely old killifish. To identify mechanisms for this phenomenon, we used a systems metabolomics approach, which revealed that during aging there is a striking depletion of triglycerides, mimicking a state of calorie restriction. This results in the activation of mitohormesis, increasing Sirt1 levels, which improves lipid metabolism and maintains nutrient homeostasis in extremely old animals. Pharmacological induction of Sirt1 in aged animals was sufficient to induce a late life-like metabolic profile, supporting its role in life span extension in vertebrate populations that are naturally long-lived. Collectively, our results demonstrate that killifish are not only a novel model to study the biological processes that govern sarcopenia, but they also provide a unique vertebrate system to dissect the regulation of longevity.

Trained immunity from the perspective of Plasmodium infection.

The immune system of vertebrates includes innate immunity and adaptive immunity, and the network between them enables the host to fight against invasions of various pathogens. Recently, studies discovered that immune memory is one of the features of innate immunity, breaking the previous opinion that immune memory exists only in adaptive immunity. Immune memory supports innate immune cells to respond efficiently upon reinfection or restimulation. During the Plasmodium infection, the innate immune system is the first to be triggered, and innate immune cells are activated by components from Plasmodium or Plasmodium-infected red blood cells. Innate immune cells could be induced to develop memory after the activation and may play an important role in the subsequent infection of Plasmodium or other pathogens and stimulation. This review will discuss the recent findings relevant to trained immunity and Plasmodium infection, facilitating the understanding of the role of trained immunity in malaria and other diseases and the development of therapeutic strategies based on trained immunity.

Investigating the functional roles of TNFSF13 family members in Cartilaginous Fishes

Abstract The TNFSF13 cytokines BAFF and APRIL along with their cognate receptors BAFFR, TACI, and BCMA play critical parts in the development, function, and maintenance of B cells in mammals. Despite the well-studied roles that BAFF and APRIL play in the immune systems of higher vertebrates, their evolutionary history and functions in non-mammalian organisms are not well understood. Recently, our lab has demonstrated that collectively the TNFSF is evolutionarily ancient, with most of its members having evolved over 450 million years ago in the jawed vertebrate ancestor. Interestingly, we found that despite the evolutionary ancient position of cartilaginous fishes, their repertoire of TNFSF is just as complex as higher vertebrates with evidence of lineage specific TNFSF members that are absent in more evolutionary recent taxa. Specifically, cartilaginous fishes possess two additional TNFSF13 family members, namely BALM (TNFSF13C) and a retrotransposed duplicate of BAFF (iBAFF). Thus, cartilaginous fishes possess four TNFSF13 members whose functional roles remain unexplored. Here we demonstrate the tissue specific expression of BAFF, iBAFF, BALM, and APRIL, as well as their anticipated receptors BAFFR, TACI, and BCMA in the nurse shark. Additionally, we explore receptor-ligand interactions using a yeast surface display assay aiming to understand the role(s) each plays in the development and maintenance of shark B cells. Such information is key to understanding the evolutionary history of this key cytokine family.

The thymus and T-cell ontogeny in ballan wrasse (Labrus bergylta) is nutritionally modelled.

Marine fish larvae often experience high mortality unrelated to predation during early life stages, and farmed ballan wrasse (Labrus bergylta) is no exception. Knowing when the adaptive immune system is developed and fully functional, and how nutrition may modulate these processes is therefore of importance to establish effective prophylactic measures and will also extend the relatively limited knowledge on the immune system in lower vertebrates. The thymus anlage of ballan wrasse was found to be histologically visible for the first time at larval stage 3 (20-30 days post hatch, dph) and becomes lymphoid at stage 5 (50-60 dph) correlating with an increase of T-cell marker transcripts. At this stage, a clear zonation into a RAG1+ cortex and a RAG1- CD3ϵ+ medulla was distinguished, indicating that T-cell maturation processes in ballan wrasse are similar to other teleosts. The higher abundance of CD4-1+ compared to CD8β+ cells in the thymus together with the apparent lack of CD8β+ cells in gill, gut, and pharynx, where CD4-1+ cells were identified, indicates that helper T-cells have a more prominent role during larval development compared to cytotoxic T-cells. As ballan wrasse lacks a stomach but has an exceptionally high IgM expression in the hindgut, we hypothesize that helper T-cells are crucial for activation and recruitment of IgM+ B-cells and possibly other leukocytes to the gut during early development. Nutritional factors such as DHA/EPA, Zn and Se may lead to an earlier expression of certain T-cell markers as well as a larger size of the thymus, indicating an earlier onset of adaptive immunity. Including live feeds that supplies the larva with higher amounts of these nutrients can therefore be beneficial for ballan wrasse farming.

Dendrite regeneration mediates functional recovery after complete dendrite removal.

Unlike many cell types, neurons are not typically replaced if damaged. Therefore, regeneration of damaged cellular domains is critical for maintenance of neuronal function. While axon regeneration has been documented for several hundred years, it has only recently become possible to determine whether neurons respond to dendrite removal with regeneration. Regrowth of dendrite arbors has been documented in invertebrate and vertebrate model systems, but whether it leads to functional restoration of a circuit remains unknown. To test whether dendrite regeneration restores function, we used larval Drosophila nociceptive neurons. Their dendrites detect noxious stimuli to initiate escape behavior. Previous studies of Drosophila sensory neurons have shown that dendrites of single neurons regrow after laser severing. We removed dendrites from 16 neurons per animal to clear most of the dorsal surface of nociceptive innervation. As expected, this reduced aversive responses to noxious touch. Surprisingly, behavior was completely restored 24​h after injury, at the stage when dendrite regeneration has begun, but the new arbor has only covered a small portion of its former territory. This behavioral recovery required regenerative outgrowth as it was eliminated in a genetic background in which new growth is blocked. We conclude that dendrite regeneration can restore behavior.

Polycomb-like Proteins in Gene Regulation and Cancer.

Polycomb-like proteins (PCLs) are a crucial group of proteins associated with the Polycomb repressive complex 2 (PRC2) and are responsible for setting up the PRC2.1 subcomplex. In the vertebrate system, three homologous PCLs exist: PHF1 (PCL1), MTF2 (PCL2), and PHF19 (PCL3). Although the PCLs share a similar domain composition, they differ significantly in their primary sequence. PCLs play a critical role in targeting PRC2.1 to its genomic targets and regulating the functionality of PRC2. However, they also have PRC2-independent functions. In addition to their physiological roles, their dysregulation has been associated with various human cancers. In this review, we summarize the current understanding of the molecular mechanisms of the PCLs and how alterations in their functionality contribute to cancer development. We particularly highlight the nonoverlapping and partially opposing roles of the three PCLs in human cancer. Our review provides important insights into the biological significance of the PCLs and their potential as therapeutic targets for cancer treatment.

Reversible Photoreaction of a Retinal Photoisomerase, Retinal G-Protein-Coupled Receptor RGR.

Retinal G-protein-coupled receptor (RGR) plays a crucial role in the visual system of vertebrates as a retinal photoisomerase, which isomerizes all-trans-retinal to 11-cis-retinal to maintain the photosensitivity of visual rhodopsins. Despite the previous characterization of bovine RGR, little is known about the spectral properties of RGR from other species. In addition, photoreactivity of the 11-cis-retinal-binding form remains unclear. In this study, we revealed that human and chicken RGRs form blue-absorbing pigments similar to bovine RGR. Furthermore, the spectroscopic and biochemical analyses revealed that bovine and chicken RGRs are bistable rhodopsins displaying a reversible photoreaction. These findings provide insight into the behavior of RGR as a retinal photoisomerase and aid in understanding its role in the visual system.

Endocrine Disorders Associated with Medicinal Products: Approaches to Preclinical Safety Assessment

The endocrine system coordinates almost all organs and other systems in vertebrates. In particular, it regulates such important biological functions as metabolism, development, reproduction, and behaviour. To date, a significant amount of information has accumulated on endocrine disorders associated with chemical compounds (endocrine disruptors) used in various fields of human activity. The aim of this study was to evaluate the possibility of preclinical risk assessment for the endocrine function disorders attributable to new medicinal products. Endocrine disruptors are associated with a wide range of adverse events, including developmental problems arising from functional abnormalities of the endocrine system. Endocrine disorders caused by endocrine-disrupting chemicals are characterised by a long latency period between exposure and manifestation of a dysfunction; a nonlinear dose–response relationship; and a linear correlation of damage severity to exposure timing and duration. The chemicals influence the endocrine system through multiple mechanisms, the main of which being the interaction with cellular receptors sensitive to certain hormones and the influence on gene expression, intracellular signalling, and hormone transport, etc. This paper discusses the possibility of using hormone levels as indicators of endocrine disruption and presents the literature and authors’ own data on normal levels of relevant hormones in the blood of animals. An analysis of animal blood hormone levels in preclinical programmes will provide an opportunity to evaluate potential iatrogenic risks.

Evolutionary morphology of spinal nodes of poikilotherm vertebrate animals

An important issue of modern neuromorphology of animals is the study of spinal cord nodes, which play an important role as primary centers on the way to transmit sensory information from receptors to the central nervous system, providing appropriate reactions to the action of certain factors. The scientific article uses material that is a fragment of the research work of the department of normal and pathological morphology, hygiene and expertise “Development, morphology and histochemistry of animal organs in normal and pathological conditions”, state registration number – 0120U100796. Using anatomical, morphological, neurohistological and statistical methods of research, the histomorphology of spinal cord nodes in a comparative anatomical series of vertebrates: bony fish, amphibians, reptiles, which differ in motor activity and their place of existence in a certain environment, was clarified in the work. It has been established that in the process of phylogenesis, a certain structural and morphofunctional reorganization of the spinal nodes occurs. They differ in shape and size. Adaptation to various living conditions of animals was formed on the basis of changes in the density and size of neurons, their morphological structures, an increase in the total number of gliocytes and glial cells, and polymorphism in the degree of chromatophilia. Thus, according to neurohistological studies, it has been noted that the neurons of the spinal cord nodes of cold-blooded animals (pond frog, pond lizard) are characterized by a functional degree of relative polymorphism – chromatophilia. With the total impregnation of the spinal cord nodes with silver nitrate according to the Bolshovsky-Gross method, different intensity of staining of nerve cells is found in all the studied animals: light, light-dark and dark. It was found that the neurocytes of all groups of vertebrates differ in the volume of the perikaryon, the nucleus and the nuclear-cytoplasmic ratio, which is related to the peculiarities of species and age-related neuromorphology, the morpho-functional state of the nervous system and the type of higher nervous activity. Nissl staining of histopreparations of spinal nodes of poikilothermic animals showed that the neuroplasm of nerve cells of spinal nodes contains deep basophilic substances in the form of small grains of varying density. In carp neurons, the basophilic substance is concentrated on the periphery of the dust-like neuroplasm. Nuclear chromatin is more pronounced in the pond frog than in the carp, the depths of which are much larger. It should be noted that the highest degree of development of the protein-synthesizing apparatus is characteristic of the neurocytes of the spinal nodes of the swift lizard, compared to the previously studied vertebrates. The obtained research results have not only important general biological significance, which complements and expands modern scientific ideas about certain regularities of morpho-functional rearrangements of spinal cord nodes in a comparative anatomical series, but also serve to develop new material and substantiate the morpho-functional assessment of species morphological differences of the nervous system of poikilothermic vertebrates, adapted to different conditions of existence in the environment.