MDPV (3,4-methylenedioxypyrovalerone) administered to mice during development of the central nervous system produces persistent learning and memory impairments.

Background: Synthetic cathinones (SC) constitute the second most frequently abused class of new psychoactive substances. They serve as an alternative to classic psychostimulatory drugs of abuse, such as methamphetamine, cocaine, or 3,4-methylenedioxymethamphetamine (MDMA). Despite the worldwide prevalence of SC, little is known about their long-term impact on the central nervous system.

Astrocytes of the Anterior Commissure Regulate the Axon Guidance Pathways of Newly Generated Neocortical Neurons in the Opossum .

In marsupials, upper-layer cortical neurons derived from the progenitors of the subventricular zone of the lateral ventricle (SVZ) mature morphologically and send their axons to form interhemispheric connections through the anterior commissure. In contrast, eutherians have evolved a new extra callosal pathway, the corpus callosum, that interconnects both hemispheres. In this study, we aimed to examine neurogenesis during the formation of cortical upper layers, including their morphological maturation in a marsupial species, namely the opossum ().

Adult Neurogenesis in the Mammalian Hypothalamus: Impact of Newly Generated Neurons on Hypothalamic Function.

In mammals, adult neurogenesis was first demonstrated in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus of the hippocampal formation. Further research showed that adult neurogenesis persists in other brain structures, such as the cerebral cortex, piriform cortex, striatum, amygdala, and hypothalamus. However, the origin of newly generated cells in these structures is not clear.

Postnatal and Adult Neurogenesis in Mammals, Including Marsupials.

In mammals, neurogenesis occurs during both embryonic and postnatal development. In eutherians, most brain structures develop embryonically; conversely, in marsupials, a number of brain structures develop after birth. The exception is the generation of granule cells in the dentate gyrus, olfactory bulb, and cerebellum of eutherian species.

Effects of Brain Size on Adult Neurogenesis in Shrews.

Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size.

Impaired olfactory neurogenesis affects the performance of olfactory-guided behavior in aged female opossums.

Increasing evidence has indicated that adult neurogenesis contributes to brain plasticity, although function of new neurons is still under debate. In opossums, we performed an olfactory-guided behavior task and examined the association between olfactory discrimination-guided behavior and adult neurogenesis in the olfactory bulb (OB). We found that young and aged opossums of either sex learned to find food buried in litter using olfactory cues.

Corrigendum: Downregulation of TrkC Receptors Increases Dendritic Arborization of Purkinje Cells in the Developing Cerebellum of the Opossum, .

[This corrects the article DOI: 10.3389/fnana.2020.

Downregulation of TrkC Receptors Increases Dendritic Arborization of Purkinje Cells in the Developing Cerebellum of the Opossum, .

In therian mammals, the cerebellum is one of the late developing structures in the brain. Specifically, the proliferation of cerebellar granule cells occurs after birth, and even in humans, the generation of these cells continues during the first year of life. The main difference between marsupials and eutherians is that the majority of the brain structures in marsupials develop after birth.

Aged Opossums Show Alterations in Spatial Learning Behavior and Reduced Neurogenesis in the Dentate Gyrus.

In many mammalian species including opossums, adult neurogenesis, the function of which is not completely understood, declines with aging. Aging also causes impairment of cognition. To understand whether new neurons contribute to learning and memory, we performed experiments on young and aged laboratory opossums, , and examined the association between spatial memory using the Morris water maze test and the rate of adult neurogenesis in the dentate gyrus (DG).

Inhibition of TrkB- and TrkC-Signaling Pathways Affects Neurogenesis in the Opossum Developing Neocortex.

We have previously reported that the blockage of TrkB and TrkC signaling in primary culture of opossum neocortical cells affects neurogenesis that involves a range of processes including cell proliferation, differentiation, and survival. Here, we studied whether TrkB and TrkC activity specifically affects various types of progenitor cell populations during neocortex formation in the Monodelphis opossum in vivo. We found that the inhibition of TrkB and TrkC activities affects the same proliferative cellular phenotype, but TrkC causes more pronounced changes in the rate of cell divisions.

Roles of the exon junction complex components in the central nervous system: a mini review.

The exon junction complex (EJC) consists of four core proteins: Magoh, RNA-binding motif 8A (Rbm8a, also known as Y14), eukaryotic initiation factor 4A3 (eIF4A3, also known as DDX48), and metastatic lymph node 51 (MLN51, also known as Casc3 or Barentsz), which are involved in the regulation of many processes occurring between gene transcription and protein translation. Its main role is to assemble into spliceosomes at the exon-exon junction of mRNA during splicing. It is, therefore, a range of functions concerning post-splicing events such as mRNA translocation, translation, and nonsense-mediated mRNA decay (NMD).

CacyBP/SIP, a Hsp90 binding chaperone, in cellular stress response.

CacyBP/SIP interacts with Hsp90 and is able to protect proteins from denaturation and/or aggregation induced by elevated temperature. In this work we studied the influence of different stress factors on CacyBP/SIP level in HEp-2 cells. We have found that HO and radicicol treatment resulted in a significant increase (up to 40%) in the CacyBP/SIP level.

Stress-Dependent Changes in the CacyBP/SIP Interacting Protein S100A6 in the Mouse Brain.

The CacyBP/SIP target S100A6 is widely present in the nervous system, and its up-regulation is associated with certain neurodegenerative diseases. Here, we examined the involvement of S100A6 protein in stress responses in mice. Using Western blotting, we observed a marked change in brainstem structures, whereby stressed mice showed approximately one-third the protein level produced in the control group.

The expression of interleukin-6 and its receptor in various brain regions and their roles in exploratory behavior and stress responses.

We examined the involvement of interleukin-6 (IL-6) and its receptor IL-6Rα on behavior and stress responses in mice. In the open field, both wild-type (WT) and IL-6 deficient mice displayed similar levels of locomotor activity; however, IL-6 deficient mice spent more time in the central part of the arena compared to control WT mice. After behavioral testing, mice were subjected to stress and then sacrificed.

Distribution and function of TrkB receptors in the developing brain of the opossum Monodelphis domestica.

The expression, development pattern, spatiotemporal distribution, and function of TrkB receptors were investigated during the postnatal brain development of the opossum. Full-length TrkB receptor expression was detectable in the newborn opossum, whereas three different short forms that are expressed in the adult brain were almost undetectable in the newborn opossum brain. The highest level of full-length TrkB receptor expression was observed at P35, which corresponds to the time of eye opening.

Expression of TrkC receptors in the developing brain of the Monodelphis opossum and its effect on the development of cortical cells.

In this study, we investigated the distribution, localization and several various functions of TrkC receptors during development of the Monodelphisopossum brain. Western blotting analysis showed that two different forms of the TrkC receptor, the full-length receptor and one of its truncated forms, are abundantly expressed in the opossum brain. The expression of TrkC receptors was barely detected in the brain of newborn opossums.

Lipopolysaccharide injected to pregnant mice affects behavior of their offspring in adulthood.

We studied consequences of maternal immune response on the course of pregnancy and the behavior of adult offspring. Mice in late gestation (day 16-17) were injected with lipopolysaccharide (LPS). Treatment of pregnant mice with high doses of LPS resulted in fetal resorption or stillbirths.

Neurotrophins and their receptors in early development of the mammalian nervous system.

Neurotrophins belonging to the class of growth factors and including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5) are widely recognized as essential factors in the developing central nervous system (CNS). Neurotrophins are synthesized as precursor forms (proneurotrophins). Mature forms of neurotrophins exert their effect by binding to specific tyrosine kinases receptors (TrkA, TrkB and TrkC) as well as via the p75 receptor, a member of the tumor necrosis factor receptor superfamily while proneurotrophins interact with the receptor p75 or co-receptor complex of p75 and sortilin, that is a Vps10p domain-containing transmembrane protein.

Adult neurogenesis in the hedgehog (Erinaceus concolor) and mole (Talpa europaea).

We investigated adult neurogenesis in two species of mammals belonging to the superorder Laurasiatheria, the southern white-breasted hedgehog (order Erinaceomorpha, species Erinaceus concolor) from Armenia and the European mole (order Soricomorpha, species Talpa europaea) from Poland. Neurogenesis in the brain of these species was examined immunohistochemically, using the endogenous markers doublecortin (DCX) and Ki-67, which are highly conserved among species. We found that in both the hedgehog and mole, like in the majority of earlier investigated mammals, neurogenesis continues in the subventricular zone (SVZ) of the lateral ventricles and in the dentate gyrus (DG).

Thalamic nuclei in the opossum Monodelphis domestica.

We investigated nuclear divisions of the thalamus in the gray short-tailed opossum (Monodelphis domestica) to gain detailed information for further developmental and comparative studies. Nissl and myelin staining, histochemistry for acetylcholinesterase and immunohistochemistry for calretinin and parvalbumin were performed on parallel series of sections. Many features of the Monodelphis opossum thalamus resemble those in Didelphis and small eutherians showing no particular sensory specializations, particularly in small murid rodents.

Generation recruitment and death of brain cells throughout the life cycle of Sorex shrews (Lipotyphla).

Young shrews of the genus Sorex that are born in early summer reduce their body size before wintering, including a reduction of brain weight of 10-30%. In the spring they mature sexually, double their body weight and regain about half of the loss in brain weight. To investigate the mechanisms of brain weight oscillations we studied the rate of cell death and generation in the brain during the whole life cycle of the common shrew (Sorex araneus) and pygmy shrew (S.

Trk signaling regulates neural precursor cell proliferation and differentiation during cortical development.

Increasing evidence indicates that development of embryonic central nervous system precursors is tightly regulated by extrinsic cues located in the local environment. Here, we asked whether neurotrophin-mediated signaling through Trk tyrosine kinase receptors is important for embryonic cortical precursor cell development. These studies demonstrate that inhibition of TrkB (Ntrk2) and/or TrkC (Ntrk3) signaling using dominant-negative Trk receptors, or genetic knockdown of TrkB using shRNA, caused a decrease in embryonic precursor cell proliferation both in culture and in vivo.

Development and plasticity of the retina in the opossum Monodelphis domestica.

We investigated the rate of cell proliferation and death in the retina of the Monodelphis opossum during its postnatal development and the influence of early monocular enucleation on these processes. Our results show that in the opossum, as in other marsupials, the peak of the retinal cells divisions occurs postnatally and that generation of retinal cells continues till the time of eye opening (P34), except of the marginal rim, where it continued till P60. Ganglion and amacrine cells are generated between postnatal days (P) P4 and P9, while bipolar cells and photoreceptors are generated simultaneously between P14 and P25.

Apparent scarcity of glial fibrillary acidic protein expression in the brain of the pygmy shrew Sorex minutus as revealed by immunocytochemistry.

We examined astroglial cells in the brain of the pygmy shrew Sorex minutus (Insectivora). For that purpose we labeled glial fibrillary acidic protein (GFAP) immunohistochemically in brain sections with a polyclonal antibody. Antigen retrieval experiments were performed to counteract formaldehyde fixation masking of GFAP epitopes.