Inter-Strain Differences in the Lumbar Spinal Cord Anatomy and Neuromorphology: Wistar Versus Dark Agouti Rats.

Rat strains differ in physiology, behavior, and recovery after central nervous system injury. To assess these differences, we compared the gross and local anatomy and neuromorphology of the lumbar spinal cord of the Wistar and Dark Agouti (DA) strains. The key findings include (i) distinct spatial relationships between vertebrae and spinal segments in the two strains; (ii) Wistar rats have larger volumes of spinal cord gray and white matter; (iii) DA rats have smaller total neuronal populations, thus indicating an expectation of smaller local neuronal populations; (iv) this expectation was confirmed for interneurons expressing calbindin 28 kDa. But contrary to expectations, (v) DA rats had more numerous populations of the interneurons expressing parvalbumin and a population of α-motoneurons. Consequently, these strains displayed divergent ratios in specific spinal neuronal populations. Researchers should consider these inter-strain differences when comparing data across different strains.

Beyond Barrels: Diverse Thalamocortical Projection Motifs in the Mouse Ventral Posterior Complex.

Thalamocortical pathways from the rodent ventral posterior (VP) thalamic complex to the somatosensory cerebral cortex areas are a key model in modern neuroscience. However, beyond the intensively studied projection from medial VP (VPM) to the primary somatosensory area (S1), the wiring of these pathways remains poorly characterized. We combined micropopulation tract-tracing and single-cell transfection experiments to map the pathways arising from different portions of the VP complex in male mice. We found that pathways originating from different VP regions show differences in area/lamina arborization pattern and axonal varicosity size. Neurons from the rostral VPM subnucleus innervate trigeminal S1 in point-to-point fashion. In contrast, a caudal VPM subnucleus innervates heavily and topographically second somatosensory area (S2), but not S1. Neurons in a third, intermediate VPM subnucleus innervate through branched axons both S1 and S2, with markedly different laminar patterns in each area. A small anterodorsal subnucleus selectively innervates dysgranular S1. The parvicellular VPM subnucleus selectively targets the insular cortex and adjacent portions of S1 and S2. Neurons in the rostral part of the lateral VP nucleus (VPL) innervate spinal S1, while caudal VPL neurons simultaneously target S1 and S2. Rostral and caudal VP nuclei show complementary patterns of calcium-binding protein expression. In addition to the cortex, neurons in caudal VP subnuclei target the sensorimotor striatum. Our finding of a massive projection from VP to S2 separate from the VP projections to S1 adds critical anatomical evidence to the notion that different somatosensory submodalities are processed in parallel in S1 and S2.

Reduction in neurons immunoreactive for calcium-binding proteins in the anteroventral thalamic nuclei of individuals with Down syndrome.

The anterior thalamic nuclei are important for cognition, and memory in particular. However, little is known about how the anterior thalamic nuclei are affected in many neurological disorders partly due to difficulties in selective segmentation in in vivo scans, due to their size and location. Post-mortem studies, therefore, remain a valuable source of information about the status of the anterior thalamic nuclei. We used post-mortem tissue to assess the status of the anteroventral thalamic nucleus in Down syndrome using samples from males and females ranging from 22-65 years in age and comparing to tissue from age matched controls. As expected, there was increased beta-amyloid plaque expression in the Down syndrome group. While there was a significant increase in neuronal density in the Down syndrome group, the values showed more variation consistent with a heterogeneous population. The surface area of the anteroventral thalamic nucleus was smaller in the Down syndrome group suggesting the increased neuronal density was due to greater neuronal packing but likely fewer overall neurons. There was a marked reduction in the proportion of neurons immunoreactive for the calcium-binding proteins calbindin, calretinin, and parvalbumin in individuals with Down syndrome. These findings highlight the vulnerability of calcium-binding proteins in the anteroventral nucleus in Down syndrome, which could both be driven by, and exacerbate, Alzheimer-related pathology in this region.

The impact of the mesoprefrontal dopaminergic system on the maturation of interneurons in the murine prefrontal cortex.

The prefrontal cortex (PFC) undergoes a protracted maturation process. This is true both for local interneurons and for innervation from midbrain dopaminergic (mDA) neurons. In the striatum, dopaminergic (DA) neurotransmission is required for the maturation of medium spiny neurons during a critical developmental period. To investigate whether DA innervation influences the maturation of interneurons in the PFC, we used a conditional knockout (cKO) mouse model in which innervation from mDA neurons to the mPFC (mesoprefrontal innnervation) is not established during development. In this mouse model, the maturation of parvalbumin (PV) and calbindin (CB) interneuron populations in the PFC is dysregulated during a critical period in adolescence with changes persisting into adulthood. PV interneurons are particularly vulnerable to lack of mesoprefrontal input, showing an inability to maintain adequate PV expression with a concomitant decrease in Gad1 expression levels. Interestingly, lack of mesoprefrontal innervation does not appear to induce compensatory changes such as upregulation of DA receptor expression in PFC neurons or increased innervation density of other neuromodulatory (serotonergic and noradrenergic) innervation. In conclusion, our study shows that adolescence is a sensitive period during which mesoprefrontal input plays a critical role in promoting the maturation of specific interneuron subgroups. The results of this study will help to understand how a dysregulated mesoprefrontal DA system contributes to the pathophysiology of neurodevelopmental disorders.

Inner Structure of the Lateral Geniculate Complex of Adult and Newborn Acomys cahirinus.

Acomys cahirinus is a unique Rodentia species with several distinctive physiological traits, such as precocial development and remarkable regenerative abilities. These characteristics render A. cahirinus increasingly valuable for regenerative and developmental physiology studies. Despite this, the structure and postnatal development of the central nervous system in A. cahirinus have been inadequately explored, with only sporadic data available. This study is the first in a series of papers addressing these gaps. Our first objective was to characterize the structure of the main visual thalamic region, the lateral geniculate complex, using several neuronal markers (including Ca2+-binding proteins, glutamic acid decarboxylase enzyme, and non-phosphorylated domains of heavy-chain neurofilaments) to label populations of principal neurons and interneurons in adult and newborn A. cahirinus. As typically found in other rodents, we identified three subdivisions in the geniculate complex: the dorsal and ventral lateral geniculate nuclei (LGNd and LGNv) and the intergeniculate leaflet (IGL). Additionally, we characterized internal diversity in the LGN nuclei. The "shell" and "core" regions of the LGNd were identified using calretinin in adults and newborns. In adults, the inner and outer parts of the LGNv were identified using calbindin, calretinin, parvalbumin, GAD67, and SMI-32, whereas in newborns, calretinin and SMI-32 were employed for this purpose. Our findings revealed more pronounced developmental changes in LGNd compared to LGNv and IGL, suggesting that LGNd is less mature at birth and more influenced by visual experience.

The amygdaloid body of the family Delphinidae: a morphological study of its central nucleus through calbindin-D28k.

Introduction: The amygdala is a noticeable bilateral structure in the medial temporal lobe and it is composed of at least 13 different nuclei and cortical areas, subdivided into the deep nuclei, the superficial nuclei, and the remaining nuclei which contain the central nucleus (CeA). CeA mediates the behavioral and physiological responses associated with fear and anxiety through pituitary-adrenal responses by modulating the liberation of the hypothalamic Corticotropin Releasing Factor/Hormone. Methods: Five dolphins of three different species, belonging to the family Delphinidae (three striped dolphins, one common dolphin, and one Atlantic spotted dolphin), were used for this study. For a precise overview of the CeA's structure, thionine staining and the immunoperoxidase method using calbindin D-28k were employed. Results: CeA extended mainly dorsal to the lateral nucleus and ventral to the striatum. It was medial to the internal capsule and lateral to the optic tract and the medial nucleus of the amygdala. Discussion: The dolphin amygdaloid complex resembles that of primates, including the subdivision, volume, and location of the CeA.

Cortical dysmorphology and reduced cortico-collicular projections in an animal model of autism spectrum disorder.

Autism spectrum disorder is a neurodevelopmental disability that includes sensory disturbances. Hearing is frequently affected and ranges from deafness to hypersensitivity. In utero exposure to the antiepileptic valproic acid is associated with increased risk of autism spectrum disorder in humans and timed valproic acid exposure is a biologically relevant and validated animal model of autism spectrum disorder. Valproic acid-exposed rats have fewer neurons in their auditory brainstem and thalamus, fewer calbindin-positive neurons, reduced ascending projections to the midbrain and thalamus, elevated thresholds, and delayed auditory brainstem responses. Additionally, in the auditory cortex, valproic acid exposure results in abnormal responses, decreased phase-locking, elevated thresholds, and abnormal tonotopic maps. We therefore hypothesized that in utero, valproic acid exposure would result in fewer neurons in auditory cortex, neuronal dysmorphology, fewer calbindin-positive neurons, and reduced connectivity. We approached this hypothesis using morphometric analyses, immunohistochemistry, and retrograde tract tracing. We found thinner cortical layers but no changes in the density of neurons, smaller pyramidal and non-pyramidal neurons in several regions, fewer neurons immunoreactive for calbindin-positive, and fewer cortical neurons projecting to the inferior colliculus. These results support the widespread impact of the auditory system in autism spectrum disorder and valproic acid-exposed animals and emphasize the utility of simple, noninvasive auditory screening for autism spectrum disorder.

Cerebellum Purkinje cell vulnerability in aged rats with memory impairment.

The cerebellum is involved in higher order cognitive function and is susceptible to age-related atrophy. However, limited evidence has directly examined the cerebellum's role in cognitive aging. To interrogate potential substrates of the relationship between cerebellar structure and memory in aging, here we target the Purkinje cells (PCs). The sole output neurons of the cerebellum, PC loss and/or degeneration underlie a variety of behavioral abnormalities. Using a rat model of normal cognitive aging, we immunostained sections through the cerebellum for the PC-specific protein, calbindin-D28k. Although morphometric quantification revealed no significant difference in total PC number as a function of age or cognitive status, regional cell number was a more robust correlate of memory performance in the young cerebellum than in aged animals. Parallel biochemical analysis of PC-specific protein levels in whole cerebellum additionally revealed that calbindin-D28k and Purkinje cell protein-2 (pcp-2) levels were lower selectively in aged rats with spatial memory impairment compared to both young animals and aged rats with intact memory. These results suggest that cognitive aging is associated with cerebellum vulnerability, potentially reflecting disruption of the cerebellum-medial temporal lobe network.

Distribution of calcium-binding proteins immunoreactivity in the bottlenose dolphin entorhinal cortex.

Introduction: The entorhinal cortex has been shown to be involved in high-level cognitive functions in terrestrial mammals. It can be divided into two main areas: the lateral entorhinal area (LEA) and the medial entorhinal area (MEA). Understanding of its structural organization in cetaceans is particularly important given the extensive evidence for their cognitive abilities. The present study describes the cytoarchitectural and immunohistochemical properties of the entorhinal cortex of the bottlenose dolphin (Tursiops truncatus, Montagu, 1821), perhaps the most studied cetacean species and a paradigm for dolphins and other small cetaceans. Methods: Four bottlenose dolphins' entorhinal cortices were processed. To obtain a precise overview of the organization of the entorhinal cortex we used thionin staining to study its laminar and regional organization, and immunoperoxidase technique to investigate the immunohistochemical distribution of three most commonly used calcium-binding proteins (CBPs), calbindin D-28k (CB), calretinin (CR) and parvalbumin (PV). Entorhinal cortex layers thickness were measured, morphological and morphometric analysis for each layer were conducted and statistically compared. Results: Six layers in both the LEA and MEA were identified. The main difference between the LEA and the MEA is observed in layers II and III: the neurons in layer II of the LEA were denser and larger than the neurons in layer II of MEA. In addition, a relatively cell-free zone between layers II and III in LEA, but not in MEA, was observed. The immunohistochemical distribution of the three CBPs, CB, CR and PV were distinct in each layer. The immunostaining pattern of CR, on one side, and CB/PV, on the other side, appeared to be distributed in a complementary manner. PV and CB immunostaining was particularly evident in layers II and III, whereas CR immunoreactive neurons were distributed throughout all layers, especially in layers V and VI. Immunoreactivity was expressed by neurons belonging to different morphological classes: All CBPs were expressed in non-pyramidal neurons, but CB and CR were also found in pyramidal neurons. Discussion: The morphological characteristics of pyramidal and non-pyramidal neurons in the dolphin entorhinal cortex are similar to those described in the entorhinal cortex of other species, including primates and rodents. Interestingly, in primates, rodents, and dolphins, most of the CBP-containing neurons are found in the superficial layers, but the large CR-ir neurons are also abundant in the deep layers. Layers II and III of the entorhinal cortex contain neurons that give rise to the perforant pathway, which conveys most of the cortical information to the hippocampal formation. From the hippocampal formation, reciprocal projections are directed back to the deep layer of the entorhinal cortex, which distributes the information to the neocortex and subcortical area. Our data reveal that in the dolphin entorhinal cortex, the three major CBPs label morphologically heterogeneous groups of neurons that may be involved in the information flow between entorhinal input and output pathways.

Vitamin D, Calbindin, and calcium signaling: Unraveling the Alzheimer's connection.

Calcium is a ubiquitous second messenger that is indispensable in regulating neurotransmission and memory formation. A precise intracellular calcium level is achieved through the concerted action of calcium channels, and calcium exerts its effect by binding to an array of calcium-binding proteins, including calmodulin (CAM), calcium-calmodulin complex-dependent protein kinase-II (CAMK-II), calbindin (CAL), and calcineurin (CAN). Calbindin orchestrates a plethora of signaling events that regulate synaptic transmission and depolarizing signals. Vitamin D, an endogenous fat-soluble metabolite, is synthesized in the skin upon exposure to ultraviolet B radiation. It modulates calcium signaling by increasing the expression of the calcium-sensing receptor (CaSR), stimulating phospholipase C activity, and regulating the expression of calcium channels such as TRPV6. Vitamin D also modulates the activity of calcium-binding proteins, including CAM and calbindin, and increases their expression. Calbindin, a high-affinity calcium-binding protein, is involved in calcium buffering and transport in neurons. It has been shown to inhibit apoptosis and caspase-3 activity stimulated by presenilin 1 and 2 in AD. Whereas CAM, another calcium-binding protein, is implicated in regulating neurotransmitter release and memory formation by phosphorylating CAN, CAMK-II, and other calcium-regulated proteins. CAMK-II and CAN regulate actin-induced spine shape changes, which are further modulated by CAM. Low levels of both calbindin and vitamin D are attributed to the pathology of Alzheimer's disease. Further research on vitamin D via calbindin-CAMK-II signaling may provide newer insights, revealing novel therapeutic targets and strategies for treatment.

Brain circuits for retching-like behavior.

Nausea and vomiting are important defensive responses to cope with pathogens and toxins that invade the body. The nucleus of the solitary tract (NTS) is important for initiating these responses. However, the molecular heterogeneities and cellular diversities of the NTS occlude a better understanding of these defensive responses. Here, we constructed the single-nucleus transcriptomic atlas of NTS cells and found multiple populations of NTS neurons that may be involved in these defensive responses. Among these, we identified Calbindin1-positive (Calb1+) NTS neurons that are molecularly distinct from Tac1+ neurons. These Calb1+ neurons are critical for nausea and retching induced by cereulide; an emetic toxin secreted by Bacillus Cereus. Strikingly, we found that cereulide can directly modulate vagal sensory neurons that innervate Calb1+ NTS neurons, a novel mechanism distinct from that for nausea and retching induced by Staphylococcal enterotoxin A. Together, our transcriptomic atlas of NTS neurons and the functional analyses revealed the neural mechanism for cereulide-induced retching-like behavior. These results demonstrate the molecular and cellular complexities in the brain that underlie defensive responses to the diversities of pathogens and toxins.

Luteolin amends neural neurotransmitters, antioxidants, and inflammatory markers in the cerebral cortex of Adderall exposed rats.

BACKGROUND: Adderall is a central nervous system stimulant while luteolin has neuroprotective activity. This study aimed to determine whether luteolin can amend neural neurotransmitters, antioxidants, and inflammatory markers in the cerebral cortex of Adderall exposed rats. METHODS: Thirty-six male albino rats were divided into 6 equal groups, Control, Luteolin (1 g/kg)-treated, and Luteolin (2 g/kg)-treated groups: normal rats were orally administrated once a day with 2 ml distilled water, luteolin (1 g/kg), and luteolin (2 g/kg), respectively for 4 weeks. Adderall rats, Adderall rats + luteolin (1 g/kg)-treated, and Adderall rats + luteolin (2 g/kg)-treated groups: normal rats were orally administrated once a day with 10 mg/kg of Adderall, 3 days/week for 4 weeks, then these rats orally administrated daily once a day with 2 ml of distilled water, luteolin (1 g/kg), and luteolin (2 g/kg), respectively for another 4 weeks. RESULTS AND CONCLUSION: Adderall decreased superoxide dismutase, glutathione peroxidase, catalase, NADPH oxidase, interleukin-10, serotonin, dopamine, norepinephrine, γ-aminobutyric acid, and acetylcoline estrase but increased malondialdehyde, conjugated dienes, oxidative index, tumour necrosis factor-α, interleukin-1ß, and interleukin-6 levels in the cerebral cortex. Adderall increased the expression of glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, and anti-calbindin in the cerebral cortex of Adderall-treated rats. In Adderall-treated rats, daily oral administration of luteolin for 4 weeks brought all these parameters back to values that were close to control where higher dose was more effective than lower dose. The importance of this research is to provide natural compound that amends Adderall-related neural disturbances and this natural compound is cheap, avaliable without any side effect and it does not interfer with Adderall efficiency.

Beneficial Effect of Erythropoietin on Ameliorating Propionic Acid-Induced Autistic-Like Features in Young Rats.

Autism is a neurodevelopmental disorder that impairs communication and social interaction. This study investigated the possible beneficial effects of erythropoietin (EPO) on experimental autistic-like behaviors induced by propionic acid (PPA). Twenty-four rats were distributed into three groups: (i) control; (ii) PPA_Gp: daily injected subcutaneously with PPA for five consecutive days; PPA+EPO-Gp: injected with PPA, then received intraperitoneal injection of EPO once daily for two weeks. Behavioral changes in the rats were assessed. Specimens from the cerebellar hemispheres were subjected to histological and ultrastructure examination, immunohistochemistry for glial fibrillary acidic protein (GFAP) and calbindin-D28K, and biochemical analysis for glutathione peroxidase (GSH-Px), malondialdehyde (MDA), gamma amino-butyric acid (GABA), and serotonin. PPA-Gp showed significant behavioral impairment, with a significant depletion in GSH-px, GABA, and serotonin and a significant increase in MDA. Histological examination revealed reduced Purkinje cell count with ultrastructural degeneration, irregularly arranged nerve fibers in the molecular layer, astrogliosis, and significantly decreased calbindin-immunostaining compared to the control. EPO protected cerebellar structure, increased Purkinje cell count, improved neuronal morphology, reduced PPA-induced autistic-like features, alleviated neuronal oxidative stress, increased intercellular antioxidant levels, and suppressed inflammation. EPO provided significant protection against PPA-induced autistic features in rats, with structural preservation of Purkinje cells.

Localization of PDE4D, HCN1 channels, and mGluR3 in rhesus macaque entorhinal cortex may confer vulnerability in Alzheimer's disease.

Alzheimer's disease cortical tau pathology initiates in the layer II cell clusters of entorhinal cortex, but it is not known why these specific neurons are so vulnerable. Aging macaques exhibit the same qualitative pattern of tau pathology as humans, including initial pathology in layer II entorhinal cortex clusters, and thus can inform etiological factors driving selective vulnerability. Macaque data have already shown that susceptible neurons in dorsolateral prefrontal cortex express a "signature of flexibility" near glutamate synapses on spines, where cAMP-PKA magnification of calcium signaling opens nearby potassium and hyperpolarization-activated cyclic nucleotide-gated channels to dynamically alter synapse strength. This process is regulated by PDE4A/D, mGluR3, and calbindin, to prevent toxic calcium actions; regulatory actions that are lost with age/inflammation, leading to tau phosphorylation. The current study examined whether a similar "signature of flexibility" expresses in layer II entorhinal cortex, investigating the localization of PDE4D, mGluR3, and HCN1 channels. Results showed a similar pattern to dorsolateral prefrontal cortex, with PDE4D and mGluR3 positioned to regulate internal calcium release near glutamate synapses, and HCN1 channels concentrated on spines. As layer II entorhinal cortex stellate cells do not express calbindin, even when young, they may be particularly vulnerable to magnified calcium actions and ensuing tau pathology.

Hexa-Histidine, a Peptide with Versatile Applications in the Study of Amyloid-ß(1-42) Molecular Mechanisms of Action.

Amyloid ß (Aß) oligomers are the most neurotoxic forms of Aß, and Aß(1-42) is the prevalent Aß peptide found in the amyloid plaques of Alzheimer's disease patients. Aß(25-35) is the shortest peptide that retains the toxicity of Aß(1-42). Aß oligomers bind to calmodulin (CaM) and calbindin-D28k with dissociation constants in the nanomolar Aß(1-42) concentration range. Aß and histidine-rich proteins have a high affinity for transition metal ions Cu2+, Fe3+ and Zn2+. In this work, we show that the fluorescence of Aß(1-42) HiLyteTM-Fluor555 can be used to monitor hexa-histidine peptide (His6) interaction with Aß(1-42). The formation of His6/Aß(1-42) complexes is also supported by docking results yielded by the MDockPeP Server. Also, we found that micromolar concentrations of His6 block the increase in the fluorescence of Aß(1-42) HiLyteTM-Fluor555 produced by its interaction with the proteins CaM and calbindin-D28k. In addition, we found that the His6-tag provides a high-affinity site for the binding of Aß(1-42) and Aß(25-35) peptides to the human recombinant cytochrome b5 reductase, and sensitizes this enzyme to inhibition by these peptides. In conclusion, our results suggest that a His6-tag could provide a valuable new tool to experimentally direct the action of neurotoxic Aß peptides toward selected cellular targets.

Calbindin Has a Potential Spatiotemporal Correlation with Proliferation and Apoptosis in the Postnatal Rat Kidney.

The protein calbindin-D28k modulates calcium reabsorption in the kidney. Here, we aimed to study the influence of proliferation and apoptosis in different compartments of the kidney on the developmental function of calbindin. Using immunohistochemistry, we investigated the postnatal development of rats' kidneys by using calbindin, proliferative cell nuclear antigen (PCNA), and apoptotic single-stranded DNA (ssDNA). In the neonatal stage (1-day and 1-week-old rats), calbindin showed a positive reaction in the distal convoluted tubule (DCT), a short nephron segment between the macula densa, collecting ducts, and tubules. Moreover, the localization of calbindin was restricted to immature nephrons and mesenchymal tissues. Furthermore, PCNA immunoreactivity was moderate in early-developed podocytes with no reactivity in other renal tubules. The ssDNA immunoreactivity was moderate in the undifferentiated nephron. Then, in the mature stage (3 and 6 weeks old), there was an intense calbindin reaction in DCT but a moderate reaction to PCNA and ssDNA in podocytes. A more intense calbindin reactivity was found in the adult stage (2- and 3-month-old rats) in DCT and collecting tubules. Therefore, in this study, calbindin localization showed an inverse relationship with PCNA and ssDNA of the nephron compartments, which might reflect the efficiency of bone-building and muscle contraction during animal development.

S1P Lyase Deficiency in the Brain Promotes Astrogliosis and NLRP3 Inflammasome Activation via Purinergic Signaling.

Astrocytes are critical players in brain health and disease. Brain pathologies and lesions are usually accompanied by astroglial alterations known as reactive astrogliosis. Sphingosine 1-phosphate lyase (SGPL1) catalysis, the final step in sphingolipid catabolism, irreversibly cleaves its substrate sphingosine 1-phosphate (S1P). We have shown that neural ablation of SGPL1 causes accumulation of S1P and hence neuronal damage, cognitive deficits, as well as microglial activation. Moreover, the S1P/S1P-receptor signaling axis enhances ATP production in SGPL1-deficient astrocytes. Using immunohistochemical methods as well as RNA Seq and CUT&Tag we show how S1P signaling causes activation of the astrocytic purinoreceptor P2Y1 (P2Y1R). With specific pharmacological agonists and antagonists, we uncover the P2Y1R as the key player in S1P-induced astrogliosis, and DDX3X mediated the activation of the NLRP3 inflammasome, including caspase-1 and henceforward generation of interleukin-1ß (IL-1ß) and of other proinflammatory cytokines. Our results provide a novel route connecting S1P metabolism and signaling with astrogliosis and the activation of the NLRP3 inflammasome, a central player in neuroinflammation, known to be crucial for the pathogenesis of numerous brain illnesses. Thus, our study opens the door for new therapeutic strategies surrounding S1P metabolism and signaling in the brain.

Defining hippocampal area CA2 in the fox (Vulpes vulpes) brain.

Since 1959, the Russian Farm-Fox study has bred foxes to be either tame or, more recently, aggressive, and scientists have used them to gain insight into the brain structures associated with these behavioral features. In mice, hippocampal area CA2 has emerged as one of the essential regulators of social aggression, and so to eventually determine whether we could identify differences in CA2 between tame and aggressive foxes, we first sought to identify CA2 in foxes (Vulpes vulpes). As no clearly defined area of CA2 has been described in species such as cats, dogs, or pigs, it was not at all clear whether CA2 could be identified in foxes. In this study, we cut sections of temporal lobes from male and female red foxes, perpendicular to the long axis of the hippocampus, and stained them with markers of CA2 pyramidal cells commonly used in tissue from rats and mice. We observed that antibodies against Purkinje cell protein 4 best stained the pyramidal cells in the area spanning the end of the mossy fibers and the beginning of the pyramidal cells lacking mossy fibers, resembling the pattern seen in rats and mice. Our findings indicate that foxes do have a "molecularly defined" CA2, and further, they suggest that other carnivores like dogs and cats might as well. With this being the case, these foxes could be useful in future studies looking at CA2 as it relates to aggression.

Aging-associated increased nitric oxide production is a potential cause of inferior eggshell quality produced by aged laying hens.

It is important to prolong the productive life of laying hens without compromising their welfare. Therefore, in this study, we aimed to identify the cause for inferior quality egg production of aged hens by investigating the aging-associated molecular changes related to eggshell formation in the isthmic and uterine mucosae and determining whether nitric oxide plays a role in decreasing the quality of eggs produced by aged hens. Young (35 weeks old) and aged (130 weeks old) White Leghorn laying hens were used in this study to determine the effects of age on the expression of proteins related to eggshell membranes formation in the isthmus and eggshell biomineralization and nitric oxide production in the uterus. Nitric oxide synthesis during the ovulatory cycle was examined in twenty-five laying hens (46-52 weeks old) euthanized at 0, 4, 7, 16, and 24 h after oviposition. S-Nitroso-N-acetylpenicillamine (a nitric oxide donor) was added to the cultured isthmic and uterine mucosal cells to examine the effects of nitric oxide on the expression of genes related to eggshell membranes formation and eggshell biomineralization, respectively. The results showed that the protein abundance of collagen I and V in the isthmic mucosa and collagen V in the eggshell membranes were lower in aged hens than in young hens. The mRNA expression levels of calbindin, osteopontin, and ovocalyxin-36 and the protein abundance of calbindin and carbonic anhydrase-2 were lower in the uterine mucosa of aged hens than in that of young hens. Nitric oxide synthesis was higher in the uterine mucosa of aged hens than in that of young hens. Nitric oxide downregulated the mRNA expression levels of osteopontin and ovocalyxin-36 in cultured uterine mucosal cells. Our results indicated that the eggshell quality decreases with aging due to molecular changes in the uterine mucosa affecting the eggshell membrane formation and eggshell biomineralization. Moreover, nitric oxide overproduction may play a role in this dysfunction.

Seminal Calbindin 2 in Infertile Men With Varicocele: A Prospective Comparative Study.

The present study compared seminal calbindin 2 (CALB 2) levels and semen parameters in men with and without varicocele. CALB 2 is also known as calretinin and 29 kDa calbindin. The study was a case-control study conducted from April (2021) to March (2022) in the andrology department at Beni-Suef University hospital. The study included four matched groups: group (I) were controls (fertile normozoospermic men without varicocele) (n=24). Group (II) were fertile normozoospermic men with varicocele (n=24). Group (III) were infertile oligoasthenoteratozoospermia (OAT) men without varicocele (n=24). Group (IV) were infertile OAT men with varicocele (n=24). The lowest levels of seminal CALB 2 were found in patients with severe oligozoospermia which showed a statistically significant difference when compared to seminal CALB 2 in patients with normal, mildly low, or moderately low sperm counts. There were significant negative correlations between sperm concentration, sperm motility and percentage of normal sperm forms and seminal CALB 2. Seminal plasma CALB 2 may play a role in the negative impact of varicocele on the semen parameters especially sperm concentration, sperm motility and percentage of sperm normal forms. Future studies are needed to verify these findings.