Calbindin D28k Research Articles

Immunohistochemical Localization of Calbindin D28k, Parvalbumin, and Calretinin in the Superior Olivary Complex of Circling Mice

The circling mouse serves as a hearing loss model. It has spontaneous tmie gene mutations that cause hair cell and cochlear degeneration. However, little is known about the role of the tmie gene in superior olivary complex (SOC) regions, in which sound information from the two ears is integrated and primarily relayed to the nuclei of the lateral lemniscus and inferior colliculus. Several studies have reported that abnormal calcium (Ca²⁺) homeostasis is associated with the pathology of hearing loss. This study investigated the distribution of Ca²⁺-binding proteins (CaBPs), such as calbindin D28k, parvalbumin, and calretinin, in the SOC of the circling mouse on postnatal day 16. A comparison of wild-type (+/+), heterozygous (+/cir), and homozygous (cir/cir) mice showed that CaBP immunoreactivity was significantly decreased in the auditory nucleus of the SOC of homozygous (cir/cir) mice. A decline in the CaBPs level in the SOC may be the result of hearing loss through hair cell and cochlear degeneration following tmie gene mutation.

The Immunoreactivity of Calbindin on Cerebellum Cortex and Hippocampus of Mice Brain After One Week Exposure To Radiofrequency Radiation.

Background & Objectives:Radiofrequency radiation affects the calcium permeability and accordingly this induces pathophysiological changes in the brain and its subsequent output in the brain as tumor genesis, neural degeneration, and cognition or behavior changes. Hence, we investigated the effects of radiofrequency (RF) radiation on calcium binding proteins, reactive gliosis, and tumor genesis in mouse brain. Materials & Methods:Mice were exposed to radiofrequency radiation in the cage chamber with average specific absorption rate (SAR) of 1.6 W/kg and 4.0 W/Kg for one hour per day for five days. For histochemical studies, radiofrequency exposed brains were compared with sham control using calbindin D-28k antibody.Results:The immunoreactivity of calbindin D-28k, a marker for calcium homeostasis was found to increase in dose-response manner in hippocampus and cerebellar cortex.Conclusion:The short-term exposure to 835 MHz RF could induce disruption of calcium homeostasis and resulting neurobehavioral changes or brain tumor.

Perspectives on using a multiplex human kidney safety biomarker panel to detect cisplatin-induced tubular toxicity in male and female Cynomolgus monkeys

Multiplex biomarker panel assays would enable early de-risking of discovery compound related kidney safety liabilities. The objective of this study was to evaluate the usefulness of the Myriad RBM Human KidneyMAP (Multi-Analyte Profile)® v.1.0 panel to detect experimental nephrotoxicity in Cynomolgus monkeys following a single intravenous administration of cisplatin (2.5mg/kg). Urine samples were collected at baseline on day −2; at approximately 4hr post-dose on day 1; and on days 4, 9, 15 and/or 20. Blood samples were collected at predose on day −2; at 4hr post-dose on day 1; and on days 2, 5, 10 and/or 21. Changes in toxicokinetic and biochemistry parameters in plasma, qualitative/quantitative urinalysis parameters, and urinary kidney safety biomarkers were assessed. Kidney tissues were collected on days 2, 5, 10 and 21 for routine microscopy. Cisplatin-induced tubular alterations were characterized by acute and progressive cortical tubular degeneration/necrosis, regeneration, tubular dilation and proteinaceous cast in the absence of statistically significant changes in traditional plasma biochemistry and urinalysis parameters. When normalized to urinary creatinine, cisplatin-induced significant increases in urinary levels of kidney injury molecule 1 (females on day 4), increases in calbindin D28k (males and females on day 4), decreases in Tamm-Horsfall glycoprotein (males on days 1, 4 and 9), and increases in clusterin (females and males on days 15 and 20, respectively), when compared to concurrent controls. This study revealed the usefulness of the Human KidneyMAP® multiplex panel when measuring changes in urine-based biomarkers to reliably detect cisplatin-induced acute/progressive cortical tubular injury in male and female Cynomolgus monkeys.

Calcium-binding proteins expression in the septum and cingulate cortex of the adult guinea pig

For the first time this study demonstrates the distribution pattern and expression of three neuroanatomical markers: calbindin D28k (CB), calretinin (CR) and parvalbumin (PV) in topographically connected brain regions — the septum (SE) and the cingulate cortex (CC). The co-existence among calcium-binding proteins (CaBPs) was also examined. The study was conducted on the adult guinea pig with the use of immunohistochemical and molecular biological techniques. Among the studied CaBPs, which occurred in both examined brain regions at transcript and protein levels, CB was the most expressed in the SE, while CR in the CC. CR, unlike CB and PV, showed higher immunoreactivity in the superficial layers (II–III) of the CC than in the deep ones (V–VI). Most of CB and PV-positive perikarya were detected in the deep layers of the CC. Some CC neurons contained both CB and PV, suggesting cooperation between these CaBPs in the CC. Co-localization between CB and CR in the CC was not observed.

Expression of Calcium-Binding Proteins, Calbindin D28k and Calretinin, in the Frog Taste Receptor Structures

Considering that information on the expression of calcium-binding proteins (CaBPs) in different cells of the taste receptors is rather limited, we investigated the distribution of such proteins, calbindin D28k (CB) and calretinin (CR), in the taste disc (TD) of the frog Lithobates catesbeianus. Western blot analysis revealed that CB and CR are expressed in cells of the fungiform papillae. CB-immunoreactive (ir) and CR-ir cell somata were located in the middle layer of the TD. Most CB-ir and CR-ir cells possessed one rod-shaped apical process and one basal process; in some cells there were several extended basal processes. Apical processes of CR-ir cells were thinner than those of CB-ir units, and CR-ir nerve fibers were ramified in the lamina propria directly below the TD. Most CR-ir fiber branches surrounded the TD; however, some penetrated this region, with both types of branches approaching the surface. CB and CR immunoreactivities did not co-occur in TD cells. In the TDs examined, the number of CB-ir cells was significantly greater than that of CR-ir units. Our observations suggest that CB-ir and CR-ir cells in the frog TD correspond to type-II and type-III cells, respectively.

Expression of estrogen receptor β in hypothalamic stem cells

Abstract Neural stem cell activity at least partially accounts for the postweaning development of the sexually dimorphic nucleus of the preoptic area (SDN-POA) and estrogen selectively mobilizes neural stem cells in the 3rd ventricle stem cell niche (3VSCN). Here, we examined the expression of estrogen receptor β (ERβ) in the SDN-POA and the 3VSCN. A subset of cells within the SDN-POA--delineated with or without calbindin D28K (CB28)-immunoreactivity (ir)--exhibited ERβ-ir. The ependymal cells that expressed nestin within the 3VSCN also expressed ERβ. Interestingly, a few proliferating (Ki67 positive) cells within the 3VSCN and the hypothalamic parenchyma, including the SDN-POA, displayed ERβ-ir. In parallel, a subset of cells in the subventricular zone was double-labeled with nestin and ERβ or Ki67 and ERβ while the subgranular zone exhibited few such double-labeled cells. ERβ is expressed in hypothalamic stem cells that may regulate cell regenerative cycles.

Glutamine protects intestinal calcium absorption against oxidative stress and apoptosis

The aim of this study was to investigate whether glutamine (GLN) could block the inhibition of the intestinal Ca2+ absorption caused by menadione (MEN), and elucidate the underlying mechanisms. To do this, one-month old chicks were divided in four groups: 1) controls, 2) MEN treated, 3) GLN treated and 4) GLN treated before or after MEN treatment. Intestinal Ca2+ absorption as well as protein expression of molecules involved in the transcellular Ca2+ pathway were determined. Glutathione (GSH) and superoxide anion and activity of enzymes of the antioxidant system were evaluated. Apoptosis was measured by the TUNEL technique, the expression of FAS and FASL and the caspase-3 activity. A previous dose of 0.5gGLN/kg of b.w. was necessary to show its protector effect and a dose of 1g/kg of b.w. could restore the intestinal Ca2+ absorption after MEN treatment. GLN alone did not modify the protein expression of calbindin D28k and plasma membrane Ca2+-ATPase, but blocked the inhibitory effect of the quinone. GLN avoided changes in the intestinal redox state provoked by MEN such as a decrease in the GSH content, and increases in the superoxide anion and in the SOD and CAT activities. GLN abrogated apoptotic effects caused by MEN in intestinal mucosa, as indicated by the reduction of TUNEL (+) cells and the FAS/FASL/caspase-3 pathway. In conclusion, GLN could be an oral nutritional supplement to normalize the redox state and the proliferation/cell death ratio in the small intestine improving the intestinal Ca2+ absorption altered by oxidative stress.

Alteration of Interneuron Immunoreactivity and Autophagic Activity in Rat Hippocampus after Single High-Dose Whole-Brain Irradiation.

The effects of high dose gamma radiation on brain tissue are poorly understood, with both limited and major changes reported. The present study compared the effects of gamma irradiation on the expression of interneuron markers within the hippocampal cornu ammonis 1 (CA1) region with expression in control matched rats. This area was chosen for study because of its well-characterized circuitry. Male Sprague-Dawley rats were exposed to 60 Gy of whole brain gamma radiation and after 24 or 48 hours, the brains were removed, fixed and sectioned to quantitate expression of parvalbumin (PV), calbindin-D28K (CB), reelin, neuropeptide-Y (NPY), and somatostatin. All of these markers increased in expression over the first 48 hours, except NPY, which decreased. This provides novel information on changes in gene expression in the hippocampal interneurons following radiation. Staining for Beclin 1, a marker of autophagy, increased most strongly in the subgranular zone (SGZ) of the dentate gyrus (DG). Overall, the results are consistent with the hypothesis that increased intracellular calcium follows irradiation, leading to an increased expression of calcium binding proteins. Increased autophagy occurs in the neurogenic zone of the dentate hilus, consistent with reduced effective neurogenesis after irradiation.

Immunoreactivities of calbindin‑D28k, calretinin and parvalbumin in the somatosensory cortex of rodents during normal aging.

Calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV), which regulate cytosolic free Ca2+ concentrations in neurons, are chemically expressed in γ-aminobutyric acid (GABA)ergic neurons that regulate the degree of glutamatergic excitation and output of projection neurons. The present study investigated age-associated differences in CB, CR and PV immunoreactivities in the somatosensory cortex in three species (mice, rats and gerbils) of young (1 month), adult (6 months) and aged (24 months) rodents, using immunohistochemistry and western blotting. Abundant CB-immunoreactive neurons were distributed in layers II and III, and age-associated alterations in their number were different according to the species. CR-immunoreactive neurons were not abundant in all layers; however, the number of CR-immunoreactive neurons was the highest in all adult species. Many PV-immunoreactive neurons were identified in all layers, particularly in layers II and III, and they increased in all layers with age in all species. The present study demonstrated that the distribution pattern of CB-, CR- and PV-containing neurons in the somatosensory cortex were apparently altered in number with normal aging, and that CB and CR exhibited a tendency to decrease in aged rodents, whereas PV tended to increase with age. These results indicate that CB, CR and PV are markedly altered in the somatosensory cortex, and this change may be associated with normal aging. These findings may aid the elucidation of the mechanisms of aging and geriatric disease.

Neonatal Inhibition of DNA Methylation Alters Cell Phenotype in Sexually Dimorphic Regions of the Mouse Brain.

Many of the best-studied neural sex differences relate to differences in cell number and are due to the hormonal control of developmental cell death. However, several prominent neural sex differences persist even if cell death is eliminated. We hypothesized that these may reflect cell phenotype "decisions" that depend on epigenetic mechanisms, such as DNA methylation. To test this, we treated newborn mice with the DNA methyltransferase (DNMT) inhibitor zebularine, or vehicle, and examined two sexually dimorphic markers at weaning. As expected, control males had more cells immunoreactive for calbindin-D28k (CALB) in the medial preoptic area (mPOA) and fewer cells immunoreactive for estrogen receptor α (ERα) in the ventrolateral portion of the ventromedial nucleus of the hypothalamus (VMHvl) and the mPOA than did females. Neonatal DNMT inhibition markedly increased CALB cell number in both sexes and ERα cell density in males; as a result, the sex differences in ERα in the VMHvl and mPOA were completely eliminated in zebularine-treated animals. Zebularine treatment did not affect developmental cell death or the total density of Nissl-stained cells at weaning. Thus, a neonatal disruption of DNA methylation apparently has long-term effects on the proportion of cells expressing CALB and ERα, and some of these effects are sex specific. We also found that sex differences in CALB in the mPOA and ERα in the VMHvl persist in mice with a neuron-specific depletion of either Dnmt1 or Dnmt3b, indicating that neither DNMT alone is likely to be required for the sexually dimorphic expression of these markers.

Moxd1 Is a Marker for Sexual Dimorphism in the Medial Preoptic Area, Bed Nucleus of the Stria Terminalis and Medial Amygdala.

The brain shows various sex differences in its structures. Various mammalian species exhibit sex differences in the sexually dimorphic nucleus of the preoptic area (SDN-POA) and parts of the extended amygdala such as the principal nucleus of the bed nucleus of the stria terminalis (BNSTpr) and posterodorsal part of the medial amygdala (MePD). The SDN-POA and BNSTpr are male-biased sexually dimorphic nuclei, and characterized by the expression of calbindin D-28K (calbindin 1). However, calbindin-immunoreactive cells are not restricted to the SDN-POA, but widely distributed outside of the SDN-POA. To find genes that are more specific to sexually dimorphic nuclei, we selected candidate genes by searching the Allen brain atlas and examined the detailed expressions of the candidate genes using in situ hybridization. We found that the strong expression of monooxygenase DBH-like 1 (Moxd1) was restricted to the SDN-POA, BNSTpr and MePD. The numbers of Moxd1-positive cells in the SDN-POA, BNSTpr and MePD in male mice were larger than those in female mice. Most of the Moxd1-positive cells in the SDN-POA and BNSTpr expressed calbindin. Neonatal castration of male mice reduced the number of Moxd1-positive cells in the SDN-POA, whereas gonadectomy in adulthood did not change the expression of the Moxd1 gene in the SDN-POA in both sexes. These results suggest that the Moxd1 gene is a suitable marker for sexual dimorphic nuclei in the POA, BNST and amygdala, which enables us to manipulate sexually dimorphic neurons to examine their roles in sex-biased physiology and behaviors.

A Novel Method for Constructing Histological Section Datasets of the Basal Ganglia in Digitized Human Brain.

To investigate the construction of the histological section datasets in the basal ganglia of digitized human brain to provide a reference for the meso-level histological data acquisition. A fresh adult brain from a cadaver with no neurological disease was selected, and tissue blocks of the basal ganglia in the right hemisphere was extracted using the visualization method, followed by pretreatments including gradient dehydrating, gelatin-embedding and setting of calibration points. And then the tissue blocks was cryosectioned into 60-μm-thick coronal sections and the sectional images were captured simultaneously by a digital camera at a fixed position. Two series of sections (one section out of ten) were Nissl-stained with Toluidine blue and immunostained with the calbindin D-28K, respectively. Stained sections were digitized by a high resolution scanner. After alignment and registration, contours of nuclei and different nucleic function divisions in the digital images of stained sections were identified, and then were segmented and labeled using software exploited by ourselves. Datasets of one set of registrated serial sectional images and two sets of registrated histochemically stained images in basal ganglia area were obtained, which provide a histological reference for the neurosurgery and diagnostic imaging. a systematic method of cutting, slicing, staining, data acquisition and image registration of large tissue blocks was established, providing a reference for histological data acquisition on the digital human. Anat Rec, 300:1011-1021, 2017. © 2016 Wiley Periodicals, Inc.

Leukemia inhibitory factor impairs structural and neurochemical development of rat visual cortex in vivo.

Minipump infusions into visual cortex in vivo at the onset of the critical period have revealed that the proinflammatory cytokine leukemia inhibitory factor (LIF) delays the maturation of thalamocortical projection neurons of the lateral geniculate nucleus, and tecto-thalamic projection neurons of the superior colliculus, and cortical layer IV spiny stellates and layer VI pyramidal neurons. Here, we report that P12-20 LIF infusion inhibits somatic maturation of pyramidal neurons and of all interneuron types in vivo. Likewise, DIV 12-20 LIF treatment in organotypic cultures prevents somatic growth GABA-ergic neurons. Further, while NPY expression is increased in the LIF-infused hemispheres, the expression of parvalbumin mRNA and protein, Kv3.1 mRNA, calbindin D-28k protein, and GAD-65 mRNA, but not of GAD-67 mRNA or calretinin protein is substantially reduced. Also, LIF treatment decreases parvalbumin, Kv3.1, Kv3.2 and GAD-65, but not GAD-67 mRNA expression in OTC. Developing cortical neurons are known to depend on neurotrophins. Indeed, LIF alters neurotrophin mRNA expression, and prevents the growth promoting action of neurotophin-4 in GABA-ergic neurons. The results imply that LIF, by altering neurotrophin expression and/or signaling, could counteract neurotrophin-dependent growth and neurochemical differentiation of cortical neurons.

Influence of oral administration of HMB to pregnant dams on calbindin expression in the dentate gyrus of the hippocampus during postnatal development in spiny mice offspring

The aim of the study was to investigate the morphology, density and immunostaining intensity of calbindin (CB)-positive neurons of dentate gyrus (DG) in new-born (P0) and 21-day-old (P21) male Acomys cahirinus mice from dams receiving β-hydroxy-β-methylbutyrate (HMB) during pregnancy. Different substances administrated to pregnant dams may affect the calcium ion homeostasis which is crucial for the proper brain development of their offspring. DG with hilus (H) plays an important role in memory and learning processes. Calcium levels in DG are regulated by buffering proteins like calbindin D28k (CB). Experimental dams were orally treated with HMB at a dose of 0.2g/kg b.w. Half of new-born animals were euthanised after birth and the rest after the 21st day of life. The brains were dissected and embedded in paraffin blocks using a routine histological technique. In order to demonstrate CB protein expression an immunohistochemical peroxidase-antiperoxidase reaction was conducted. The results of the study did not reveal important morphological alterations. There were no statistically significant changes in the density of the studied cells either in P0 and P21 animals. However, the authors have demonstrated a statistically significant increase of the average CB-immunostaining intensity in nuclei and cytoplasm in both age groups. It may be a result of a compensation effect to alterations that occurred under the influence of HMB. On the basis of the conducted research, it may be assumed that HMB activity in DG may provide long-term consequences.

Neuroprotective effects of ischemic preconditioning on hippocampal CA1 pyramidal neurons through maintaining calbindin D28k immunoreactivity following subsequent transient cerebral ischemia.

Ischemic preconditioning elicited by a non-fatal brief occlusion of blood flow has been applied for an experimental therapeutic strategy against a subsequent fatal ischemic insult. In this study, we investigated the neuroprotective effects of ischemic preconditioning (2-minute transient cerebral ischemia) on calbindin D28k immunoreactivity in the gerbil hippocampal CA1 area following a subsequent fatal transient ischemic insult (5-minute transient cerebral ischemia). A large number of pyramidal neurons in the hippocampal CA1 area died 4 days after 5-minute transient cerebral ischemia. Ischemic preconditioning reduced the death of pyramidal neurons in the hippocampal CA1 area. Calbindin D28k immunoreactivity was greatly attenuated at 2 days after 5-minute transient cerebral ischemia and it was hardly detected at 5 days post-ischemia. Ischemic preconditioning maintained calbindin D28k immunoreactivity after transient cerebral ischemia. These findings suggest that ischemic preconditioning can attenuate transient cerebral ischemia-caused damage to the pyramidal neurons in the hippocampal CA1 area through maintaining calbindin D28k immunoreactivity.

Effect of hyperthermia on calbindin-D 28k immunoreactivity in the hippocampal formation following transient global cerebral ischemia in gerbils.

Calbindin D-28K (CB), a Ca2+-binding protein, maintains Ca2+ homeostasis and protects neurons against various insults. Hyperthermia can exacerbate brain damage produced by ischemic insults. However, little is reported about the role of CB in the brain under hyperthermic condition during ischemic insults. We investigated the effects of transient global cerebral ischemia on CB immunoreactivity as well as neuronal damage in the hippocampal formation under hyperthermic condition using immunohistochemistry for neuronal nuclei (NeuN) and CB, and Fluoro-Jade B histofluorescence staining in gerbils. Hyperthermia (39.5 ± 0.2°C) was induced for 30 minutes before and during transient ischemia. Hyperthermic ischemia resulted in neuronal damage/death in the pyramidal layer of CA1–3 area and in the polymorphic layer of the dentate gyrus at 1, 2, 5 days after ischemia. In addition, hyperthermic ischemia significantly decreaced CB immunoreactivity in damaged or dying neurons at 1, 2, 5 days after ischemia. In brief, hyperthermic condition produced more extensive and severer neuronal damage/death, and reduced CB immunoreactivity in the hippocampus following transient global cerebral ischemia. Present findings indicate that the degree of reduced CB immunoreactivity might be related with various neuronal damage/death overtime and corresponding areas after ischemic insults.

Development of Calbindin- and Calretinin-Immunopositive Neurons in the Enteric Ganglia of Rats.

Calbindin D28K (CB) and calretinin (CR) are the members of the EF-hand family of calcium-binding proteins that are expressed in neurons and nerve fibers of the enteric nervous system. CB and CR are expressed differentially in neuronal subpopulations throughout the central and peripheral nervous systems and their expression has been used to selectively target specific cell types and isolate neuronal networks. The present study presents an immunohistochemical analysis of CB and CR in the enteric ganglia of small intestine in rats of different ages (newborn, 10-day-old, 20-day-old, 30-day-old, 60-day-old, 1-year-old, and 2-year-old). The data obtained suggest a number of age-dependent changes in CB and CR expression in the myenteric and submucous plexuses. In the myenteric plexus, the lowest percentage of CB-immunoreactive (IR) and CR-IR neurons was observed at birth, after which the number of IR cells increased in the first 10days of life. In the submucous plexus, CB-IR and CR-IR neurons were observed from 10-day-old onwards. The percentage of CR-IR and CB-IR neurons increased in the first 2 months and in the first 20days, respectively. In all animals, the majority of the IR neurons colocalized CR and CB. From the moment of birth, the mean of the cross-sectional area of the CB-IR and CR-IR neuronal profiles was larger than that of CB- and CR-negative cells.

Distribution and chemical coding of sensory neurons innervating the skin of the porcine hindlimb

The aim of the present study was to establish the origin and chemical phenotyping of neurons involved in skin innervation of the porcine hind leg. The dorsal root ganglia (DRGs) of the lumbar (L4–L6) and sacral (S1–S3) spinal nerves were visualized using the fluorescent tracer Fast Blue (FB). The morphometric analysis of FB-positive (FB+)neurons showed that in the L4, L5, S1 and S2 DRGs, the small-sized perikarya constituted the major population, whereas in the L6 and S3 DRGs the medium-sized cells made up the major population. In all these ganglia, large-sized FB+ perikarya constituted only a small percentage of all FB+ neurons. Immunohistochemistry revealed that small- and medium-sized FB+ perikarya contained sensory markers such as: substance P (SP), calcitonin gene related peptide (CGRP) and galanin (GAL); as well as various other factors such as somatostatin (SOM), calbindin-D28k (CB), pituitary adenylate cyclase-activating polypeptide (PACAP) and neuronal nitric oxide synthase (nNOS). Meanwhile large-sized FB+ perikarya usually expressed SP, CGRP or PACAP. In the lumbar DRGs, some large cells also contained SOM and CB. Double-labeling immunohistochemistry showed that SP-positive neurons co-expressed CGRP, GAL or PACAP; while PACAP-positive cells co-expressed GAL or nNOS. Neurons stained for SOM were also immunoreactive for CB or GAL, while neurons stained for nNOS were also immunoreactive for GAL. In conclusion, the present data has indicated that the distribution and chemical phenotyping of the porcine skin-projecting neurons are different within DRGs of the lumbar (forming a femoral nerve) and sacral (forming a sciatic nerve) spinal nerves.

Alpha-synuclein aggregates are excluded from calbindin-D28k-positive neurons in dementia with Lewy bodies and a unilateral rotenone mouse model.

α-Synuclein (α-syn) aggregates (Lewy bodies) in Dementia with Lewy Bodies (DLB) may be associated with disturbed calcium homeostasis and oxidative stress. We investigated the interplay between α-syn aggregation, expression of the calbindin-D28k (CB) neuronal calcium-buffering protein and oxidative stress, combining immunofluorescence double labelling and Western analysis, and examining DLB and normal human cases and a unilateral oxidative stress lesion model of α-syn disease (rotenone mouse). DLB cases showed a greater proportion of CB+ cells in affected brain regions compared to normal cases with Lewy bodies largely present in CB- neurons and virtually undetected in CB+ neurons. The unilateral rotenone-lesioned mouse model showed a greater proportion of CB+ cells and α-syn aggregates within the lesioned hemisphere than the control hemisphere, especially proximal to the lesion site, and α-syn inclusions occurred primarily in CB- cells and were almost completely absent in CB+ cells. Consistent with the immunofluorescence data, Western analysis showed the total CB level was 25% higher in lesioned compared to control hemisphere in aged animals that are more sensitive to lesion and 20% higher in aged compared to young mice in lesioned hemisphere, but not significantly different between young and aged in the control hemisphere. Taken together, the findings show α-syn aggregation is excluded from CB+ neurons, although the increased sensitivity of aged animals to lesion was not related to differential CB expression.

A comparative study of sex difference in calbindin neurons among mice, musk shrews, and Japanese quails

The medial preoptic nucleus (MPN) and the bed nucleus of the stria terminalis (BNST) of mice contain sexually dimorphic nuclei (SDNs) that are larger and have more neurons expressing calbindin D-28K (CB), a calcium-binding protein, in males than females. However, it is largely unknown whether such SDNs exist in species other than rodents. In this study, we performed an immunohistochemical study of CB in the MPN and BNST of musk shrews and Japanese quails to examine the existence of homologs of SDNs in mice. Like mice, musk shrews had a SDN exhibiting male-biased sex differences in volume and CB-immunoreactive (ir) cell number in the MPN. The BNST of musk shrews also contained a male-biased SDN, but consisted of non-CB neurons. The paratenial thalamic nucleus of musk shrews, but not mice, had more CB-ir cells in males than females. In Japanese quails of both sexes, CB-ir cells in the MPN and BNST were extremely small in number and did not cluster. These results suggest that the distribution of CB neurons differs among these species. Musk shrews may have a homolog of the SDN composed of CB neurons in the MPN of mice.