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Zhang B, Li L, Tang X, Zeng J, Song Y, Hou Z, Ma T, Afewerky HK, Li H, Lu Y, He A, Li X. Distribution Patterns of Subgroups of Inhibitory Neurons Divided by Calbindin 1. Mol Neurobiol 2023; 60:7285-7296. [PMID: 37548854 DOI: 10.1007/s12035-023-03542-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/25/2023] [Indexed: 08/08/2023]
Abstract
The inhibitory neurons in the brain play an essential role in neural network firing patterns by releasing γ-aminobutyric acid (GABA) as the neurotransmitter. In the mouse brain, based on the protein molecular markers, inhibitory neurons are usually to be divided into three non-overlapping groups: parvalbumin (PV), neuropeptide somatostatin (SST), and vasoactive intestinal peptide (VIP)-expressing neurons. Each neuronal group exhibited unique properties in molecule, electrophysiology, circuitry, and function. Calbindin 1 (Calb1), a ubiquitous calcium-binding protein, often acts as a "divider" in excitatory neuronal classification. Based on Calb1 expression, the excitatory neurons from the same brain region can be classified into two subgroups with distinct properties. Besides excitatory neurons, Calb1 also expresses in part of inhibitory neurons. But, to date, little research focused on the intersectional relationship between inhibitory neuronal subtypes and Calb1. In this study, we genetically targeted Calb1-expression (Calb1+) and Calb1-lacking (Calb1-) subgroups of PV and SST neurons throughout the mouse brain by flexibly crossing transgenic mice relying on multi-recombinant systems, and the distribution patterns and electrophysiological properties of each subgroup were further demonstrated. Thus, this study provided novel insights and strategies into inhibitory neuronal classification.
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Affiliation(s)
- Bing Zhang
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lanfang Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiaomei Tang
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jinyu Zeng
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yige Song
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Zhenye Hou
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Tian Ma
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Henok Kessete Afewerky
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hao Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Youming Lu
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Physiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Aodi He
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Department of Anatomy, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Xinyan Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Department of Anatomy, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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2
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Eisner D, Neher E, Taschenberger H, Smith G. Physiology of intracellular calcium buffering. Physiol Rev 2023; 103:2767-2845. [PMID: 37326298 DOI: 10.1152/physrev.00042.2022] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/08/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023] Open
Abstract
Calcium signaling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
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Affiliation(s)
- David Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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3
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Wender M, Bornschein G, Brachtendorf S, Hallermann S, Eilers J, Schmidt H. Ca v2.2 Channels Sustain Vesicle Recruitment at a Mature Glutamatergic Synapse. J Neurosci 2023; 43:4005-4018. [PMID: 37185239 PMCID: PMC10255130 DOI: 10.1523/jneurosci.1279-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 05/17/2023] Open
Abstract
The composition of voltage-gated Ca2+ channel (Cav) subtypes that gate action potential (AP)-evoked release changes during the development of mammalian CNS synapses. Cav2.2 and Cav2.3 lose their function in gating-evoked release during postnatal synapse maturation. In mature boutons, Cav2.1 currents provide the almost exclusive trigger for evoked release, and Cav2.3 currents are required for the induction of presynaptic long-term potentiation. However, the functional significance of Cav2.2 remained elusive in mature boutons, although they remain present at active zones and continue contributing significantly to presynaptic Ca2+ influx. Here, we addressed the functional significance of Cav2.2 and Cav2.3 at mature parallel-fiber (PF) to Purkinje neuron synapses of mice of either sex. These synapses are known to exhibit the corresponding developmental Cav subtype changes in gating release. We addressed two hypotheses, namely that Cav2.2 and Cav2.3 are involved in triggering spontaneous glutamate release and that they are engaged in vesicle recruitment during repetitive evoked release. We found that spontaneous miniature release is Ca2+ dependent. However, experiments with Cav subtype-specific blockers excluded the spontaneous opening of Cavs as the Ca2+ source for spontaneous glutamate release. Thus, neither Cav2.2 nor Cav2.3 controls spontaneous release from PF boutons. Furthermore, vesicle recruitment during brief bursts of APs was also independent of Ca2+ influx through Cav2.2 and Cav2.3. However, Cav2.2, but not Cav2.3, currents significantly boosted vesicle recruitment during sustained high-frequency synaptic transmission. Thus, in mature PF boutons Cav2.2 channels are specifically required to sustain synaptic transmission during prolonged neuronal activity.SIGNIFICANCE STATEMENT At young CNS synapses, action potential-evoked release is gated via three subtypes of voltage-gated Ca2+ channels: Cav2.1, Cav2.2, and Cav2.3. During postnatal maturation, Cav2.2 and Cav2.3 lose their function in gating evoked release, such that at mature synapses Cav2.1 provides the almost exclusive source for triggering evoked release. Cav2.3 currents are required for the induction of presynaptic long-term potentiation. However, the function of the still abundant Cav2.2 in mature boutons remained largely elusive. Here, we studied mature cerebellar parallel-fiber synapses and found that Cav2.2 does not control spontaneous release. However, Ca2+ influx through Cav2.2 significantly boosted vesicle recruitment during trains of action potentials. Thus, Cav2.2 in mature parallel-fiber boutons participate in sustaining synaptic transmission during prolonged activity.
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Affiliation(s)
- Magdalena Wender
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Grit Bornschein
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Simone Brachtendorf
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Stefan Hallermann
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Jens Eilers
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Hartmut Schmidt
- Carl Ludwig Institute for Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
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Chen Q, Shen L, Li S. Emerging role of inositol monophosphatase in cancer. Biomed Pharmacother 2023; 161:114442. [PMID: 36841024 DOI: 10.1016/j.biopha.2023.114442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 02/27/2023] Open
Abstract
Inositol monophosphatase (IMPase) is an enzyme with two homologs-IMPA1 and IMPA2-that is responsible for dephosphorylating myo-inositol monophosphate to generate myo-inositol. IMPase has been extensively studied in neuropsychiatric diseases and is regarded as a susceptibility gene. Recently, emerging evidence has implied that IMPase is linked to cancer development and progression and correlates with patient survival outcomes. Interestingly, whether it acts as a tumor-promoter or tumor-suppressor is inconsistent among different research studies. In this review, we summarize the latest findings on IMPase in cancer, focusing on exploring the underlying mechanisms for its pro- and anticancer roles. In addition, we discuss the potential methods of IMPase regulation in cancer cells and the possible approaches for IMPase intervention in clinical practice.
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Affiliation(s)
- Qian Chen
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China; National Clinical Research Center for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Liangfang Shen
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China; National Clinical Research Center for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Shan Li
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China; National Clinical Research Center for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China.
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5
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Hagen-Lillevik S, Johnson J, Siddiqi A, Persinger J, Hale G, Lai K. Harnessing the Power of Purple Sweet Potato Color and Myo-Inositol to Treat Classic Galactosemia. Int J Mol Sci 2022; 23:8654. [PMID: 35955788 PMCID: PMC9369367 DOI: 10.3390/ijms23158654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 01/25/2023] Open
Abstract
Classic Galactosemia (CG) is a devastating inborn error of the metabolism caused by mutations in the GALT gene encoding the enzyme galactose-1 phosphate uridylyltransferase in galactose metabolism. Severe complications of CG include neurological impairments, growth restriction, cognitive delays, and, for most females, primary ovarian insufficiency. The absence of the GALT enzyme leads to an accumulation of aberrant galactose metabolites, which are assumed to be responsible for the sequelae. There is no treatment besides the restriction of dietary galactose, which does not halt the development of the complications; thus, additional treatments are sorely needed. Supplements have been used in other inborn errors of metabolism but are not part of the therapeutic regimen for CG. The goal of this study was to test two generally recognized as safe supplements (purple sweet potato color (PSPC) and myo-inositol (MI)) that may impact cellular pathways contributing to the complications in CG. Our group uses a GalT gene-trapped mouse model to study the pathophysiology in CG, which phenocopy many of the complications. Here we report the ability of PSPC to ameliorate dysregulation in the ovary, brain, and liver of our mutant mice as well as positive results of MI supplementation in the ovary and brain.
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Affiliation(s)
- Synneva Hagen-Lillevik
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84108, USA
| | - Joshua Johnson
- Division of Reproductive Sciences, Aurora, CO 80045, USA
- Division of Reproductive Endocrinology and Infertility, Aurora, CO 80045, USA
- Department of Obstetrics and Gynecology, Aurora, CO 80045, USA
| | - Anwer Siddiqi
- College of Medicine, University of Florida, Jacksonville, FL 32209, USA
| | - Jes Persinger
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80302, USA
| | - Gillian Hale
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Kent Lai
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84108, USA
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6
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Noble JW, Atack JR. Exploring Calbindin-IMPase fusion proteins structure and activity. Biochem Biophys Rep 2022; 30:101266. [PMID: 35540435 PMCID: PMC9079241 DOI: 10.1016/j.bbrep.2022.101266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 03/23/2022] [Accepted: 04/20/2022] [Indexed: 11/09/2022] Open
Abstract
Calbindin-D28k is a calcium binding protein that is highly expressed in the mammalian central nervous system. It has been reported that calbindin-D28k binds to and increases the activity of inositol Monophosphatase (IMPase). This is an enzyme that is involved in the homeostasis of the Inositol trisphosphate signalling cascade by catalysing the final dephosphorylation of inositol and has been implicated in the therapeutic mechanism of lithium treatment of bipolar disorder. Previously studies have shown that calbindin-D28k can increase IMPase activity by up to 250 hundred-fold. A preliminary in silico model was proposed for the interaction. Here, we aimed at exploring the shape and properties of the calbindin-IMPase complex to gain new insights on this biologically important interaction. We created several fusion constructs of calbindin-D28k and IMPase, connected by flexible amino acid linkers of different lengths and orientations to fuse the termini of the two proteins together. The resulting fusion proteins have activities 200%–400% higher the isolated wild-type IMPase. The constructs were characterized by small angle X-ray scattering to gain information on the overall shape of the complexes and validate the previous model. The fusion proteins form a V-shaped, elongated and less compact complex as compared to the model. Our results shed new light into this protein-protein interaction. The interaction between calbindin-D28k and the enzyme IMPase is studies using fusion proteins. The fusion proteins have activities 200%–400% higher than wild-type IMPase. The calbindin-D28k and the enzyme IMPase fusion proteins have a V-shaped structure.
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7
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George B, Szilagyi JT, Joy MS, Aleksunes LM. Regulation of renal calbindin expression during cisplatin‐induced kidney injury. J Biochem Mol Toxicol 2022; 36:e23068. [DOI: 10.1002/jbt.23068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 11/20/2021] [Accepted: 01/04/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Blessy George
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy Rutgers University Piscataway New Jersey USA
| | - John T. Szilagyi
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy Rutgers University Piscataway New Jersey USA
| | - Melanie S. Joy
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences University of Colorado Aurora Colorado USA
- Division of Developmental Therapeutics, Cancer Center University of Colorado Aurora Colorado USA
- Division of Renal Diseases and Hypertension University of Colorado School of Medicine Aurora Colorado USA
| | - Lauren M. Aleksunes
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy Rutgers University Piscataway New Jersey USA
- Division of Toxicology, Environmental and Occupational Health Sciences Institute Rutgers University Piscataway New Jersey USA
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8
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Attaai AH, Noreldin AE, Abdel-Maksoud FM, Hussein MT. An updated investigation on the dromedary camel cerebellum (Camelus dromedarius) with special insight into the distribution of calcium-binding proteins. Sci Rep 2020; 10:21157. [PMID: 33273572 PMCID: PMC7713137 DOI: 10.1038/s41598-020-78192-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 11/12/2020] [Indexed: 01/07/2023] Open
Abstract
Studying the cerebella of different animals is important to expand the knowledge about the cerebellum. Studying the camel cerebellum was neglected even though the recent research in the middle east and Asia. Therefore, the present study was designed to achieve a detailed description of the morphology and the cellular organization of the camel cerebellum. Because of the high importance of the calcium ions as a necessary moderator the current work also aimed to investigate the distribution of calcium binding proteins (CaBP) such as calbindin D-28K (CB), parvalbumin (PV) and calretinin (CR) in different cerebellar cells including the non-traditional neurons. The architecture of camel cerebellum, as different mammals, consists of the medulla and three layered-cortex. According to our observation the cells in the granular layer were not crowded and many spaces were observed. CB expression was the highest by Purkinje cells including their dendritic arborization. In addition to its expression by the inhibitory interneurons (basket, stellate and Golgi neurons), it is also expressed by the excitatory granule cells. PV was expressed by Purkinje cells, including their primary arborization, and by the molecular layer cells. CR immunoreactivity (-ir) was obvious in almost all cell layers with varying degrees, however a weak or any expression by the Purkinje cells. The molecular layer cells and the Golgi and the non traditional large neurons of the granular layer showed the strongest CR-ir. Granule neurons showed moderate immunoreactivity for CB and CR. In conclusion, the results of the current study achieved a complete map for the neurochemical organization of CaBP expression and distribution by different cells in the camel cerebellum.
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Affiliation(s)
- Abdelraheim H Attaai
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71526, Assiut, Egypt
| | - Ahmed E Noreldin
- Department of Histology and Cytology, Faculty of Veterinary Medicine, Damanhour University, 22511, Damanhour, Egypt
| | - Fatma M Abdel-Maksoud
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71526, Assiut, Egypt.
| | - Manal T Hussein
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, 71526, Assiut, Egypt
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9
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Mergenthal A, Bouteiller JMC, Yu GJ, Berger TW. A Computational Model of the Cholinergic Modulation of CA1 Pyramidal Cell Activity. Front Comput Neurosci 2020; 14:75. [PMID: 33013341 PMCID: PMC7509450 DOI: 10.3389/fncom.2020.00075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 07/17/2020] [Indexed: 01/02/2023] Open
Abstract
Dysfunction in cholinergic modulation has been linked to a variety of cognitive disorders including Alzheimer's disease. The important role of this neurotransmitter has been explored in a variety of experiments, yet many questions remain unanswered about the contribution of cholinergic modulation to healthy hippocampal function. To address this question, we have developed a model of CA1 pyramidal neuron that takes into consideration muscarinic receptor activation in response to changes in extracellular concentration of acetylcholine and its effects on cellular excitability and downstream intracellular calcium dynamics. This model incorporates a variety of molecular agents to accurately simulate several processes heretofore ignored in computational modeling of CA1 pyramidal neurons. These processes include the inhibition of ionic channels by phospholipid depletion along with the release of calcium from intracellular stores (i.e., the endoplasmic reticulum). This paper describes the model and the methods used to calibrate its behavior to match experimental results. The result of this work is a compartmental model with calibrated mechanisms for simulating the intracellular calcium dynamics of CA1 pyramidal cells with a focus on those related to release from calcium stores in the endoplasmic reticulum. From this model we also make various predictions for how the inhibitory and excitatory responses to cholinergic modulation vary with agonist concentration. This model expands the capabilities of CA1 pyramidal cell models through the explicit modeling of molecular interactions involved in healthy cognitive function and disease. Through this expanded model we come closer to simulating these diseases and gaining the knowledge required to develop novel treatments.
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Affiliation(s)
- Adam Mergenthal
- Biomedical Engineering Department, Center for Neural Engineering, University of Southern California, Los Angeles, CA, United States
| | - Jean-Marie C Bouteiller
- Biomedical Engineering Department, Center for Neural Engineering, University of Southern California, Los Angeles, CA, United States
| | - Gene J Yu
- Biomedical Engineering Department, Center for Neural Engineering, University of Southern California, Los Angeles, CA, United States
| | - Theodore W Berger
- Biomedical Engineering Department, Center for Neural Engineering, University of Southern California, Los Angeles, CA, United States
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Schwaller B. Cytosolic Ca 2+ Buffers Are Inherently Ca 2+ Signal Modulators. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035543. [PMID: 31308146 DOI: 10.1101/cshperspect.a035543] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
For precisely regulating intracellular Ca2+ signals in a time- and space-dependent manner, cells make use of various components of the "Ca2+ signaling toolkit," including Ca2+ entry and Ca2+ extrusion systems. A class of cytosolic Ca2+-binding proteins termed Ca2+ buffers serves as modulators of such, mostly short-lived Ca2+ signals. Prototypical Ca2+ buffers include parvalbumins (α and β isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Although initially considered to function as pure Ca2+ buffers, that is, as intracellular Ca2+ signal modulators controlling the shape (amplitude, decay, spread) of Ca2+ signals, evidence has accumulated that calbindin-D28k and calretinin have additional Ca2+ sensor functions. These other functions are brought about by direct interactions with target proteins, thereby modulating their targets' function/activity. Dysregulation of Ca2+ buffer expression is associated with several neurologic/neurodevelopmental disorders including autism spectrum disorder (ASD) and schizophrenia. In some cases, the presence of these proteins is presumed to confer a neuroprotective effect, as evidenced in animal models of Parkinson's or Alzheimer's disease.
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Affiliation(s)
- Beat Schwaller
- Department of Anatomy, Section of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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11
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Quantitation and Simulation of Single Action Potential-Evoked Ca 2+ Signals in CA1 Pyramidal Neuron Presynaptic Terminals. eNeuro 2019; 6:ENEURO.0343-19.2019. [PMID: 31551250 PMCID: PMC6800293 DOI: 10.1523/eneuro.0343-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 01/07/2023] Open
Abstract
Presynaptic Ca2+ evokes exocytosis, endocytosis, and synaptic plasticity. However, Ca2+ flux and interactions at presynaptic molecular targets are difficult to quantify because fluorescence imaging has limited resolution. In rats of either sex, we measured single varicosity presynaptic Ca2+ using Ca2+ dyes as buffers, and constructed models of Ca2+ dispersal. Action potentials evoked Ca2+ transients with little variation when measured with low-affinity dye (peak amplitude 789 ± 39 nM, within 2 ms of stimulation; decay times, 119 ± 10 ms). Endogenous Ca2+ buffering capacity, action potential-evoked free [Ca2+]i, and total Ca2+ amounts entering terminals were determined using Ca2+ dyes as buffers. These data constrained Monte Carlo (MCell) simulations of Ca2+ entry, buffering, and removal. Simulations of experimentally-determined Ca2+ fluxes, buffered by simulated calbindin28K well fit data, and were consistent with clustered Ca2+ entry followed within 4 ms by diffusion throughout the varicosity. Repetitive stimulation caused free varicosity Ca2+ to sum. However, simulated in nanometer domains, its removal by pumps and buffering was negligible, while local diffusion dominated. Thus, Ca2+ within tens of nanometers of entry, did not accumulate. A model of synaptotagmin1 (syt1)-Ca2+ binding indicates that even with 10 µM free varicosity evoked Ca2+, syt1 must be within tens of nanometers of channels to ensure occupation of all its Ca2+-binding sites. Repetitive stimulation, evoking short-term synaptic enhancement, does not modify probabilities of Ca2+ fully occupying syt1’s C2 domains, suggesting that enhancement is not mediated by Ca2+-syt1 interactions. We conclude that at spatiotemporal scales of fusion machines, Ca2+ necessary for their activation is diffusion dominated.
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Brimblecombe KR, Vietti-Michelina S, Platt NJ, Kastli R, Hnieno A, Gracie CJ, Cragg SJ. Calbindin-D28K Limits Dopamine Release in Ventral but Not Dorsal Striatum by Regulating Ca 2+ Availability and Dopamine Transporter Function. ACS Chem Neurosci 2019; 10:3419-3426. [PMID: 31361457 PMCID: PMC6706870 DOI: 10.1021/acschemneuro.9b00325] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
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The
calcium-binding protein calbindin-D28K, or calb1, is expressed
at higher levels by dopamine (DA) neurons originating in the ventral
tegmental area (VTA) than in the adjacent substantia nigra pars compacta
(SNc). Calb1 has received attention for a potential role in neuroprotection
in Parkinson’s disease. The underlying physiological roles
for calb1 are incompletely understood. We used cre-loxP technology
to knock down calb1 in mouse DA neurons to test whether calb1 governs
axonal release of DA in the striatum, detected using fast-scan cyclic
voltammetry ex vivo. In the ventral but not dorsal striatum, calb1
knockdown elevated DA release and modified the spatiotemporal coupling
of Ca2+ entry to DA release. Furthermore, calb1 knockdown
enhanced DA uptake but attenuated the impact of DA transporter (DAT)
inhibition by cocaine on underlying DA release. These data reveal
that calb1 acts through a range of mechanisms underpinning both DA
release and uptake to limit DA transmission in the ventral but not
dorsal striatum.
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Affiliation(s)
- Katherine R. Brimblecombe
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
- Oxford Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Stefania Vietti-Michelina
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Nicola J. Platt
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Rahel Kastli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Ahmad Hnieno
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Caitlin J. Gracie
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Stephanie J. Cragg
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
- Oxford Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3PT, United Kingdom
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13
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Wan L, Xu K, Chen Z, Tang B, Jiang H. Roles of Post-translational Modifications in Spinocerebellar Ataxias. Front Cell Neurosci 2018; 12:290. [PMID: 30283301 PMCID: PMC6156280 DOI: 10.3389/fncel.2018.00290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022] Open
Abstract
Post-translational modifications (PTMs), including phosphorylation, acetylation, ubiquitination, SUMOylation, etc., of proteins can modulate protein properties such as intracellular distribution, activity, stability, aggregation, and interactions. Therefore, PTMs are vital regulatory mechanisms for multiple cellular processes. Spinocerebellar ataxias (SCAs) are hereditary, heterogeneous, neurodegenerative diseases for which the primary manifestation involves ataxia. Because the pathogenesis of most SCAs is correlated with mutant proteins directly or indirectly, the PTMs of disease-related proteins might functionally affect SCA development and represent potential therapeutic interventions. Here, we review multiple PTMs related to disease-causing proteins in SCAs pathogenesis and their effects. Furthermore, we discuss these PTMs as potential targets for treating SCAs and describe translational therapies targeting PTMs that have been published.
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Affiliation(s)
- Linlin Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Keqin Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Parkinson’s Disease Center of Beijing Institute for Brain Disorders, Beijing, China
- Collaborative Innovation Center for Brain Science, Shanghai, China
- Collaborative Innovation Center for Genetics and Development, Shanghai, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Department of Neurology, Xinjiang Medical University, Ürümqi, China
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14
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Morona R, López JM, Northcutt RG, González A. Regional chemoarchitecture of the brain of lungfishes based on calbindin D-28K and calretinin immunohistochemistry. J Comp Neurol 2018. [PMID: 29520817 DOI: 10.1002/cne.24422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lungfishes are the closest living relatives of land vertebrates, and their neuroanatomical organization is particularly relevant for deducing the neural traits that have been conserved, modified, or lost with the transition from fishes to land vertebrates. The immunohistochemical localization of calbindin (CB) and calretinin (CR) provides a powerful method for discerning segregated neuronal populations, fiber tracts, and neuropils and is here applied to the brains of Neoceratodus and Protopterus, representing the two extant orders of lungfishes. The results showed abundant cells containing these proteins in pallial and subpallial telencephalic regions, with particular distinct distribution in the basal ganglia, amygdaloid complex, and septum. Similarly, the distribution of CB and CR containing cells supports the division of the hypothalamus of lungfishes into neuromeric regions, as in tetrapods. The dense concentrations of CB and CR positive cells and fibers highlight the extent of the thalamus. As in other vertebrates, the optic tectum is characterized by numerous CB positive cells and fibers and smaller numbers of CR cells. The so-called cerebellar nucleus contains abundant CB and CR cells with long ascending axons, which raises the possibility that it could be homologized to the secondary gustatory nucleus of other vertebrates. The corpus of the cerebellum is devoid of CB and CR and cells positive for both proteins are found in the cerebellar auricles and the octavolateralis nuclei. Comparison with other vertebrates reveals that lungfishes share most of their features of calcium binding protein distribution with amphibians, particularly with salamanders.
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Affiliation(s)
- Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Spain
| | - Jesús M López
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Spain
| | - R Glenn Northcutt
- Laboratory of Comparative Neurobiology, Scripps Institution of Oceanography and Department of Neurosciences, School of Medicine, , University of California, San Diego, California, USA
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Spain
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15
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Expression of Calcium-Binding Proteins, Calbindin D28k and Calretinin, in the Frog Taste Receptor Structures. NEUROPHYSIOLOGY+ 2017. [DOI: 10.1007/s11062-017-9679-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Calbindin-D-28K like immunoreactivity in superficial dorsal horn neurons and effects of sciatic chronic constriction injury. Neuroscience 2016; 324:330-43. [DOI: 10.1016/j.neuroscience.2016.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/18/2016] [Accepted: 03/05/2016] [Indexed: 11/23/2022]
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17
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McMahon SM, Chang CW, Jackson MB. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals. ACTA ACUST UNITED AC 2016; 147:243-54. [PMID: 26880753 PMCID: PMC4772375 DOI: 10.1085/jgp.201511525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/06/2016] [Indexed: 01/03/2023]
Abstract
Researchers have measured the ability of nerve terminals to buffer Ca2+ entering in response to electrical activity to better understand plasticity of hormone release. Cytosolic Ca2+ buffers bind to a large fraction of Ca2+ as it enters a cell, shaping Ca2+ signals both spatially and temporally. In this way, cytosolic Ca2+ buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca2+ entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca2+ buffers in controlling pituitary Ca2+ signaling is poorly understood. Here, cytosolic Ca2+ buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca2+ indicator fluo-8 revealed stepwise increases in free Ca2+ after a series of brief depolarizing pulses in rapid succession. These Ca2+ increments grew larger as free Ca2+ rose to saturate the cytosolic buffers and reduce the availability of Ca2+ binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5–4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca2+ buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca2+ signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones.
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Affiliation(s)
- Shane M McMahon
- Biophysics PhD Program, Department of Neuroscience, and Physiology PhD Program, University of Wisconsin, Madison, WI 53705
| | - Che-Wei Chang
- Biophysics PhD Program, Department of Neuroscience, and Physiology PhD Program, University of Wisconsin, Madison, WI 53705 Biophysics PhD Program, Department of Neuroscience, and Physiology PhD Program, University of Wisconsin, Madison, WI 53705
| | - Meyer B Jackson
- Biophysics PhD Program, Department of Neuroscience, and Physiology PhD Program, University of Wisconsin, Madison, WI 53705
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18
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Matthews EA, Dietrich D. Buffer mobility and the regulation of neuronal calcium domains. Front Cell Neurosci 2015; 9:48. [PMID: 25750615 PMCID: PMC4335178 DOI: 10.3389/fncel.2015.00048] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/31/2015] [Indexed: 11/13/2022] Open
Abstract
The diffusion of calcium inside neurons is determined in part by the intracellular calcium binding species that rapidly bind to free calcium ions upon entry. It has long been known that some portion of a neuron's intracellular calcium binding capacity must be fixed or poorly mobile, as calcium diffusion is strongly slowed in the intracellular environment relative to diffusion in cytosolic extract. The working assumption was that these immobile calcium binding sites are provided by structural proteins bound to the cytoskeleton or intracellular membranes and may thereby be relatively similar in composition and capacity across different cell types. However, recent evidence suggests that the immobile buffering capacity can vary greatly between cell types and that some mobile calcium binding proteins may alter their mobility upon binding calcium, thus blurring the line between mobile and immobile. The ways in which immobile buffering capacity might be relevant to different calcium domains within neurons has been explored primarily through modeling. In certain regimes, the presence of immobile buffers and the interaction between mobile and immobile buffers have been shown to result in complex spatiotemporal patterns of free calcium. In total, these experimental and modeling findings call for a more nuanced consideration of the local intracellular calcium microenvironment. In this review we focus on the different amounts, affinities, and mobilities of immobile calcium binding species; propose a new conceptual category of physically diffusible but functionally immobile buffers; and discuss how these buffers might interact with mobile calcium binding partners to generate characteristic calcium domains.
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Affiliation(s)
- Elizabeth A. Matthews
- Experimental Neurophysiology, Department of Neurosurgery, University Clinic BonnBonn, Germany
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19
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Brachtendorf S, Eilers J, Schmidt H. A use-dependent increase in release sites drives facilitation at calretinin-deficient cerebellar parallel-fiber synapses. Front Cell Neurosci 2015; 9:27. [PMID: 25691858 PMCID: PMC4315043 DOI: 10.3389/fncel.2015.00027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/15/2015] [Indexed: 12/13/2022] Open
Abstract
Endogenous Ca(2+)-binding proteins affect synaptic transmitter release and short-term plasticity (STP) by buffering presynaptic Ca(2+) signals. At parallel-fiber (PF)-to-Purkinje neuron (PN) synapses in the cerebellar cortex loss of calretinin (CR), the major buffer at PF terminals, results in increased presynaptic Ca(2+) transients and an almost doubling of the initial vesicular releases probability (p r). Surprisingly, however, it has been reported that loss of CR from PF synapses does not alter paired-pulse facilitation (PPF), while it affects presynaptic Ca(2+) signals as well as p r. Here, we addressed this puzzling observation by analyzing the frequency- and Ca(2+)-dependence of PPF at unitary PF-to-PN synapses of wild-type (WT) and CR-deficient (CR(-/-)) mice using paired recordings and computer simulations. Our analysis revealed that PPF in CR(-/-) is indeed smaller than in the WT, to a degree, however, that indicates that rapid vesicle replenishment and recruitment of additional release sites dominate the synaptic efficacy of the second response. These Ca(2+)-driven processes operate more effectively in the absence of CR, thereby, explaining the preservation of robust PPF in the mutants.
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Affiliation(s)
- Simone Brachtendorf
- Medical Faculty, Carl-Ludwig-Institute for Physiology, University of Leipzig Leipzig, Germany
| | - Jens Eilers
- Medical Faculty, Carl-Ludwig-Institute for Physiology, University of Leipzig Leipzig, Germany
| | - Hartmut Schmidt
- Medical Faculty, Carl-Ludwig-Institute for Physiology, University of Leipzig Leipzig, Germany
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20
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GENG YU, LIN HAOTIAN, CHEN WAN, LIU ZHAOCHUAN, XIANG WU, CHEN WEIRONG. Age-related reduction in calbindin-D28K expression in the Sprague-Dawley rat lens. Mol Med Rep 2014; 11:422-6. [DOI: 10.3892/mmr.2014.2672] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 08/05/2014] [Indexed: 11/06/2022] Open
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21
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Anwar H, Roome CJ, Nedelescu H, Chen W, Kuhn B, De Schutter E. Dendritic diameters affect the spatial variability of intracellular calcium dynamics in computer models. Front Cell Neurosci 2014; 8:168. [PMID: 25100945 PMCID: PMC4107854 DOI: 10.3389/fncel.2014.00168] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/02/2014] [Indexed: 11/13/2022] Open
Abstract
There is growing interest in understanding calcium dynamics in dendrites, both experimentally and computationally. Many processes influence these dynamics, but in dendrites there is a strong contribution of morphology because the peak calcium levels are strongly determined by the surface to volume ratio (SVR) of each branch, which is inversely related to branch diameter. In this study we explore the predicted variance of dendritic calcium concentrations due to local changes in dendrite diameter and how this is affected by the modeling approach used. We investigate this in a model of dendritic calcium spiking in different reconstructions of cerebellar Purkinje cells and in morphological analysis of neocortical and hippocampal pyramidal neurons. We report that many published models neglect diameter-dependent effects on calcium concentration and show how to implement this correctly in the NEURON simulator, both for phenomenological pool based models and for implementations using radial 1D diffusion. More detailed modeling requires simulation of 3D diffusion and we demonstrate that this does not dissipate the local concentration variance due to changes of dendritic diameter. In many cases 1D diffusion of models of calcium buffering give a good approximation provided an increased morphological resolution is implemented.
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Affiliation(s)
- Haroon Anwar
- Theoretical Neurobiology and Neuroengineering, University of Antwerp Wilrijk, Belgium ; Computational Neuroscience Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
| | - Christopher J Roome
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
| | - Hermina Nedelescu
- Theoretical Neurobiology and Neuroengineering, University of Antwerp Wilrijk, Belgium ; Computational Neuroscience Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
| | - Weiliang Chen
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
| | - Bernd Kuhn
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
| | - Erik De Schutter
- Theoretical Neurobiology and Neuroengineering, University of Antwerp Wilrijk, Belgium ; Computational Neuroscience Unit, Okinawa Institute of Science and Technology Onna-Son, Okinawa, Japan
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22
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Flace P, Lorusso L, Laiso G, Rizzi A, Cagiano R, Nico B, Ribatti D, Ambrosi G, Benagiano V. Calbindin-D28K immunoreactivity in the human cerebellar cortex. Anat Rec (Hoboken) 2014; 297:1306-15. [PMID: 24719368 DOI: 10.1002/ar.22921] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/21/2014] [Accepted: 02/22/2014] [Indexed: 01/16/2023]
Abstract
Calbindin-D28k (CB) is a calcium-binding protein largely distributed in the cerebellum of various species of vertebrates. As regards the human cerebellar cortex, precise data on the distribution of CB have not yet been reported. Aim of the present work was to analyze the distribution of CB in postmortem samples of human cerebellar cortex using light microscopy immunohistochemical techniques. Immunoreactivity to CB was detected within neuronal bodies and processes distributed in all cortex layers. In the molecular layer, the immunoreactivity was observed in subpopulations of stellate and basket neurons. In the Purkinje neuron layer, the immunoreactivity was observed in practically all the Purkinje neurons. In the granular layer, the immunoreactivity was observed in subpopulations of granules, of Golgi neurons, and also of other types of large neurons (candelabrum, Lugaro neurons, etc.). Immunoreactivity to CB was also observed in axon terminals distributed throughout the cortex according to layer-specific patterns of distribution. The qualitative and quantitative patterns of distribution of CB showed no difference among the different lobes of the cerebellar cortex. This study reports that CB is expressed by different neuron types, both inhibitory (GABAergic) and excitatory (glutamatergic), involved in both intrinsic and extrinsic circuits of the human cerebellar cortex. The study provides further insights on the functional role of CB and on the neuronal types of the cerebellar cortex in which it is expressed.
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Affiliation(s)
- Paolo Flace
- Dip. Scienze Mediche di Base, Neuroscienze e Organi di Senso, Policlinico, Piazza Giulio Cesare, Bari, Italy
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23
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Thangavel M, Seelan RS, Lakshmanan J, Vadnal RE, Stagner JI, Parthasarathy LK, Casanova MF, El-Mallakh RS, Parthasarathy RN. Proteomic analysis of rat prefrontal cortex after chronic valproate treatment. J Neurosci Res 2014; 92:927-36. [DOI: 10.1002/jnr.23373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/28/2014] [Accepted: 01/28/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Muthusamy Thangavel
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
| | - Ratnam S. Seelan
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
- Department of Molecular; Cellular; and Craniofacial Biology; School of Dentistry, University of Louisville; Louisville Kentucky
| | - Jaganathan Lakshmanan
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
- Price Institute of Surgical Research; Department of Surgery; School of Medicine, University of Louisville; Louisville Kentucky
| | - Robert E. Vadnal
- Eastern Colorado Health Care System; Department of Veterans Affairs; Pueblo Colorado
| | - John I. Stagner
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
| | - Latha K. Parthasarathy
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
| | - Manuel F. Casanova
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
| | - Rifaat Shody El-Mallakh
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
| | - Ranga N. Parthasarathy
- Molecular Neuroscience and Bioinformatics Laboratories; Mental Health; Behavioral Science; and Research Services; Robley Rex Veterans Affairs Medical Center; Louisville Kentucky
- Department of Psychiatry and Behavioral Sciences; University of Louisville; Louisville Kentucky
- Department of Biochemistry and Molecular Biology; University of Louisville; Louisville Kentucky
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24
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Levi I, Eskira Y, Eisenstein M, Gilon C, Hoffman A, Tal-Gan Y, Fanous J, Bersudsky Y, Belmaker RH, Agam G, Almog O, Almog O. Inhibition of inositol monophosphatase (IMPase) at the calbindin-D28k binding site: molecular and behavioral aspects. Eur Neuropsychopharmacol 2013; 23:1806-15. [PMID: 23619164 DOI: 10.1016/j.euroneuro.2013.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 01/01/2013] [Accepted: 02/08/2013] [Indexed: 01/13/2023]
Abstract
Bipolar-disorder (manic-depressive illness) is a severe chronic illness affecting ∼1% of the adult population. It is treated with mood-stabilizers, the prototypic one being lithium-salts (lithium), but it has life threatening side-effects and a significant number of patients fail to respond. The lithium-inhibitable enzyme inositol-monophosphatase (IMPase) is one of the viable targets for lithium's mechanism of action. Calbindin-D28k (calbindin) up-regulates IMPase activity. The IMPase-calbindincomplex was modeled using the program MolFit. The in-silico model indicated that the 55-66 amino-acid segment of IMPase anchors calbindin via Lys59 and Lys61 with a glutamate in between (Lys-Glu-Lys motif) and that the motif interacts with residues Asp24 and Asp26 of calbindin. We found that differently from wildtype calbindin, IMPase was not activated by mutated calbindin in which Asp24 and Asp26 were replaced by alanine. Calbindin's effect was significantly reduced by a linear peptide with the sequence of amino acids 58-63 of IMPase (peptide 1) and by six amino-acid linear peptides including at least part of the Lys-Glu-Lys motif. The three amino-acid peptide Lys-Glu-Lys or five amino-acid linear peptides containing this motif were ineffective. Mice administered peptide 1 intracerebroventricularly exhibited a significant anti-depressant-like reduced immobility in the forced-swim test. Based on the sequence of peptide 1, and to potentially increase the peptide's stability, cyclic and linear pre-cyclic analog peptides were synthesized. One cyclic peptide and one linear pre-cyclic analog peptide inhibited calbindin-activated brain IMPase activity in-vitro. Our findings may lead to the development of molecules capable of inhibiting IMPase activity at an alternative site than that of lithium.
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Affiliation(s)
- Itzhak Levi
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Psychiatry Research Unit, Mental Health Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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25
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Tuning local calcium availability: cell-type-specific immobile calcium buffer capacity in hippocampal neurons. J Neurosci 2013; 33:14431-45. [PMID: 24005295 DOI: 10.1523/jneurosci.4118-12.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
It has remained difficult to ascribe a specific functional role to immobile or fixed intracellular calcium buffers in central neurons because the amount of these buffers is unknown. Here, we explicitly isolated the fixed buffer fraction by prolonged whole-cell patch-clamp dialysis and quantified its buffering capacity in murine hippocampal slices using confocal calcium imaging and the "added-buffer" approach. In dentate granule cells, the calcium binding ratio (κ) after complete washout of calbindin D28k (Cb), κfixed, displayed a substantial value of ∼100. In contrast, in CA1 oriens lacunosum moleculare (OLM) interneurons, which do not contain any known calcium-binding protein(s), κfixed amounted to only ∼30. Based on these values, a theoretical analysis of dendritic spread of calcium after local entry showed that fixed buffers, in the absence of mobile species, decrease intracellular calcium mobility 100- and 30-fold in granule cells and OLM cells, respectively, and thereby strongly slow calcium signals. Although the large κfixed alone strongly delays the spread of calcium in granule cells, this value optimizes the benefits of additionally expressing the mobile calcium binding protein Cb. With such high κfixed, Cb effectively increases the propagation velocity to levels seen in OLM cells and, contrary to expectation, does not affect the peak calcium concentration close to the source but sharpens the spatial and temporal calcium gradients. The data suggest that the amount of fixed buffers determines the temporal availability of calcium for calcium-binding partners and plays a pivotal role in setting the repertoire of cellular calcium signaling regimens.
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26
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Giráldez-Pérez RM, Avila MN, Feijóo-Cuaresma M, Heredia R, De Diego-Otero Y, Real MÁ, Guirado S. Males but not females show differences in calbindin immunoreactivity in the dorsal thalamus of the mouse model of fragile X syndrome. J Comp Neurol 2013; 521:894-911. [PMID: 22886886 DOI: 10.1002/cne.23209] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 06/04/2012] [Accepted: 08/03/2012] [Indexed: 12/18/2022]
Abstract
Fragile X syndrome (FXS), the most common form of inherited mental retardation, is caused by the loss of the Fmr1 gene product, fragile X mental retardation protein. Here we analyze the immunohistochemical expression of calcium-binding proteins in the dorsal thalamus of Fmr1 knockout mice of both sexes and compare it with that of wildtype littermates. The spatial distribution pattern of calbindin-immunoreactive cells in the dorsal thalamus was similar in wildtype and knockout mice but there was a notable reduction in calbindin-immunoreactive cells in midline/intralaminar/posterior dorsal thalamic nuclei of male Fmr1 knockout mice. We counted the number of calbindin-immunoreactive cells in 18 distinct nuclei of the dorsal thalamus. Knockout male mice showed a significant reduction in calbindin-immunoreactive cells (range: 36-67% lower), whereas female knockout mice did not show significant differences (in any dorsal thalamic nucleus) when compared with their wildtype littermates. No variation in the calretinin expression pattern was observed throughout the dorsal thalamus. The number of calretinin-immunoreactive cells was similar for all experimental groups as well. Parvalbumin immunoreactivity was restricted to fibers and neuropil in the analyzed dorsal thalamic nuclei, and presented no differences between genotypes. Midline/intralaminar/posterior dorsal thalamic nuclei are involved in forebrain circuits related to memory, nociception, social fear, and auditory sensory integration; therefore, we suggest that downregulation of calbindin protein expression in the dorsal thalamus of male knockout mice should be taken into account when analyzing behavioral studies in the mouse model of FXS.
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Affiliation(s)
- Rosa M Giráldez-Pérez
- University of Málaga, Department of Cell Biology, Genetics, and Physiology, Málaga, Spain
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27
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Arendt O, Schwaller B, Brown EB, Eilers J, Schmidt H. Restricted diffusion of calretinin in cerebellar granule cell dendrites implies Ca²⁺-dependent interactions via its EF-hand 5 domain. J Physiol 2013; 591:3887-99. [PMID: 23732647 DOI: 10.1113/jphysiol.2013.256628] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Ca²⁺-binding proteins (CaBPs) are important regulators of neuronal Ca²⁺ signalling, acting either as buffers that shape Ca²⁺ transients and Ca²⁺ diffusion and/or as Ca²⁺ sensors. The diffusional mobility represents a crucial functional parameter of CaBPs, describing their range-of-action and possible interactions with binding partners. Calretinin (CR) is a CaBP widely expressed in the nervous system with strong expression in cerebellar granule cells. It is involved in regulating excitability and synaptic transmission of granule cells, and its absence leads to impaired motor control. We quantified the diffusional mobility of dye-labelled CR in mouse granule cells using two-photon fluorescence recovery after photobleaching. We found that movement of macromolecules in granule cell dendrites was not well described by free Brownian diffusion and that CR diffused unexpectedly slow compared to fluorescein dextrans of comparable size. During bursts of action potentials, which were associated with dendritic Ca²⁺ transients, the mobility of CR was further reduced. Diffusion was significantly accelerated by a peptide embracing EF-hand 5 of CR. Our results suggest long-lasting, Ca²⁺-dependent interactions of CR with large and/or immobile binding partners. These interactions render CR a poorly mobile Ca²⁺ buffer and point towards a Ca²⁺ sensor function of CR.
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Affiliation(s)
- Oliver Arendt
- Carl-Ludwig-Institute for Physiology, Medical Faculty, University Leipzig, Germany
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Bornschein G, Arendt O, Hallermann S, Brachtendorf S, Eilers J, Schmidt H. Paired-pulse facilitation at recurrent Purkinje neuron synapses is independent of calbindin and parvalbumin during high-frequency activation. J Physiol 2013; 591:3355-70. [PMID: 23671160 DOI: 10.1113/jphysiol.2013.254128] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Paired-pulse facilitation (PPF) is a dynamic enhancement of transmitter release considered crucial in CNS information processing. The mechanisms of PPF remain controversial and may differ between synapses. Endogenous Ca(2+) buffers such as parvalbumin (PV) and calbindin-D28k (CB) are regarded as important modulators of PPF, with PV acting as an anti-facilitating buffer while saturation of CB can promote PPF. We analysed transmitter release and PPF at intracortical, recurrent Purkinje neuron (PN) to PN synapses, which show PPF during high-frequency activation (200 Hz) and strongly express both PV and CB. We quantified presynaptic Ca(2+) dynamics and quantal release parameters in wild-type (WT), and CB and PV deficient mice. Lack of CB resulted in increased volume averaged presynaptic Ca(2+) amplitudes and in increased release probability, while loss of PV had no significant effect on these parameters. Unexpectedly, none of the buffers significantly influenced PPF, indicating that neither CB saturation nor residual free Ca(2+) ([Ca(2+)]res) was the main determinant of PPF. Experimentally constrained, numerical simulations of Ca(2+)-dependent release were used to estimate the contributions of [Ca(2+)]res, CB, PV, calmodulin (CaM), immobile buffer fractions and Ca(2+) remaining bound to the release sensor after the first of two action potentials ('active Ca(2+)') to PPF. This analysis indicates that PPF at PN-PN synapses does not result from either buffer saturation or [Ca(2+)]res but rather from slow Ca(2+) unbinding from the release sensor.
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Affiliation(s)
- Grit Bornschein
- Carl-Ludwig Institute for Physiology, University of Leipzig, Liebigstr. 27, 04103 Leipzig, Germany
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Staras K, Mikulincer D, Gitler D. Monitoring and quantifying dynamic physiological processes in live neurons using fluorescence recovery after photobleaching. J Neurochem 2013; 126:213-22. [PMID: 23496032 DOI: 10.1111/jnc.12240] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 12/27/2022]
Abstract
The direct visualization of subcellular dynamic processes is often hampered by limitations in the resolving power achievable with conventional microscopy techniques. Fluorescence recovery after photobleaching has emerged as a highly informative approach to address this challenge, permitting the quantitative measurement of the movement of small organelles and proteins in living functioning cells, and offering detailed insights into fundamental cellular phenomena of physiological importance. In recent years, its implementation has benefited from the increasing availability of confocal microscopy systems and of powerful labeling techniques based on genetically encoded fluorescent proteins or other chemical markers. In this review, we present fluorescence recovery after photobleaching and related techniques in the context of contemporary neurobiological research and discuss quantitative and semi-quantitative approaches to their interpretation.
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Affiliation(s)
- Kevin Staras
- School of Life Sciences, University of Sussex, Brighton, UK
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Fosser NS, Ronco L, Bejarano A, Paganelli AR, Ríos H. Calbindin-D28k and calretinin in chicken inner retina during postnatal development and neuroplasticity by dim red light. Dev Neurobiol 2013; 73:530-42. [PMID: 23447106 DOI: 10.1002/dneu.22081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 01/01/2023]
Abstract
Members of the family of calcium binding proteins (CBPs) are involved in the buffering of calcium (Ca2+) by regulating how Ca2+ can operate within synapses or more globally in the entire cytoplasm and they are present in a particular arrangement in all types of retinal neurons. Calbindin D28k and calretinin belong to the family of CBPs and they are mainly co-expressed with other CBPs. Calbindin D28k is expressed in doubles cones, bipolar cells and in a subpopulation of amacrine and ganglion neurons. Calretinin is present in horizontal cells as well as in a subpopulation of amacrine and ganglion neurons. Both proteins fill the soma at the inner nuclear layer and the neuronal projections at the inner plexiform layer. Moreover, calbindin D28k and calretinin have been associated with neuronal plasticity in the central nervous system. During pre and early postnatal visual development, the visual system shows high responsiveness to environmental influences. In this work we observed modifications in the pattern of stratification of calbindin immunoreactive neurons, as well as in the total amount of calbindin through the early postnatal development. In order to test whether or not calbindin is involved in retinal plasticity we analyzed phosphorylated p38 MAPK expression, which showed a decrease in p-p38 MAPK, concomitant to the observed decrease of calbindin D28k. Results showed in this study suggest that calbindin is a molecule related with neuroplasticity, and we suggest that calbindin D28k has significant roles in neuroplastic changes in the retina, when retinas are stimulated with different light conditions.
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Affiliation(s)
- Nicolás Sebastián Fosser
- Instituto de Biología Celular y Neurociencias Prof. E. De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 2do. piso, Ciudad Autónoma de Buenos Aires, C1121ABG, Argentina
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Diffusion and extrusion shape standing calcium gradients during ongoing parallel fiber activity in dendrites of Purkinje neurons. THE CEREBELLUM 2012; 11:694-705. [PMID: 21298581 DOI: 10.1007/s12311-010-0246-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Synaptically induced calcium transients in dendrites of Purkinje neurons (PNs) play a key role in the induction of plasticity in the cerebellar cortex (Ito, Physiol Rev 81:1143-1195, 2001). Long-term depression at parallel fiber-PN synapses can be induced by stimulation paradigms that are associated with long-lasting (>1 min) calcium signals. These signals remain strictly localized (Eilers et al., Learn Mem 3:159-168, 1997), an observation that was rather unexpected, given the high concentration of the mobile endogenous calcium-binding proteins parvalbumin and calbindin in PNs (Fierro and Llano, J Physiol (Lond) 496:617-625, 1996; Kosaka et al., Exp Brain Res 93:483-491, 1993). By combining two-photon calcium imaging experiments in acute slices with numerical computer simulations, we found that significant calcium diffusion out of active branches indeed takes places. It is outweighed, however, by rapid and powerful calcium extrusion along the dendritic shaft. The close interplay of diffusion and extrusion defines the spread of calcium between active and inactive dendritic branches, forming a steep gradient in calcium with drop ranges of ~13 μm (interquartile range, 10-18 μm).
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Abstract
Intracellular calcium dynamics is critical for many functions of cerebellar granule cells (GrCs) including membrane excitability, synaptic plasticity, apoptosis, and regulation of gene transcription. Recent measurements of calcium responses in GrCs to depolarization and synaptic stimulation reveal spatial compartmentalization and heterogeneity within dendrites of these cells. However, the main determinants of local calcium dynamics in GrCs are still poorly understood. One reason is that there have been few published studies of calcium dynamics in intact GrCs in their native environment. In the absence of complete information, biophysically realistic models are useful for testing whether specific Ca(2+) handling mechanisms may account for existing experimental observations. Simulation results can be used to identify critical measurements that would discriminate between different models. In this review, we briefly describe experimental studies and phenomenological models of Ca(2+) signaling in GrC, and then discuss a particular biophysical model, with a special emphasis on an approach for obtaining information regarding the distribution of Ca(2+) handling systems under conditions of incomplete experimental data. Use of this approach suggests that Ca(2+) channels and fixed endogenous Ca(2+) buffers are highly heterogeneously distributed in GrCs. Research avenues for investigating calcium dynamics in GrCs by a combination of experimental and modeling studies are proposed.
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Affiliation(s)
- Elena È Saftenku
- Department of General Physiology of Nervous System, A. A. Bogomoletz Institute of Physiology, 4 Bogomoletz St., Kyiv 01024, Ukraine.
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Saftenku EÈ. Effects of calretinin on Ca2+ signals in cerebellar granule cells: implications of cooperative Ca2+ binding. THE CEREBELLUM 2012; 11:102-20. [PMID: 21394464 DOI: 10.1007/s12311-011-0263-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Calretinin is thought to be the main endogenous calcium buffer in cerebellar granule cells (GrCs). However, little is known about the impact of cooperative Ca(2+) binding to calretinin on highly localized and more global (regional) Ca(2+) signals in these cells. Using numerical simulations, we show that an essential property of calretinin is a delayed equilibration with Ca(2+). Therefore, the amount of Ca(2+), which calretinin can accumulate with respect to equilibrium levels, depends on stimulus conditions. Based on our simulations of buffered Ca(2+) diffusion near a single Ca(2+) channel or a large cluster of Ca(2+) channels and previous experimental findings that 150 μM 1,2-bis(o-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid (BAPTA) and endogenous calretinin have similar effects on GrC excitability, we estimated the concentration of mobile calretinin in GrCs in the range of 0.7-1.2 mM. Our results suggest that this estimate can provide a starting point for further analysis. We find that calretinin prominently reduces the action potential associated increase in cytosolic free Ca(2+) concentration ([Ca(2+)]( i )) even at a distance of 30 nm from a single Ca(2+) channel. In spite of a buildup of residual Ca(2+), it maintains almost constant maximal [Ca(2+)]( i ) levels during repetitive channel openings with a frequency less than 80 Hz. This occurs because of accelerated Ca(2+) binding as calretinin binds more Ca(2+). Unlike the buffering of high Ca(2+) levels within Ca(2+) nano/microdomains sensed by large conductance Ca(2+)-activated K(+) channels, the buffering of regional Ca(2+) signals by calretinin can never be mimicked by certain concentration of BAPTA under all different experimental conditions.
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Affiliation(s)
- Elena È Saftenku
- Department of General Physiology of Nervous System, A. A. Bogomoletz Institute of Physiology, Bogomoletz St., 4, Kyiv 01024, Ukraine.
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Chudinova TV, Belekhova MG, Tostivint H, Ward R, Rio JP, Kenigfest NB. Differences in parvalbumin and calbindin chemospecificity in the centers of the turtle ascending auditory pathway revealed by double immunofluorescence labeling. Brain Res 2012; 1473:87-103. [DOI: 10.1016/j.brainres.2012.07.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 06/06/2012] [Accepted: 07/12/2012] [Indexed: 10/28/2022]
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The use of transgenic mouse models to reveal the functions of Ca2+ buffer proteins in excitable cells. Biochim Biophys Acta Gen Subj 2012; 1820:1294-303. [DOI: 10.1016/j.bbagen.2011.11.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 11/14/2011] [Accepted: 11/15/2011] [Indexed: 12/19/2022]
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Joven A, Morona R, Moreno N, González A. Regional distribution of calretinin and calbindin-D28k expression in the brain of the urodele amphibian Pleurodeles waltl during embryonic and larval development. Brain Struct Funct 2012; 218:969-1003. [PMID: 22843286 DOI: 10.1007/s00429-012-0442-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/07/2012] [Indexed: 11/28/2022]
Abstract
The sequence of appearance of calretinin and calbindin-D28k immunoreactive (CRir and CBir, respectively) cells and fibers has been studied in the brain of the urodele amphibian Pleurodeles waltl. Embryonic, larval and juvenile stages were studied. The early expression and the dynamics of the distribution of CBir and CRir structures have been used as markers for developmental aspects of distinct neuronal populations, highlighting the accurate extent of many regions in the developing brain, not observed on the basis of cytoarchitecture alone. CR and, to a lesser extent, CB are expressed early in the central nervous system and show a progressively increasing expression from the embryonic stages throughout the larval life and, in general, the labeled structures in the developing brain retain their ability to express these proteins in the adult brain. The onset of CRir cells primarily served to follow the development of the olfactory bulbs, subpallium, thalamus, alar hypothalamus, mesencephalic tegmentum, and distinct cell populations in the rhombencephalic reticular formation. CBir cells highlighted the development of, among others, the pallidum, hypothalamus, dorsal habenula, midbrain tegmentum, cerebellum, and central gray of the rostral rhombencephalon. However, it was the relative and mostly segregated distribution of both proteins in distinct cell populations which evidenced the developing regionalization of the brain. The results have shown the usefulness in neuroanatomy of the analysis during development of the onset of CBir and CRir structures, but the comparison with previous data has shown extensive variability across vertebrate classes. Therefore, one should be cautious when comparing possible homologue structures across species only on the basis of the expression of these proteins, due to the variation of the content of calcium-binding proteins observed in well-established homologous regions in the brain of different vertebrates.
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Affiliation(s)
- Alberto Joven
- Departamento de Biología Celular, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain
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Bischop DP, Orduz D, Lambot L, Schiffmann SN, Gall D. Control of neuronal excitability by calcium binding proteins: a new mathematical model for striatal fast-spiking interneurons. Front Mol Neurosci 2012; 5:78. [PMID: 22787441 PMCID: PMC3392946 DOI: 10.3389/fnmol.2012.00078] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/18/2012] [Indexed: 11/18/2022] Open
Abstract
Calcium binding proteins, such as parvalbumin (PV), are abundantly expressed in distinctive patterns in the central nervous system but their physiological function remains poorly understood. Notably, at the level of the striatum, where PV is only expressed in the fast-spiking (FS) interneurons. FS interneurons form an inhibitory network modulating the output of the striatum by synchronizing medium-sized spiny neurons (MSN). So far the existing conductance-based computational models for FS neurons did not allow the study of the coupling between PV concentration and electrical activity. In the present paper, we propose a new mathematical model for the striatal FS interneurons that includes apamin-sensitive small conductance Ca2+-dependent K+ channels (SK) and the presence of a calcium buffer. Our results show that a variation in the concentration of PV can modulate substantially the intrinsic excitability of the FS interneurons and therefore may be involved in the information processing at the striatal level.
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Affiliation(s)
- D P Bischop
- Laboratoire de Neurophysiologie, Faculté de Médecine, Université Libre de Bruxelles Bruxelles, Belgium
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38
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Raghuram V, Sharma Y, Kreutz MR. Ca(2+) sensor proteins in dendritic spines: a race for Ca(2+). Front Mol Neurosci 2012; 5:61. [PMID: 22586368 PMCID: PMC3347464 DOI: 10.3389/fnmol.2012.00061] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 04/18/2012] [Indexed: 12/21/2022] Open
Abstract
Dendritic spines are believed to be micro-compartments of Ca2+ regulation. In a recent study, it was suggested that the ubiquitous and evolutionarily conserved Ca2+ sensor, calmodulin (CaM), is the first to intercept Ca2+ entering the spine and might be responsible for the fast decay of Ca2+ transients in spines. Neuronal calcium sensor (NCS) and neuronal calcium-binding protein (nCaBP) families consist of Ca2+ sensors with largely unknown synaptic functions despite an increasing number of interaction partners. Particularly how these sensors operate in spines in the presence of CaM has not been discussed in detail before. The limited Ca2+ resources and the existence of common targets create a highly competitive environment where Ca2+ sensors compete with each other for Ca2+ and target binding. In this review, we take a simple numerical approach to put forth possible scenarios and their impact on signaling via Ca2+ sensors of the NCS and nCaBP families. We also discuss the ways in which spine geometry and properties of ion channels, their kinetics and distribution, alter the spatio-temporal aspects of Ca2+ transients in dendritic spines, whose interplay with Ca2+ sensors in turn influences the race for Ca2+.
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Affiliation(s)
- Vijeta Raghuram
- Centre for Cellular and Molecular Biology, CSIR Hyderabad, India
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Schmidt H. Three functional facets of calbindin D-28k. Front Mol Neurosci 2012; 5:25. [PMID: 22435048 PMCID: PMC3304297 DOI: 10.3389/fnmol.2012.00025] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 02/14/2012] [Indexed: 11/13/2022] Open
Abstract
Many neurons of the vertebrate central nervous system (CNS) express the Ca2+ binding protein calbindin D-28k (CB), including important projection neurons like cerebellar Purkinje cells but also neocortical interneurons. CB has moderate cytoplasmic mobility and comprises at least four EF-hands that function in Ca2+ binding with rapid to intermediate kinetics and affinity. Classically it was viewed as a pure Ca2+ buffer important for neuronal survival. This view was extended by showing that CB is a critical determinant in the control of synaptic Ca2+ dynamics, presumably with strong impact on plasticity and information processing. Already 30 years ago, in vitro studies suggested that CB could have an additional Ca2+ sensor function, like its prominent acquaintance calmodulin (CaM). More recent work substantiated this hypothesis, revealing direct CB interactions with several target proteins. Different from a classical sensor, however, CB appears to interact with its targets both, in its Ca2+-loaded and Ca2+-free forms. Finally, CB has been shown to be involved in buffered transport of Ca2+, in neurons but also in kidney. Thus, CB serves a threefold function as buffer, transporter and likely as a non-canonical sensor.
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Affiliation(s)
- Hartmut Schmidt
- Medical Faculty, Carl-Ludwig Institute for Physiology, University of Leipzig Leipzig, Germany.
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Westerink RHS, Beekwilder JP, Wadman WJ. Differential alterations of synaptic plasticity in dentate gyrus and CA1 hippocampal area of Calbindin-D28K knockout mice. Brain Res 2012; 1450:1-10. [PMID: 22405690 DOI: 10.1016/j.brainres.2012.02.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 02/14/2012] [Accepted: 02/14/2012] [Indexed: 12/15/2022]
Abstract
Regulation of the intracellular calcium concentration ([Ca(2+)](i)) is of critical importance for synaptic function. Therefore, neurons buffer [Ca(2+)](i) using intracellular Ca(2+)-binding proteins (CaBPs). Previous evidence suggests that Calbindin-D(28K) (CB), an abundantly expressed endogenous fast CaBP, plays an important role in neuronal survival, motor coordination, spatial learning paradigms and some forms of synaptic plasticity. In the present study, the role of CB in synaptic transmission and plasticity was further investigated using extracellular recordings of synaptic activity in cell- and dendritic layers of dentate gyrus (DG) and CA1 area in hippocampal slices from wild-type, heterozygous and homozygous CB knockout mice. The results demonstrate a consistent failure to maintain long-term potentiation (LTP) in hippocampal DG and CA1 area of knockout mice. Compared to wild-type mice, the paired-pulse ratio of EPSPs recorded in DG is significantly lower in slices from knockout mice, whereas it is significantly higher in CA1 area. The amplitude of the population spike recorded in CA1 area of wild-type mice steadily increases following tetanic stimulation, whereas it steadily decreases in knockout mice. The combined results demonstrate that the absence of CB results in an impairment of LTP maintenance in both hippocampal DG and CA1 area, whereas paired-pulse facilitation and cellular excitability in CA1 area are differentially affected. These results support the role of CB as a critical determinant for several forms of synaptic plasticity in hippocampal DG and CA1 area. It is hypothesized that CB functions as a postsynaptic Ca(2+) buffer as well as a presynaptic Ca(2+) sensor.
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Affiliation(s)
- R H S Westerink
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
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41
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Maddock RJ, Buonocore MH. MR spectroscopic studies of the brain in psychiatric disorders. Curr Top Behav Neurosci 2012; 11:199-251. [PMID: 22294088 DOI: 10.1007/7854_2011_197] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The measurement of brain metabolites with magnetic resonance spectroscopy (MRS) provides a unique perspective on the brain bases of neuropsychiatric disorders. As a context for interpreting MRS studies of neuropsychiatric disorders, we review the characteristic MRS signals, the metabolic dynamics,and the neurobiological significance of the major brain metabolites that can be measured using clinical MRS systems. These metabolites include N-acetylaspartate(NAA), creatine, choline-containing compounds, myo-inositol, glutamate and glutamine, lactate, and gamma-amino butyric acid (GABA). For the major adult neuropsychiatric disorders (schizophrenia, bipolar disorder, major depression, and the anxiety disorders), we highlight the most consistent MRS findings, with an emphasis on those with potential clinical or translational significance. Reduced NAA in specific brain regions in schizophrenia, bipolar disorder, post-traumatic stress disorder, and obsessive–compulsive disorder corroborate findings of reduced brain volumes in the same regions. Future MRS studies may help determine the extent to which the neuronal dysfunction suggested by these findings is reversible in these disorders. Elevated glutamate and glutamine (Glx) in patients with bipolar disorder and reduced Glx in patients with unipolar major depression support models of increased and decreased glutamatergic function, respectively, in those conditions. Reduced phosphomonoesters and intracellular pH in bipolar disorder and elevated dynamic lactate responses in panic disorder are consistent with metabolic models of pathogenesis in those disorders. Preliminary findings of an increased glutamine/glutamate ratio and decreased GABA in patients with schizophrenia are consistent with a model of NMDA hypofunction in that disorder. As MRS methods continue to improve, future studies may further advance our understanding of the natural history of psychiatric illnesses, improve our ability to test translational models of pathogenesis, clarify therapeutic mechanisms of action,and allow clinical monitoring of the effects of interventions on brain metabolicmarkers
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The Regulation of a Cell’s Ca2+ Signaling Toolkit: The Ca2+ Homeostasome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1-25. [DOI: 10.1007/978-94-007-2888-2_1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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43
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Combined computational and experimental approaches to understanding the Ca(2+) regulatory network in neurons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:569-601. [PMID: 22453961 DOI: 10.1007/978-94-007-2888-2_26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Ca(2+) is a ubiquitous signaling ion that regulates a variety of neuronal functions by binding to and altering the state of effector proteins. Spatial relationships and temporal dynamics of Ca(2+) elevations determine many cellular responses of neurons to chemical and electrical stimulation. There is a wealth of information regarding the properties and distribution of Ca(2+) channels, pumps, exchangers, and buffers that participate in Ca(2+) regulation. At the same time, new imaging techniques permit characterization of evoked Ca(2+) signals with increasing spatial and temporal resolution. However, understanding the mechanistic link between functional properties of Ca(2+) handling proteins and the stimulus-evoked Ca(2+) signals they orchestrate requires consideration of the way Ca(2+) handling mechanisms operate together as a system in native cells. A wide array of biophysical modeling approaches is available for studying this problem and can be used in a variety of ways. Models can be useful to explain the behavior of complex systems, to evaluate the role of individual Ca(2+) handling mechanisms, to extract valuable parameters, and to generate predictions that can be validated experimentally. In this review, we discuss recent advances in understanding the underlying mechanisms of Ca(2+) signaling in neurons via mathematical modeling. We emphasize the value of developing realistic models based on experimentally validated descriptions of Ca(2+) transport and buffering that can be tested and refined through new experiments to develop increasingly accurate biophysical descriptions of Ca(2+) signaling in neurons.
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Eggermann E, Bucurenciu I, Goswami SP, Jonas P. Nanodomain coupling between Ca²⁺ channels and sensors of exocytosis at fast mammalian synapses. Nat Rev Neurosci 2011; 13:7-21. [PMID: 22183436 DOI: 10.1038/nrn3125] [Citation(s) in RCA: 352] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The physical distance between presynaptic Ca(2+) channels and the Ca(2+) sensors that trigger exocytosis of neurotransmitter-containing vesicles is a key determinant of the signalling properties of synapses in the nervous system. Recent functional analysis indicates that in some fast central synapses, transmitter release is triggered by a small number of Ca(2+) channels that are coupled to Ca(2+) sensors at the nanometre scale. Molecular analysis suggests that this tight coupling is generated by protein-protein interactions involving Ca(2+) channels, Ca(2+) sensors and various other synaptic proteins. Nanodomain coupling has several functional advantages, as it increases the efficacy, speed and energy efficiency of synaptic transmission.
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Affiliation(s)
- Emmanuel Eggermann
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria
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45
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Davidovic L, Navratil V, Bonaccorso CM, Catania MV, Bardoni B, Dumas ME. A metabolomic and systems biology perspective on the brain of the fragile X syndrome mouse model. Genome Res 2011; 21:2190-202. [PMID: 21900387 DOI: 10.1101/gr.116764.110] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fragile X syndrome (FXS) is the first cause of inherited intellectual disability, due to the silencing of the X-linked Fragile X Mental Retardation 1 gene encoding the RNA-binding protein FMRP. While extensive studies have focused on the cellular and molecular basis of FXS, neither human Fragile X patients nor the mouse model of FXS--the Fmr1-null mouse--have been profiled systematically at the metabolic and neurochemical level to provide a complementary perspective on the current, yet scattered, knowledge of FXS. Using proton high-resolution magic angle spinning nuclear magnetic resonance ((1)H HR-MAS NMR)-based metabolic profiling, we have identified a metabolic signature and biomarkers associated with FXS in various brain regions of Fmr1-deficient mice. Our study highlights for the first time that Fmr1 gene inactivation has profound, albeit coordinated consequences in brain metabolism leading to alterations in: (1) neurotransmitter levels, (2) osmoregulation, (3) energy metabolism, and (4) oxidative stress response. To functionally connect Fmr1-deficiency to its metabolic biomarkers, we derived a functional interaction network based on the existing knowledge (literature and databases) and show that the FXS metabolic response is initiated by distinct mRNA targets and proteins interacting with FMRP, and then relayed by numerous regulatory proteins. This novel "integrated metabolome and interactome mapping" (iMIM) approach advantageously unifies novel metabolic findings with previously unrelated knowledge and highlights the contribution of novel cellular pathways to the pathophysiology of FXS. These metabolomic and integrative systems biology strategies will contribute to the development of potential drug targets and novel therapeutic interventions, which will eventually benefit FXS patients.
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Affiliation(s)
- Laetitia Davidovic
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR 6097, 06560 Valbonne, France.
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Morona R, López JM, González A. Localization of Calbindin-D28k and Calretinin in the Brain of Dermophis Mexicanus (Amphibia: Gymnophiona) and Its Bearing on the Interpretation of Newly Recognized Neuroanatomical Regions. BRAIN, BEHAVIOR AND EVOLUTION 2011; 77:231-69. [DOI: 10.1159/000329521] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 05/12/2011] [Indexed: 12/13/2022]
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Abstract
"Ca(2+) buffers," a class of cytosolic Ca(2+)-binding proteins, act as modulators of short-lived intracellular Ca(2+) signals; they affect both the temporal and spatial aspects of these transient increases in [Ca(2+)](i). Examples of Ca(2+) buffers include parvalbumins (α and β isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Besides their proven Ca(2+) buffer function, some might additionally have Ca(2+) sensor functions. Ca(2+) buffers have to be viewed as one of the components implicated in the precise regulation of Ca(2+) signaling and Ca(2+) homeostasis. Each cell is equipped with proteins, including Ca(2+) channels, transporters, and pumps that, together with the Ca(2+) buffers, shape the intracellular Ca(2+) signals. All of these molecules are not only functionally coupled, but their expression is likely to be regulated in a Ca(2+)-dependent manner to maintain normal Ca(2+) signaling, even in the absence or malfunctioning of one of the components.
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Jinno S, Kosaka T. Stereological estimation of numerical densities of glutamatergic principal neurons in the mouse hippocampus. Hippocampus 2010; 20:829-40. [PMID: 19655319 DOI: 10.1002/hipo.20685] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent studies have emphasized functional dissociations between dorsal and ventral hippocampus in learning, emotion, and affect. A rigorous quantitative analysis concerning lamellar cytoarchitecture would be important for promoting further research on the regional differentiation of the hippocampus. Here, we stereologically estimated the numerical densities (NDs) of glutamatergic principal neurons in the mouse hippocampus and encountered the significant differences along the dorsoventral axis. In the CA1 region, the NDs of CA1 pyramidal neurons were almost three times higher at the dorsal level (447.5 x 10(3)/mm(3)) than at the ventral level (180.5 x 10(3)/mm(3)); meanwhile, along the transverse axis, the NDs were significantly higher in the proximal portion than in the distal portion both at the dorsal and ventral levels. An EF-hand calcium-binding protein, calbindin D28K, was expressed in approximately 45% of CA1 pyramidal neurons both at the dorsal and ventral level. In the CA3 region, there were no significant differences in the NDs along the dorsoventral and transverse axes (dorsal, 165.2 x 10(3)/mm(3); ventral, 172.4 x 10(3)/mm(3)). In the dentate gyrus (DG), the NDs of granule cells were significantly higher at the dorsal level (916.7 x 10(3)/mm(3)) than at the ventral level (788.9 x 10(3)/mm(3)). The significant differences were observed only in the suprapyramidal blade, but not in the infrapyramidal blade. Then, we calculated the total neuron numbers contained in a 300-microm-thick hypothetical transverse slice of the hippocampus and found that the ratios of GABAergic to glutamatergic neuron numbers were two to three times higher in the ventral slice than in the dorsal slice. The ratios of numbers of eight GABAergic neuron subtypes to principal cells indicate structural dissociations in the neural network between dorsal and ventral slices. These findings provide an essential quantitative basis for elucidating mechanisms of distinct neural circuits underlying various hippocampal functions.
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Affiliation(s)
- Shozo Jinno
- Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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Guzman SJ, Schmidt H, Franke H, Krügel U, Eilers J, Illes P, Gerevich Z. P2Y1 receptors inhibit long-term depression in the prefrontal cortex. Neuropharmacology 2010; 59:406-15. [PMID: 20570683 DOI: 10.1016/j.neuropharm.2010.05.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Revised: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 01/11/2023]
Abstract
Long-term depression (LTD) is a form of synaptic plasticity that may contribute to information storage in the central nervous system. Here we report that LTD can be elicited in layer 5 pyramidal neurons of the rat prefrontal cortex by pairing low frequency stimulation with a modest postsynaptic depolarization. The induction of LTD required the activation of both metabotropic glutamate receptors of the mGlu1 subtype and voltage-sensitive Ca(2+) channels (VSCCs) of the T/R, P/Q and N types, leading to the stimulation of intracellular inositol trisphosphate (IP3) receptors by IP3 and Ca(2+). The subsequent release of Ca(2+) from intracellular stores activated the protein phosphatase cascade involving calcineurin and protein phosphatase 1. The activation of purinergic P2Y(1) receptors blocked LTD. This effect was prevented by P2Y(1) receptor antagonists and was absent in mice lacking P2Y(1) but not P2Y(2) receptors. We also found that activation of P2Y(1) receptors inhibits Ca(2+) transients via VSCCs in the apical dendrites and spines of pyramidal neurons. In addition, we show that the release of ATP under hypoxia is able to inhibit LTD by acting on postsynaptic P2Y(1) receptors. In conclusion, these data suggest that the reduction of Ca(2+) influx via VSCCs caused by the activation of P2Y(1) receptors by ATP is the possible mechanism for the inhibition of LTD in prefrontal cortex.
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Affiliation(s)
- Segundo J Guzman
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany.
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Stadler F, Schmutz I, Schwaller B, Albrecht U. Lack of calbindin-D28k alters response of the murine circadian clock to light. Chronobiol Int 2010; 27:68-82. [PMID: 20205558 DOI: 10.3109/07420521003648554] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A strong stimulus adjusting the circadian clock to the prevailing light-dark cycle is light. However, the circadian clock is reset by light only at specific times of the day. The mechanisms mediating such gating of light input to the CNS are not well understood. There is evidence that Ca(2+) ions play an important role in intracellular signaling mechanisms, including signaling cascades stimulated by light. Therefore, Ca(2+) is hypothesized to play a role in the light-mediated resetting of the circadian clock. Calbindin-D28k (CB; gene symbol: Calb1) is a Ca(2+) binding protein implicated in Ca(2+) homeostasis and sensing. The absence of this protein influences Ca(2+) buffering capacity of a cell, alters spatio-temporal aspects of intracellular Ca(2+) signaling, and hence might alter transmission of light information to the circadian clock in neurons of the suprachiasmatic nuclei (SCN). We tested mice lacking a functional Calb1 gene (Calb1(-/-)) and found an increased phase-delay response to light applied at circadian time (CT) 14 in these animals. This is accompanied by elevated induction of Per2 gene expression in the SCN. Period length and circadian rhythmicity were comparable between Calb1(-/-) and wild-type animals. Our findings indicate an involvement of CB in the signaling pathway that modulates the behavioral and molecular response to light.
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Affiliation(s)
- Frédéric Stadler
- Department of Medicine, Unit of Biochemistry, University of Fribourg, 1700 Fribourg, Switzerland
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