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Kovács Z, Skatchkov SN, Veh RW, Szabó Z, Németh K, Szabó PT, Kardos J, Héja L. Critical Role of Astrocytic Polyamine and GABA Metabolism in Epileptogenesis. Front Cell Neurosci 2022; 15:787319. [PMID: 35069115 PMCID: PMC8770812 DOI: 10.3389/fncel.2021.787319] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/09/2021] [Indexed: 12/22/2022] Open
Abstract
Accumulating evidence indicate that astrocytes are essential players of the excitatory and inhibitory signaling during normal and epileptiform activity via uptake and release of gliotransmitters, ions, and other substances. Polyamines can be regarded as gliotransmitters since they are almost exclusively stored in astrocytes and can be released by various mechanisms. The polyamine putrescine (PUT) is utilized to synthesize GABA, which can also be released from astrocytes and provide tonic inhibition on neurons. The polyamine spermine (SPM), synthesized form PUT through spermidine (SPD), is known to unblock astrocytic Cx43 gap junction channels and therefore facilitate astrocytic synchronization. In addition, SPM released from astrocytes may also modulate neuronal NMDA, AMPA, and kainate receptors. As a consequence, astrocytic polyamines possess the capability to significantly modulate epileptiform activity. In this study, we investigated different steps in polyamine metabolism and coupled GABA release to assess their potential to control seizure generation and maintenance in two different epilepsy models: the low-[Mg2+] model of temporal lobe epilepsy in vitro and in the WAG/Rij rat model of absence epilepsy in vivo. We show that SPM is a gliotransmitter that is released from astrocytes and significantly contributes to network excitation. Importantly, we found that inhibition of SPD synthesis completely prevented seizure generation in WAG/Rij rats. We hypothesize that this antiepileptic effect is attributed to the subsequent enhancement of PUT to GABA conversion in astrocytes, leading to GABA release through GAT-2/3 transporters. This interpretation is supported by the observation that antiepileptic potential of the Food and Drug Administration (FDA)-approved drug levetiracetam can be diminished by specifically blocking astrocytic GAT-2/3 with SNAP-5114, suggesting that levetiracetam exerts its effect by increasing surface expression of GAT-2/3. Our findings conclusively suggest that the major pathway through which astrocytic polyamines contribute to epileptiform activity is the production of GABA. Modulation of astrocytic polyamine levels, therefore, may serve for a more effective antiepileptic drug development in the future.
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Affiliation(s)
- Zsolt Kovács
- Department of Biology, ELTE Eötvös Loránd University, Savaria University Centre, Szombathely, Hungary
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central Del Caribe, Bayamon, PR, United States
- Department of Biochemistry, Universidad Central Del Caribe, Bayamon, PR, United States
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Centrum 2, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Krisztina Németh
- MS Metabolomics Research Group, Centre for Structural Study, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Pál T. Szabó
- MS Metabolomics Research Group, Centre for Structural Study, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
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Arginase and Arginine Decarboxylase - Where Do the Putative Gate Keepers of Polyamine Synthesis Reside in Rat Brain? PLoS One 2013; 8:e66735. [PMID: 23840524 PMCID: PMC3686689 DOI: 10.1371/journal.pone.0066735] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/09/2013] [Indexed: 12/17/2022] Open
Abstract
Polyamines are important regulators of basal cellular functions but also subserve highly specific tasks in the mammalian brain. With this respect, polyamines and the synthesizing and degrading enzymes are clearly differentially distributed in neurons versus glial cells and also in different brain areas. The synthesis of the diamine putrescine may be driven via two different pathways. In the “classical” pathway urea and carbon dioxide are removed from arginine by arginase and ornithine decarboxylase. The alternative pathway, first removing carbon dioxide by arginine decarboxlyase and then urea by agmatinase, may serve the same purpose. Furthermore, the intermediate product of the alternative pathway, agmatine, is an endogenous ligand for imidazoline receptors and may serve as a neurotransmitter. In order to evaluate and compare the expression patterns of the two gate keeper enzymes arginase and arginine decarboxylase, we generated polyclonal, monospecific antibodies against arginase-1 and arginine decarboxylase. Using these tools, we immunocytochemically screened the rat brain and compared the expression patterns of both enzymes in several brain areas on the regional, cellular and subcellular level. In contrast to other enzymes of the polyamine pathway, arginine decarboxylase and arginase are both constitutively and widely expressed in rat brain neurons. In cerebral cortex and hippocampus, principal neurons and putative interneurons were clearly labeled for both enzymes. Labeling, however, was strikingly different in these neurons with respect to the subcellular localization of the enzymes. While with antibodies against arginine decarboxylase the immunosignal was distributed throughout the cytoplasm, arginase-like immunoreactivity was preferentially localized to Golgi stacks. Given the apparent congruence of arginase and arginine decarboxylase distribution with respect to certain cell populations, it seems likely that the synthesis of agmatine rather than putrescine may be the main purpose of the alternative pathway of polyamine synthesis, while the classical pathway supplies putrescine and spermidine/spermine in these neurons.
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Yang M, Carbó Tano M, Freudenthal R, Hermitte G. Characterization of the cardiac ganglion in the crab Neohelice granulata and immunohistochemical evidence of GABA-like extrinsic regulation. ARTHROPOD STRUCTURE & DEVELOPMENT 2013; 42:17-25. [PMID: 22986313 DOI: 10.1016/j.asd.2012.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 07/18/2012] [Accepted: 09/09/2012] [Indexed: 06/01/2023]
Abstract
The aim of the present work is to provide an anatomical description of the cardiac system in the crab Neohelice granulata and evidence of the presence of GABA by means of immunohistochemistry. The ganglionic trunk was found lying on the inner surface of the heart's dorsal wall. After dissection, this structure appeared as a Y-shaped figure with its major axis perpendicular to the major axis of the heart. Inside the cardiac ganglion, we identified four large neurons of 63.7 μm ± 3.7 in maximum diameter, which were similar to the motor neurons described in other decapods. All the GABA-like immunoreactivity (GABAi) was observed as processes entering mainly the ganglionic trunk and branching in slender varicose fibers, forming a network around the large neurons suggesting that GABAi processes contact them. Our findings strengthen previous results suggesting that the GABAergic system mediates the cardio-inhibitory response upon sensory stimulation.
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Affiliation(s)
- Margarita Yang
- Laboratorio de Neurobiología de la Memoria, IFIByNE-CONICET, Departamento de Fisiología Biología Molecular y Celular, Universidad de Buenos Aires, Buenos Aires, Argentina
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Huisman H, Wynveen P, Nichkova M, Kellermann G. Novel ELISAs for Screening of the Biogenic Amines GABA, Glycine, β-Phenylethylamine, Agmatine, and Taurine Using One Derivatization Procedure of Whole Urine Samples. Anal Chem 2010; 82:6526-33. [DOI: 10.1021/ac100858u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Han Huisman
- Pharmasan Laboratories Inc., Department of Research and Development, 375, 280th Street Osceola, Wisconsin 54020, and NeuroScience Inc., 375, 280th Street Osceola, Wisconsin 54020
| | - Paul Wynveen
- Pharmasan Laboratories Inc., Department of Research and Development, 375, 280th Street Osceola, Wisconsin 54020, and NeuroScience Inc., 375, 280th Street Osceola, Wisconsin 54020
| | - Mikaela Nichkova
- Pharmasan Laboratories Inc., Department of Research and Development, 375, 280th Street Osceola, Wisconsin 54020, and NeuroScience Inc., 375, 280th Street Osceola, Wisconsin 54020
| | - Gottfried Kellermann
- Pharmasan Laboratories Inc., Department of Research and Development, 375, 280th Street Osceola, Wisconsin 54020, and NeuroScience Inc., 375, 280th Street Osceola, Wisconsin 54020
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Huisman H, Wynveen P, Setter PW. Studies on the immune response and preparation of antibodies against a large panel of conjugated neurotransmitters and biogenic amines: specific polyclonal antibody response and tolerance. J Neurochem 2010; 112:829-41. [DOI: 10.1111/j.1471-4159.2009.06492.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Jin N, Kolliputi N, Gou D, Weng T, Liu L. A novel function of ionotropic gamma-aminobutyric acid receptors involving alveolar fluid homeostasis. J Biol Chem 2006; 281:36012-20. [PMID: 17003036 DOI: 10.1074/jbc.m606895200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polarized distribution of chloride channels on the plasma membrane of epithelial cells is required for fluid transport across the epithelium of fluid-transporting organs. Ionotropic gamma-aminobutyric acid receptors are primary ligand-gated chloride channels that mediate inhibitory neurotransmission. Traditionally, these receptors are not considered to be contributors to fluid transport. Here, we report a novel function of gamma-aminobutyric acid receptors involving alveolar fluid homeostasis in adult lungs. We demonstrated the expression of functional ionotropic gamma-aminobutyric acid receptors on the apical plasma membrane of alveolar epithelial type II cells. gamma-Aminobutyric acid significantly increased chloride efflux in the isolated type II cells and inhibited apical to basolateral chloride transport on type II cell monolayers. Reduction of the gamma-aminobutyric acid receptor pi subunit using RNA interference abolished the gamma-aminobutyric acid-mediated chloride transport. In intact rat lungs, gamma-aminobutyric acid inhibited both basal and beta agonist-stimulated alveolar fluid clearance. Thus, we provide molecular and pharmacological evidence that ionotropic gamma-aminobutyric acid receptors contribute to fluid transport in the lung via luminal secretion of chloride. This finding may have the potential to develop clinical approaches for pulmonary diseases involving abnormal fluid dynamics.
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Affiliation(s)
- Nili Jin
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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Rosenquist C, Fledelius C, Christgau S, Pedersen BJ, Bonde M, Qvist P, Christiansen C. Serum CrossLaps One Step ELISA. First application of monoclonal antibodies for measurement in serum of bone-related degradation products from C-terminal telopeptides of type I collagen. Clin Chem 1998. [DOI: 10.1093/clinchem/44.11.2281] [Citation(s) in RCA: 235] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
We have developed a two-site ELISA for measurement in serum of bone-related degradation products derived from C-terminal telopeptides of type I collagen. The assay is based on the application of two highly specific monoclonal antibodies against the amino acid sequence of AHD-β-GGR, where the aspartic acid residue (D) is β-isomerized. In a one-step incubation procedure, the degradation products containing cross-linked diisomerized EKAHD-β-GGR peptides are captured by a biotinylated antibody and a peroxidase-conjugated antibody. The generated complex is then bound to the streptavidin surface via the biotin conjugate. Desalted urinary antigens are used for standardization, and parallelism is observed with serum samples. Results are obtained in <2.5 h, and both inter- and intraassay imprecision are <8%. The serum CrossLaps™ concentration was 1748 ± 740 pmol/L (mean ± SD) in premenopausal women (n = 65) and 2952 ± 1325 pmol/L in a group of healthy postmenopausal women (n = 169). The Serum CrossLaps One Step ELISA was capable of detecting a highly significant (P <0.001) effect of hormone replacement therapy in a retrospective study involving 22 postmenopausal women.
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Affiliation(s)
- Christian Rosenquist
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Christian Fledelius
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Stephan Christgau
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Brian J Pedersen
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Martin Bonde
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Per Qvist
- Osteometer BioTech A/S, Osteopark, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Claus Christiansen
- Center for Clinical and Basic Research, Ballerup Byvej 222, DK-2750 Ballerup, Denmark
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Biedermann B, Skatchkov SN, Brunk I, Bringmann A, Pannicke T, Bernstein HG, Faude F, Germer A, Veh R, Reichenbach A. Spermine/spermidine is expressed by retinal glial (Müller) cells and controls distinct K+ channels of their membrane. Glia 1998; 23:209-20. [PMID: 9633806 DOI: 10.1002/(sici)1098-1136(199807)23:3<209::aid-glia4>3.0.co;2-#] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is recent evidence that polyamines such as spermine (spm) and spermidine (spd) may act as endogenous modulators of the activity of inwardly rectifying K+ channels. This type of K+ channels is abundantly expressed by retinal glial (Müller) cells where they are involved in important glial cell functions such as the clearance of excess extracellular K+ ions. This prompted us to study the following questions, i) do mammalian Müller cells contain endogenous spm/spd?; ii) do Müller cells possess the enzymes (e.g., ornithine decarboxylase, ODC) necessary to produce spm/spd?; and iii) does application of exogenous spm/spd exert specific effects onto inwardly rectifying K+ channels of Müller cells? Immunocytochemical studies were performed on histological sections of guinea-pig, rabbit, porcine, and human retinae, and on enzymatically dissociated Müller cells. Whole-cell and patch-clamp recordings were performed on enzymatically dissociated porcine and guinea-pig Müller cells. All above-mentioned questions could be answered with "yes." Specifically, the majority of Müller cells were labeled with antibodies directed to spm/spd, both within retinal sections and enzymatically isolated from retinal tissue. Müller cells in normal retinae express low levels of ODC but increase this expression markedly in cases of retinal pathology such as experimental epiretinal melanoma. Externally applied polyamines (1 mM) reduce (predominantly inward) whole-cell K+ currents, with the efficacies being spm > spd > put. If applied at the inside of membrane patches, spm (1 mM) blocks completely the outward currents through inwardly rectifying K+ channels but fails to affect the activity of large conductance, Ca2+-activated K+ channels. It is concluded that Müller cells contain endogenous channel-active polyamines, the synthesis of which may be up-regulated in pathological situations, and which may be involved in the control of both glial function and cell proliferation.
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Affiliation(s)
- B Biedermann
- Paul Flechsig Institute for Brain Research, Leipzig University, Germany
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Abstract
Polyamines are involved in a variety of basic cellular functions including proliferation and differentiation. Recent in vitro evidence suggests a role for spermidine or spermine as possible modulators of ionotropic glutamate receptors and inwardly rectifying potassium channels. However, before a functional role of spermidine or spermine in vivo can be considered, the presence of these polyamines in the mammalian central nervous system must be demonstrated. Here we report the localization of spermine/spermidine-like immunoreactivity in the major cell types of the adult rat brain, using polyclonal antibodies raised against glutaraldehyde-conjugated spermine. Neuronal staining was restricted to several discrete brain nuclei and was generally weak. In the hippocampus, immunoreactivity was found in the area of perforant path terminals and in the CA2/CA3 subfields. The CA1 region and the area of the mossy fiber terminals was largely negative. Throughout the brain, the most prominent staining was displayed by astrocytes, as confirmed by comparison with astrocyte and microglial markers, but immunolabel was also detected in oligodendrocytes and pericytes. Their intense staining for spermidine/spermine-like immunoreactivity suggests that astrocytes are the most likely source for extracellular polyamines in the rat brain.
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Affiliation(s)
- G Laube
- Zentrum für Molekulare Neurobiologie, Institut für Neurale Signalverarbeitung, Universität Hamburg, Federal Republic of Germany
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Fledelius C, Kolding I, Qvist P, Bonde M, Hassager C, Reginster JY, Hejgaard J, Frøokiaer H, Christiansen C. Development of a monoclonal antibody to urinary degradation products from the C-terminal telopeptide alpha 1 chain of type I collagen. Application in an enzyme immunoassay and comparison to CrossLaps ELISA. Scand J Clin Lab Invest 1997; 57:73-83. [PMID: 9127460 DOI: 10.1080/00365519709057821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A monoclonal antibody MAbA7 was raised against a synthetic peptide having a sequence (EKAHDGGR) specific for a part of the C-telopeptide alpha 1 chain of type I collagen. MAbA7 was labelled with horseradish peroxide and used in a competitive one-step enzyme-linked immunosorbent assay (ELISA) for measurement of urinary type I collagen degradation products. The assay was technically evaluated and preliminary clinical data are presented. The measuring range was 200-7000 micrograms l-1 with a detection limit of 25 micrograms l-1. Within-run and total CVs were 5.5 and 8.0%, respectively. Analytical recovery averaged 96.6% +/- 5.3 (mean +/- 1SD). Values obtained in the ELISA were highly correlated (r = 0.93) to values obtained by a commercially available assay (CrossLaps ELISA) known to measure urinary degradation products derived from the C-telopeptide of type I collagen reflecting the rate of bone resorption. Investigation of the urinary fragments responsible for the immunological response in the two assays revealed, however, that they are not identical. Values obtained in urine samples from postmenopausal women (n = 108) and patients with Paget's disease (n = 6) increased 43% (p < 0.01) and 28-fold (p < 0.001), respectively, when compared to a premenopausal level (n = 50). A decrease in the urinary concentrations of 67% (p < 0.01) was seen after 6 months in urine samples from postmenopausal women (n = 13) receiving hormone replacement therapy (HRT) compared to a group receiving placebo (n = 9). Likewise, the urinary concentrations decreased 88% (p < 0.001) in early postmenopausal women receiving bisphosphonate therapy (n = 11) for a period of 9 months compared to a group receiving placebo (n = 12). These results suggest that the monoclonal antibody and the new assay may be useful for further investigations of the physiological and clinical importance of type I collagen degradation.
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Veh RW, Lichtinghagen R, Sewing S, Wunder F, Grumbach IM, Pongs O. Immunohistochemical localization of five members of the Kv1 channel subunits: contrasting subcellular locations and neuron-specific co-localizations in rat brain. Eur J Neurosci 1995; 7:2189-205. [PMID: 8563969 DOI: 10.1111/j.1460-9568.1995.tb00641.x] [Citation(s) in RCA: 270] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A large variety of potassium channels is involved in regulating integration and transmission of electrical signals in the nervous system. Different types of neurons, therefore, require specific patterns of potassium channel subunits expression and specific regulation of subunit coassembly into heteromultimeric channels, as well as subunit-specific sorting and segregation. This was investigated by studying in detail the expression of six different alpha-subunits of voltage-gated potassium channels in the rat hippocampus, cerebellum, olfactory bulb and spinal cord, combining in situ hybridization and immunocytochemistry. Specific polyclonal antibodies were prepared for five alpha-subunits (Kv1.1, Kv1.2, Kv1.3 Kv1.4, Kv1.6) of the Shaker-related subfamily of rat Kv channels, which encode delayed-rectifier type and rapidly inactivating A-type potassium channels. Their distribution was compared to that of an A-type potassium channel (Kv3.4), belonging to the Shaw-related subfamily of rat Kv channels. Our results show that these Kv channel alpha-subunits are differentially expressed in rat brain neurons. We did not observe in various neurons a stereotypical distribution of Kv channel alpha-subunits to dendritic and axonal compartments, but a complex differential subcellular subunit distribution. The different Kv channel subunits are targeted either to presynaptic or to postsynaptic domains, depending on neuronal cell type. Thus, distinct combinations of Kv1 alpha-subunits are co-localized in different neurons. The implications of these findings are that both differential expression and assembly as well as subcellular targeting of Kv channel alpha-subunits may contribute to Kv channel diversity and thereby to presynaptic and postsynaptic membrane excitability.
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Affiliation(s)
- R W Veh
- Institut für neurale Signalverarbeitung, Zentrum für Molekulare Neurobiologie, Hamburg, Germany
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Redecker P, Veh RW. Glutamate immunoreactivity is enriched over pinealocytes of the gerbil pineal gland. Cell Tissue Res 1994; 278:579-88. [PMID: 7850868 DOI: 10.1007/bf00331377] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mammalian pinealocytes have been shown to contain synaptic-like microvesicles with putative secretory functions. As a first step to elucidate the possibility that pinealocyte microvesicles store messenger molecules, such as neuroactive amino acids, we have studied the distributional pattern of glutamate immunoreactivity in the pineal gland of the Mongolian gerbil (Meriones unguiculatus) at both light- and electron-microscopic levels. In semithin sections of plastic-embedded pineals, strong glutamate immunoreactivity could be detected in pinealocytes throughout the pineal gland. The density of glutamate immunolabeling in pinealocytes varied among individual cells and was mostly paralleled by the density of immunostaining for synaptophysin, a major integral membrane protein of synaptic and synaptic-like vesicles. Postembedding immunogold staining of ultrathin pineal sections revealed that gold particles were enriched over pinealocytes. In particular, a high degree of immunoreactivity was associated with accumulations of microvesicles that filled dilated process terminals of pinealocytes. A positive correlation between the number of gold particles and the packing density of microvesicles was found in three out of four process terminals analyzed. However, the level of glutamate immunoreactivity in pinealocyte process endings was lower than in presumed glutamatergic nerve terminals of the cerebellum and posterior pituitary. The present results provide some evidence for a microvesicular compartmentation of glutamate in pinealocytes. Our findings thus lend support to the hypothesis that glutamate serves as an intrapineal signal molecule of physiological relevance to the neuroendocrine functions of the gland.
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Affiliation(s)
- P Redecker
- Abteilung Anatomie 1, Medizinische Hochschule Hannover, Germany
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Fatima B, Hugues G, Giampiero B, Alain B, Pascal B, Dontenwill M. Polyclonal anti-idazoxan antibodies: characterization and purification. Eur J Pharmacol 1993; 246:45-51. [PMID: 8354342 DOI: 10.1016/0922-4106(93)90008-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Amino-idazoxan coupled to hemocyanine was used to raise anti-idazoxan antibodies in the rabbit. The antibodies were affinity purified with an amino-idazoxan affinity column. Binding studies with [3H]idazoxan showed a dissociation constant of 2.2 +/- 1.4 nM. The specificity spectrum of these antibodies indicates that the imidazoline part of idazoxan is more important for recognition than the benzodioxan ring as imidazoline substances (clonidine, cirazoline) are powerful competitors of [3H]idazoxan binding on the antibodies. Catecholamines or imidazoles were unable to displace [3H]idazoxan from the antibodies. These anti-idazoxan antibodies present specificity similarities with the imidazoline receptor as did our previously obtained anti-clonidine antibodies. Affinity-purified antibodies represent useful tools for studying the imidazoline receptors particularly with an anti-idiotypic approach.
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Affiliation(s)
- B Fatima
- Laboratoire de Pharmacologie Cardiovasculaire et Rénale, CNRS URA, Faculté de Médecine, Strasbourg, France
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Neuropeptide Conjugation to Carrier Proteins. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/b978-0-12-185275-7.50025-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Drenckhahn D, Jöns T, Schmitz F. Production of polyclonal antibodies against proteins and peptides. Methods Cell Biol 1993; 37:7-56. [PMID: 8255251 DOI: 10.1016/s0091-679x(08)60242-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- D Drenckhahn
- Department of Anatomy, Julius-Maximilians University, Würzburg, Germany
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