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Tzilivaki A, Tukker JJ, Maier N, Poirazi P, Sammons RP, Schmitz D. Hippocampal GABAergic interneurons and memory. Neuron 2023; 111:3154-3175. [PMID: 37467748 PMCID: PMC10593603 DOI: 10.1016/j.neuron.2023.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/04/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023]
Abstract
One of the most captivating questions in neuroscience revolves around the brain's ability to efficiently and durably capture and store information. It must process continuous input from sensory organs while also encoding memories that can persist throughout a lifetime. What are the cellular-, subcellular-, and network-level mechanisms that underlie this remarkable capacity for long-term information storage? Furthermore, what contributions do distinct types of GABAergic interneurons make to this process? As the hippocampus plays a pivotal role in memory, our review focuses on three aspects: (1) delineation of hippocampal interneuron types and their connectivity, (2) interneuron plasticity, and (3) activity patterns of interneurons during memory-related rhythms, including the role of long-range interneurons and disinhibition. We explore how these three elements, together showcasing the remarkable diversity of inhibitory circuits, shape the processing of memories in the hippocampus.
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Affiliation(s)
- Alexandra Tzilivaki
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; Einstein Center for Neurosciences, Chariteplatz 1, 10117 Berlin, Germany; NeuroCure Cluster of Excellence, Chariteplatz 1, 10117 Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Nikolaus Maier
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany
| | - Panayiota Poirazi
- Foundation for Research and Technology Hellas (FORTH), Institute of Molecular Biology and Biotechnology (IMBB), N. Plastira 100, Heraklion, Crete, Greece
| | - Rosanna P Sammons
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; Einstein Center for Neurosciences, Chariteplatz 1, 10117 Berlin, Germany; NeuroCure Cluster of Excellence, Chariteplatz 1, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany; Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Philippstrasse. 13, 10115 Berlin, Germany; Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Straße 10, 13125 Berlin, Germany.
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2
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Tukker JJ. How I learned to redefine academic success as a senior postdoc. eLife 2022; 11:83251. [PMID: 36222301 PMCID: PMC9555857 DOI: 10.7554/elife.83251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
After many professional twists and turns, a researcher in his forties reconsiders what it means to 'make it' in science.
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Affiliation(s)
- John J Tukker
- German Center for Neurodegenerative Diseases (DZNE Berlin), Berlin, Germany
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3
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Abstract
The hippocampal formation is critically involved in learning and memory and contains a large proportion of neurons encoding aspects of the organism’s spatial surroundings. In the medial entorhinal cortex (MEC), this includes grid cells with their distinctive hexagonal firing fields as well as a host of other functionally defined cell types including head direction cells, speed cells, border cells, and object-vector cells. Such spatial coding emerges from the processing of external inputs by local microcircuits. However, it remains unclear exactly how local microcircuits and their dynamics within the MEC contribute to spatial discharge patterns. In this review we focus on recent investigations of intrinsic MEC connectivity, which have started to describe and quantify both excitatory and inhibitory wiring in the superficial layers of the MEC. Although the picture is far from complete, it appears that these layers contain robust recurrent connectivity that could sustain the attractor dynamics posited to underlie grid pattern formation. These findings pave the way to a deeper understanding of the mechanisms underlying spatial navigation and memory.
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Affiliation(s)
- John J Tukker
- Network Dysfunction, German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Prateep Beed
- NeuroScientific Research Center, Charite Berlin, Germany
| | - Michael Brecht
- Systems Neuroscience, Humboldt University of Berlin, Berlin, Germany
| | - Richard Kempter
- Department of Biology, Institute for Theoretical Biology, Humbolt-Universität zu Berlin, Berlin, Germany
| | - Edvard I Moser
- Kavli Institute for Systems Neuroscience and Centre for the Biology of Memory, Norwegian University of Science and Technology
| | - Dietmar Schmitz
- Neuroscience Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
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4
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de Filippo R, Rost BR, Stumpf A, Cooper C, Tukker JJ, Harms C, Beed P, Schmitz D. Somatostatin interneurons activated by 5-HT 2A receptor suppress slow oscillations in medial entorhinal cortex. eLife 2021; 10:66960. [PMID: 33789079 PMCID: PMC8016478 DOI: 10.7554/elife.66960] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022] Open
Abstract
Serotonin (5-HT) is one of the major neuromodulators present in the mammalian brain and has been shown to play a role in multiple physiological processes. The mechanisms by which 5-HT modulates cortical network activity, however, are not yet fully understood. We investigated the effects of 5-HT on slow oscillations (SOs), a synchronized cortical network activity universally present across species. SOs are observed during anesthesia and are considered to be the default cortical activity pattern. We discovered that (±)3,4-methylenedioxymethamphetamine (MDMA) and fenfluramine, two potent 5-HT releasers, inhibit SOs within the entorhinal cortex (EC) in anesthetized mice. Combining opto- and pharmacogenetic manipulations with in vitro electrophysiological recordings, we uncovered that somatostatin-expressing (Sst) interneurons activated by the 5-HT2A receptor (5-HT2AR) play an important role in the suppression of SOs. Since 5-HT2AR signaling is involved in the etiology of different psychiatric disorders and mediates the psychological effects of many psychoactive serotonergic drugs, we propose that the newly discovered link between Sst interneurons and 5-HT will contribute to our understanding of these complex topics.
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Affiliation(s)
- Roberto de Filippo
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Cluster of Excellence NeuroCure, Berlin, Germany
| | - Benjamin R Rost
- German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Alexander Stumpf
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - Claire Cooper
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Christoph Harms
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Experimental Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Center for Stroke Research Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Neuroscience Research Center, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Cluster of Excellence NeuroCure, Berlin, Germany.,German Centre for Neurodegenerative Diseases (DZNE), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Einstein Center for Neurosciences Berlin, Berlin, Germany
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5
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Tukker JJ, Beed P, Schmitz D, Larkum ME, Sachdev RNS. Up and Down States and Memory Consolidation Across Somatosensory, Entorhinal, and Hippocampal Cortices. Front Syst Neurosci 2020; 14:22. [PMID: 32457582 PMCID: PMC7227438 DOI: 10.3389/fnsys.2020.00022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 01/01/2023] Open
Abstract
In the course of a day, brain states fluctuate, from conscious awake information-acquiring states to sleep states, during which previously acquired information is further processed and stored as memories. One hypothesis is that memories are consolidated and stored during "offline" states such as sleep, a process thought to involve transfer of information from the hippocampus to other cortical areas. Up and Down states (UDS), patterns of activity that occur under anesthesia and sleep states, are likely to play a role in this process, although the nature of this role remains unclear. Here we review what is currently known about these mechanisms in three anatomically distinct but interconnected cortical areas: somatosensory cortex, entorhinal cortex, and the hippocampus. In doing so, we consider the role of this activity in the coordination of "replay" during sleep states, particularly during hippocampal sharp-wave ripples. We conclude that understanding the generation and propagation of UDS may provide key insights into the cortico-hippocampal dialogue linking archi- and neocortical areas during memory formation.
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Affiliation(s)
- John J Tukker
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Neuroscience Research Center, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Cluster of Excellence NeuroCure, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany
| | - Matthew E Larkum
- Cluster of Excellence NeuroCure, Berlin, Germany.,Einstein Center for Neurosciences Berlin, Berlin, Germany.,Institut für Biologie, Humboldt Universität, Berlin, Germany
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6
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Nitzan N, McKenzie S, Beed P, English DF, Oldani S, Tukker JJ, Buzsáki G, Schmitz D. Propagation of hippocampal ripples to the neocortex by way of a subiculum-retrosplenial pathway. Nat Commun 2020; 11:1947. [PMID: 32327634 PMCID: PMC7181800 DOI: 10.1038/s41467-020-15787-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 03/27/2020] [Indexed: 02/07/2023] Open
Abstract
Bouts of high frequency activity known as sharp wave ripples (SPW-Rs) facilitate communication between the hippocampus and neocortex. However, the paths and mechanisms by which SPW-Rs broadcast their content are not well understood. Due to its anatomical positioning, the granular retrosplenial cortex (gRSC) may be a bridge for this hippocampo-cortical dialogue. Using silicon probe recordings in awake, head-fixed mice, we show the existence of SPW-R analogues in gRSC and demonstrate their coupling to hippocampal SPW-Rs. gRSC neurons reliably distinguished different subclasses of hippocampal SPW-Rs according to ensemble activity patterns in CA1. We demonstrate that this coupling is brain state-dependent, and delineate a topographically-organized anatomical pathway via VGlut2-expressing, bursty neurons in the subiculum. Optogenetic stimulation or inhibition of bursty subicular cells induced or reduced responses in superficial gRSC, respectively. These results identify a specific path and underlying mechanisms by which the hippocampus can convey neuronal content to the neocortex during SPW-Rs.
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Affiliation(s)
- Noam Nitzan
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
| | - Sam McKenzie
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
| | - Daniel Fine English
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA
- School of Neuroscience, College of Science, Virginia Tech, VA, 24061, USA
| | - Silvia Oldani
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - György Buzsáki
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA.
- Center for Neural Science, New York University, New York, NY, 10016, USA.
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany.
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
- Cluster of Excellence NeuroCure, Berlin, Germany.
- Einstein Center for Neurosciences, Berlin, Germany.
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7
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Starossom SC, Campo Garcia J, Woelfle T, Romero-Suarez S, Olah M, Watanabe F, Cao L, Yeste A, Tukker JJ, Quintana FJ, Imitola J, Witzel F, Schmitz D, Morkel M, Paul F, Infante-Duarte C, Khoury SJ. Chi3l3 induces oligodendrogenesis in an experimental model of autoimmune neuroinflammation. Nat Commun 2019; 10:217. [PMID: 30644388 PMCID: PMC6333780 DOI: 10.1038/s41467-018-08140-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/18/2018] [Indexed: 01/19/2023] Open
Abstract
In demyelinating diseases including multiple sclerosis (MS), neural stem cells (NSCs) can replace damaged oligodendrocytes if the local microenvironment supports the required differentiation process. Although chitinase-like proteins (CLPs) form part of this microenvironment, their function in this differentiation process is unknown. Here, we demonstrate that murine Chitinase 3-like-3 (Chi3l3/Ym1), human Chi3L1 and Chit1 induce oligodendrogenesis. In mice, Chi3l3 is highly expressed in the subventricular zone, a stem cell niche of the adult brain, and in inflammatory brain lesions during experimental autoimmune encephalomyelitis (EAE). We find that silencing Chi3l3 increases severity of EAE. We present evidence that in NSCs Chi3l3 activates the epidermal growth factor receptor (EGFR), thereby inducing Pyk2-and Erk1/2- dependent expression of a pro-oligodendrogenic transcription factor signature. Our results implicate CLP-EGFR-Pyk2-MEK-ERK as a key intrinsic pathway controlling oligodendrogenesis.
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Affiliation(s)
- Sarah C Starossom
- Institute for Medical Immunology, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany.
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Berlin, Germany.
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany.
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Juliana Campo Garcia
- Institute for Medical Immunology, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Tim Woelfle
- Institute for Medical Immunology, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Silvina Romero-Suarez
- Institute for Medical Immunology, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Marta Olah
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Fumihiro Watanabe
- Laboratory of Neural Stem Cells and Functional Neurogenetics, Department of Neurology-The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Li Cao
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ada Yeste
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - John J Tukker
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
- DZNE-German Center for Neurodegenerative Diseases, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Francisco J Quintana
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jaime Imitola
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Neural Stem Cells and Functional Neurogenetics, Department of Neurology-The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Franziska Witzel
- IRI Life Sciences, Institute of Pathology, Computational Modeling in Medicine, Charité- Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Dietmar Schmitz
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
- IRI Life Sciences, Institute of Pathology, Computational Modeling in Medicine, Charité- Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Markus Morkel
- Institute of Pathology, Laboratory of Molecular Tumor Pathology and Systems Biology, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité - Universitätsmedizin Berlin, Berlin, Germany
- NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
- Department of Neurology, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Carmen Infante-Duarte
- Institute for Medical Immunology, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Samia J Khoury
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Abu Haidar Neuroscience Institute, American University of Beirut Medical Center, Beirut, Lebanon
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8
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Viney TJ, Lasztoczi B, Katona L, Crump MG, Tukker JJ, Klausberger T, Somogyi P. Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo. Nat Neurosci 2013; 16:1802-1811. [PMID: 24141313 DOI: 10.1038/nn.3550] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 09/18/2013] [Indexed: 11/09/2022]
Abstract
Hippocampal sharp waves are population discharges initiated by an unknown mechanism in pyramidal cell networks of CA3. Axo-axonic cells (AACs) regulate action potential generation through GABAergic synapses on the axon initial segment. We found that CA3 AACs in anesthetized rats and AACs in freely moving rats stopped firing during sharp waves, when pyramidal cells fire most. AACs fired strongly and rhythmically around the peak of theta oscillations, when pyramidal cells fire at low probability. Distinguishing AACs from other parvalbumin-expressing interneurons by their lack of detectable SATB1 transcription factor immunoreactivity, we discovered a somatic GABAergic input originating from the medial septum that preferentially targets AACs. We recorded septo-hippocampal GABAergic cells that were activated during hippocampal sharp waves and projected to CA3. We hypothesize that inhibition of AACs, and the resulting subcellular redistribution of inhibition from the axon initial segment to other pyramidal cell domains, is a necessary condition for the emergence of sharp waves promoting memory consolidation.
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Affiliation(s)
- Tim J Viney
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Balint Lasztoczi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Linda Katona
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Michael G Crump
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - John J Tukker
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK
| | - Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Peter Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Oxford, UK.,Center for Brain Research, Medical University Vienna, Vienna, Austria
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9
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Herfst L, Burgalossi A, Haskic K, Tukker JJ, Schmidt M, Brecht M. Friction-based stabilization of juxtacellular recordings in freely moving rats. J Neurophysiol 2012; 108:697-707. [PMID: 22514297 DOI: 10.1152/jn.00910.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Virtually nothing is known about the activity of morphologically identified neurons in freely moving mammals. Here we describe stabilization and positioning techniques that allow juxtacellular recordings from labeled single neurons in awake, freely moving animals. This method involves the use of a friction-based device that allows stabilization of the recording pipette by friction forces. Friction is generated by a clamplike mechanism that tightens a sliding pipette holder to a preimplanted pipette guide. The interacting surfaces are smoothed to optical quality (<5-nm roughness) to enable micrometer stepping precision of the device during operation. Our method allows recordings from identified neurons in freely moving animals, and thus opens new perspectives for analyzing the role of identified neurons in the control of behavior.
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Affiliation(s)
- Lucas Herfst
- Bernstein Center for Computational Neuroscience, Humboldt University of Berlin, Berlin, Germany
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10
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Affiliation(s)
- AJ King
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2 4GJ, UK
| | - JJ Tukker
- Department of Pharmaceutics, University of Utrecht, Netherlands
| | - C Marriott
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2 4GJ, UK
| | - GP Martin
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2 4GJ, UK
| | - D C Taylor
- Pnarmaceutical Department, ICI Pharmaceutical Division, Alderley Park, Macclesfield, UK
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11
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Lehr CM, Bouwstra JA, Kok W, De Boer AG, Tukker JJ, Verhoef JC, Breimer DD, Junginger HE. Effects of the Mucoadhesive Polymer Polycarbophil on the Intestinal Absorption of a Peptide Drug in the Rat. J Pharm Pharmacol 2011; 44:402-7. [PMID: 1359054 DOI: 10.1111/j.2042-7158.1992.tb03633.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
The absorption across rat intestinal tissue of the model peptide drug 9-desglycinamide, 8-arginine vasopressin from bioadhesive formulations was studied in-vitro, in a chronically isolated internal loop in-situ and after intraduodenal administration in-vivo. A controlled-release bioadhesive drug delivery system was tested, consisting of microspheres of poly(2-hydroxyethyl methacrylate) with a mucoadhesive Polycarbophil-coating, as well as a fast-release formulation consisting of an aqueous solution of the peptide in a suspension of Polycarbophil particles. Using the controlled-release system, a slight improvement of peptide absorption was found in-vitro in comparison with a non-adhesive control system, but not in-situ or in-vivo. In contrast, bioavailability was significantly increased in all three models from the Polycarbophil suspension in comparison with a solution of the drug in saline. The effect appeared to be dose-dependent, indicative of intrinsic penetration-enhancing properties of the mucoadhesive polymer. A prolongation of the absorption phase in-vitro and in the chronically isolated loop in-situ suggested that the polymer was able to protect the peptide from proteolytic degradation. This could be confirmed by degradation studies in-vitro. The duration of the penetration enhancing/enzyme inhibiting effect was diminished with increasing complexity of the test model, in the same way as was previously found for the bioadhesive effect. This interrelationship suggests that the observed improvement in peptide absorption and the mucoadhesive properties of this polymer are associated. The development of a fast-release oral dosage form for peptide drugs on the basis of Polycarbophil appears to be possible.
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Affiliation(s)
- C M Lehr
- Center for Bio-Pharmaceutical Sciences, Leiden University, The Netherlands
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12
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Affiliation(s)
- A J King
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2-4GJ, UK
| | - JJ Tukker
- Department of Pharmaceutics, University of Utrecht, Netherlands
| | - C Marriott
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2-4GJ, UK
| | - G P Martin
- Pharmaceutical Sciences Research Group, Brighton Polytechnic, Brighton BN2-4GJ, UK
| | - D C Taylor
- Pharmaceutical Department, ICI Pharmaceutical Division, Alderley Park, Macclesfield, UK
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13
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Abstract
Cortical gamma oscillations contribute to cognitive processing and are thought to be supported by perisomatic-innervating GABAergic interneurons. We performed extracellular recordings of identified interneurons in the hippocampal CA1 area of anesthetized rats, revealing that the firing patterns of five distinct interneuron types are differentially correlated to spontaneous gamma oscillations. The firing of bistratified cells, which target dendrites of pyramidal cells coaligned with the glutamatergic input from hippocampal area CA3, is strongly phase locked to field gamma oscillations. Parvalbumin-expressing basket, axo-axonic, and cholecystokinin-expressing interneurons exhibit moderate gamma modulation, whereas the spike timing of distal dendrite-innervating oriens-lacunosum moleculare interneurons is not correlated to field gamma oscillations. Cholecystokinin-expressing interneurons fire earliest in the gamma cycle, a finding that is consistent with their suggested function of thresholding individual pyramidal cells. Furthermore, we show that field gamma amplitude correlates with interneuronal spike-timing precision and firing rate. Overall, our recordings suggest that gamma synchronization in vivo is assisted by temporal- and domain-specific GABAergic inputs to pyramidal cells and is initiated in pyramidal cell dendrites in addition to somata and axon initial segments.
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Affiliation(s)
- John J. Tukker
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Pablo Fuentealba
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Katja Hartwich
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
- Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Peter Somogyi
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
| | - Thomas Klausberger
- Medical Research Council Anatomical Neuropharmacology Unit, Oxford University, Oxford OX1 3TH, United Kingdom, and
- Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
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14
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Abstract
The starburst amacrine cell (SBAC), found in all mammalian retinas,
is thought to provide the directional inhibitory input recorded in
On–Off direction-selective ganglion cells (DSGCs). While voltage
recordings from the somas of SBACs have not shown robust direction
selectivity (DS), the dendritic tips of these cells display
direction-selective calcium signals, even when γ-aminobutyric acid
(GABAa,c) channels are blocked, implying that inhibition is
not necessary to generate DS. This suggested that the distinctive
morphology of the SBAC could generate a DS signal at the dendritic
tips, where most of its synaptic output is located. To explore this
possibility, we constructed a compartmental model incorporating
realistic morphological structure, passive membrane properties, and
excitatory inputs. We found robust DS at the dendritic tips but not at
the soma. Two-spot apparent motion and annulus radial motion produced
weak DS, but thin bars produced robust DS. For these stimuli, DS was
caused by the interaction of a local synaptic input signal with a
temporally delayed “global” signal, that is, an excitatory
postsynaptic potential (EPSP) that spread from the activated inputs
into the soma and throughout the dendritic tree. In the preferred
direction the signals in the dendritic tips coincided, allowing
summation, whereas in the null direction the local signal preceded the
global signal, preventing summation. Sine-wave grating stimuli produced
the greatest amount of DS, especially at high velocities and low
spatial frequencies. The sine-wave DS responses could be accounted for
by a simple mathematical model, which summed phase-shifted signals from
soma and dendritic tip. By testing different artificial morphologies,
we discovered DS was relatively independent of the morphological
details, but depended on having a sufficient number of inputs at the
distal tips and a limited electrotonic isolation. Adding voltage-gated
calcium channels to the model showed that their threshold effect can
amplify DS in the intracellular calcium signal.
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Affiliation(s)
- John J Tukker
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
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15
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Annaert P, Tukker JJ, van Gelder J, Naesens L, de Clercq E, van Den Mooter G, Kinget R, Augustijns P. In vitro, ex vivo, and in situ intestinal absorption characteristics of the antiviral ester prodrug adefovir dipivoxil. J Pharm Sci 2000; 89:1054-62. [PMID: 10906729 DOI: 10.1002/1520-6017(200008)89:8<1054::aid-jps10>3.0.co;2-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Caco-2 monolayers (in vitro), rat intestinal sheets mounted in modified Ussing Chambers (ex vivo), and in situ intestinal perfusion of rat ileum were used as models to determine and compare the absorption characteristics of the antiviral agent 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA, adefovir) and its bis(pivaloyloxymethyl)-ester prodrug [bis(POM)-PMEA, adefovir dipivoxil]. Although metabolism of adefovir dipivoxil was more pronounced in the ex vivo and in situ models than in the Caco-2 system, the transport of 'total adefovir' [= adefovir dipivoxil and its metabolites mono(POM)-PMEA and adefovir] was comparable in the three models. Compared with transport of the parent compound (adefovir), use of adefovir dipivoxil resulted in a significant increase in transport of total adefovir in the in vitro ( approximately 100-fold) and the in situ ( approximately 10-fold) models; in contrast, the ex vivo method failed to demonstrate a remarkable transport enhancement when using the ester prodrug. Similar to the results obtained in the Caco-2 model, the inclusion of the P-glycoprotein inhibitor verapamil resulted in transport enhancement during in situ perfusion of rat ileum with adefovir dipivoxil; however, no effect of verapamil could be observed in the ex vivo model. The results of this study confirm the utility of both the in vitro and in situ models to assess intestinal transport and metabolism of adefovir dipivoxil. The ex vivo model appeared to be less appropriate because of its inability to discriminate transport following administration of adefovir or adefovir dipivoxil and because of the absence of an effect of verapamil on transport when using adefovir dipivoxil.
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Affiliation(s)
- P Annaert
- Laboratory of Pharmacotechnology & Biopharmacy, KULeuven, Leuven, Belgium
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16
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Swaan PW, Koops BC, Moret EE, Tukker JJ. Mapping the binding site of the small intestinal peptide carrier (PepT1) using comparative molecular field analysis. Recept Channels 1999; 6:189-200. [PMID: 10100327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The present study was undertaken to examine the relationship between chemical structure (steric and electrostatic fields) and affinity for the small intestinal oligopeptide carrier (PepT1) using comparative molecular field analysis (CoMFA), a three-dimensional approach towards building quantitative structure-activity relationships. Various biological activity parameters (Kt, Jmax, Pc) and molecular descriptors (CoMFA fields, isobutylalcohol/water distribution coefficients) were examined. The resulting field map provides information on the geometry of the binding site cavity and the relative weights of various properties in different site pockets for each of the substrates considered. The results indicate that carrier permeability (Pc), calculated as the ratio of the half-maximal concentration (Kt) and the maximal carrier flux (Jmax), is sensitive to composition, size and hydrophobicity of the ligands. The best model obtained showed a high correlation between the carrier permeability (Pc) and the steric (76.3% contribution) and electrostatic (23.7% contribution) molecular fields with a cross-validated r2 (q2) of 0.754. The model fitted the experimental data with a correlation coefficient of 0.993 and a standard error of 0.041, while the regression line between experimental and calculated Pc had a slope of 0.994 with an intercept of 0.009. These results lead to a better understanding of the molecular requirements for optimal drug-carrier interactions with the intestinal peptide transporter and offers a useful visual aid for designing new potentially interesting structures with affinity for the oligopeptide transporter PepT1.
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Affiliation(s)
- P W Swaan
- Department of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, (UIPS), University of Utrecht, The Netherlands.
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17
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Schoenmakers RG, Stehouwer MC, Tukker JJ. Structure-transport relationship for the intestinal small-peptide carrier: is the carbonyl group of the peptide bond relevant for transport? Pharm Res 1999; 16:62-8. [PMID: 9950280 DOI: 10.1023/a:1018866611555] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The objective of this study was to determine the influence of the peptide bond with emphasis on the carbonyl group on the interaction with and transport by the intestinal small-peptide carrier. Therefore enalapril, a known substrate for the small-peptide carrier, has been modified to an analogue with a reduced peptide bond, enamipril. The transport characteristics of both compounds have been determined. METHODS The in vitro transport studies were performed using rat ileum in Ussing chambers. The transport of enalapril and enamipril were measured in a concentration range from 0.5-8 mM in both directions across the ileum. in the presence and absence of inhibitors. The interaction with the small-peptide carrier was studied by evaluating the ability of enalapril and its analogue enamipril to inhibit the transport rate of amoxycillin. RESULTS Enalapril shows, besides passive diffusion (P(m)3.06+/-0.14 . 10(-6)cm/s), saturable transport kinetics (Jmax = 16+/-5 nmol/h.cm2, Km = 1.86+/-0.64 mM) which can be inhibited with 10 mM cephalexin. The analogue with a reduced peptide bond does not show saturable transport from the mucosal to the serosal side, and cephalexin does not inhibit the flux of enamipril. However, the transport of enamipril from the serosal to mucosal side of the intestinal membrane is saturable and can be inhibited by 100 microM verapamil. Although enamipril is not a substrate for the small-peptide carrier in contrast to enalapril, both enalapril and enamipril are able to inhibit the active transport of amoxycillin with a K(i) of 0.41+/-0.24 mM and 0.24+/-0.12 mM respectively. CONCLUSIONS The reduction of the peptide bond of enalapril results in a compound, enamipril, which does not show polarized and saturable transport from the mucosal to the serosal side of the intestinal tissue. Also because the transport of enamipril cannot be inhibited by cephalexin, the analogue with the reduced peptide bond is no longer a substrate for the intestinal small-peptide carrier. Therefore, it can be concluded that the carbonyl group is an essential structural requirement for transport by the small-peptide carrier. In contrast, the interaction with the small-peptide carrier is still present, shown by the inhibition of the fluxes of amoxycillin. Reduction of the peptide bond of enalapril resulted in a new substrate for the P-glycoprotein efflux pump.
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Affiliation(s)
- R G Schoenmakers
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Faculty of Pharmacy, Universiteit Utrecht, The Netherlands
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18
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Kristl A, Tukker JJ. Negative correlation of n-octanol/water partition coefficient and transport of some guanine derivatives through rat jejunum in vitro. Pharm Res 1998; 15:499-501. [PMID: 9563085 DOI: 10.1023/a:1011901104421] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- A Kristl
- Faculty of Pharmacy, University of Ljubljana, Slovenia
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19
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Abstract
Computer-aided conformational analysis was used to characterize the pharmacophore for the intestinal peptide carrier. The active analog approach to pharmacophore building was applied as implemented in the SYBYL software package. Conformational analysis and MOPAC calculations were used to determine the lowest energy conformation of carrier substrates, as well as the conformations of compounds that displayed a common pharmacophoric geometry (i.e., inhibitors and inactive structural analogs). A pharmacophore map was calculated, and based on structural mutualities and functional topology, three substrate groups were suggested: compounds that bind to the transporter and are transferred across the membrane; compounds that show affinity for the peptide carrier (i.e., known to inhibit transport of substrates) but are not transferred across the membrane; and compounds that contain the pharmacophoric geometry but show no affinity for the carrier. Affinity for the peptide transporter can be diminished or abolished in either of three ways: esterification of the free carboxylic acid moiety; introduction of a second negative group; and intramolecular steric hindrance of the free carboxylic acid by either side chains with a positively charged nitrogen function or groups capable of hydrogen bond formation.
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Affiliation(s)
- P W Swaan
- Department of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, University of Utrecht, The Netherlands
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20
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Abstract
The distribution of penicillins into a tissue chamber implanted subcutaneously in ponies was studied. Ampicillin sodium (equivalent to 15 mg/kg ampicillin) was administered intravenously. Pivampicillin, a prodrug of ampicillin, was administered by nasogastric tube to fed ponies at a dose of 19.9 mg/kg (equivalent to 15 mg/kg ampicillin). Procaine penicillin G was administered intramuscularly at a dose of 12 mg/kg (equivalent to 12000 IU/kg). Six ponies were used for each medication. Antibiotic concentrations in plasma and tissue chamber fluid (TCF) were measured for 24 h after administration. Mean peak concentrations of ampicillin in TCF were 7.3 micrograms/mL, reached at 1.7 h, and 1.3 micrograms/mL, reached at 2.7 h, after administration of ampicillin sodium and pivampicillin respectively. The mean peak concentration of penicillin G of 0.3 microgram/mL was reached 12.3 h after administration of procaine penicillin G. Concentrations in TCF remained above the minimum inhibitory concentration of Streptococcus zooepidemicus for the proposed dosing intervals of 8, 12 and 24 h for ampicillin sodium, pivampicillin and procaine penicillin G respectively.
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Affiliation(s)
- J M Ensink
- Department of General and Large Animal Surgery, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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21
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Beyer WE, Palache AM, Sprenger MJ, Hendriksen E, Tukker JJ, Darioli R, van der Water GL, Masurel N, Osterhaus AD. Effects of repeated annual influenza vaccination on vaccine sero-response in young and elderly adults. Vaccine 1996; 14:1331-9. [PMID: 9004442 DOI: 10.1016/s0264-410x(96)00058-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three cohort studies in adults were performed during the period from 1986 to 1989. Eight hundred and eighty-four subjects were, one or more times, immunized with influenza vaccines, and pre- and post-vaccination antibody titres were determined by hemagglutination inhibition tests. One thousand and one hundred and nineteen vaccination events in 681 subjects could be analysed by a comparison, per trial and per influenza (sub)type, between groups with and without influenza vaccination in previous years. Effect size, odds ratio and protection rate difference, were used as effect measures. Subjects with previous vaccination showed higher pre-vaccination antibody than those without. The average change of the post-vaccination proportion of subjects with high antibody titre value to previous vaccination, was +9.4% (95% CI: +5.3 to 13.6%) for A-H3N2 vaccine components, -2.1% (-8.1 to 3.9%, not significant) for A-H1N1 and -10.6% (-16.5% to -4.8%) for B. In a linear regression model, pre-vaccination titres and the status of previous vaccination were identified as factors significantly influencing post-vaccination titres. These findings are discussed in the context of a short review of the literature. It is concluded that the status of previous vaccination should always be addressed as an independent factor in serological vaccination studies.
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Affiliation(s)
- W E Beyer
- WHO National Influenza Centre, Institute of Virology, Erasmus University Rotterdam, The Netherlands
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22
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Ensink JM, Vulto AG, van Miert AS, Tukker JJ, Winkel MB, Fluitman MA. Oral bioavailability and in vitro stability of pivampicillin, bacampicillin, talampicillin, and ampicillin in horses. Am J Vet Res 1996; 57:1021-4. [PMID: 8807014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To determine the oral bioavailabilities of 3 ampicillin esters (pivampicillin, bacampicillin, and talampicillin) and ampicillin sodium, and to determine in vitro stability of the ampicillin esters in ileal contents (pH 8.3 to 8.5). DESIGN A crossover design to administer the 4 drugs orally, and ampicillin i.v. to all horses in the study. ANIMALS 4 healthy adult horses. PROCEDURE The drugs were administered intragastrically to the horses at a dosage equimolar to 15 mg of ampicillin/kg of body weight. Also, ampicillin sodium was administered i.v. at the same dosage. Blood samples were taken up to 12 hours after drug administration, and ampicillin concentrations in plasma were determined. For the in vitro study, the ampicillin esters were incubated at 37 C in ileal contents obtained from ponies with cecal fistulas. After incubation, the remaining intact ester and the formed ampicillin were measured. RESULTS Absolute oral bioavailability was 31, 39, 23, and 2% for pivampicillin, bacampicillin, talampicillin, and ampicillin sodium, respectively. In the in vitro study, 90% decomposition of the ester took place in 30, 60, and 5 minutes, for pivampicillin, bacampicillin, and talampicillin, respectively. CONCLUSIONS Pivampicillin and bacampicillin are promising candidates for oral antibiotic treatment of horses. The rapid decomposition of ampicillin esters is caused by chemical hydrolysis at the high pH of equine ileal contents.
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Affiliation(s)
- J M Ensink
- Department of General and Large Animal Surgery, Utrecht University, The Netherlands
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23
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Swaan PW, Stehouwer MC, Tukker JJ. Molecular mechanism for the relative binding affinity to the intestinal peptide carrier. Comparison of three ACE-inhibitors: enalapril, enalaprilat, and lisinopril. Biochim Biophys Acta 1995; 1236:31-8. [PMID: 7794953 DOI: 10.1016/0005-2736(95)00030-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The affinity of three substrates for the intestinal peptide carrier is explained based on their three-dimensional (3D) structural data. The kinetic transport parameters of three ACE-inhibitors, enalapril, enalaprilat, and lisinopril, have been determined in an in vivo system using rat intestine. The observed kinetic transport parameters (+/- asymptotic standard error) of enalapril are: 0.81 (+/- 0.23) mM, 0.58 (+/- 0.37) mumol/h per cm2, and 0.56 (+/- 0.04) cm/h for the half-maximal transport concentration (KT), the maximal transport flux (Jmax) and the passive permeability constant (Pm). Enalaprilat was transported by passive diffusional with a Pm of 0.51 (+/- 0.04) cm/h. For lisinopril the kinetic transport parameters were 0.38 (+/- 0.19) mM, 0.12 (+/- 0.07) mumol/h per cm2, and 0.18 (+/- 0.02) cm/h for KT, Jmax, and Pm, respectively. The affinity of the ACE-inhibitors for the intestinal peptide carrier has been evaluated based on their ability to inhibit the transport rate of cephalexin. The inhibition constants (Ki) of enalapril, enalaprilat and lisinopril were 0.15, 0.28 and 0.39 mM, respectively. 3D structural analysis of lisinopril using molecular modelling techniques reveals that intramolecular hydrogen bond formation is responsible for decreased carrier affinity.
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Affiliation(s)
- P W Swaan
- Department of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences (UIPS), University of Utrecht, The Netherlands
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24
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Swaan PW, Tukker JJ. Carrier-mediated transport mechanism of foscarnet (trisodium phosphonoformate hexahydrate) in rat intestinal tissue. J Pharmacol Exp Ther 1995; 272:242-7. [PMID: 7815338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
New findings are presented on the specific transport mechanisms of foscarnet (trisodium phosphonoformate hexahydrate) in rat small intestinal tissue and proof for the partial participation of the Na(+)-phosphate co-transport system in foscarnet transport. The transport of the free acid form of foscarnet, phosphonoformic acid (PFA), was studied in rat small intestine by applying Ussing chambers. Transport studies in both mucosal (m)-to-serosal (s) and s-to-m directions revealed polarization of PFA transport. In m-to-s studies, nonlinear concentration-dependent transport was observed and described by the following transport parameters (estimate +/- asymptotic standard error): 0.84 +/- 0.13 mumol/h.cm2, 1.13 +/- 0.29 mM and 0.22 +/- 0.05 cm/h for the maximal transport rate (Jmax), the half-maximal transport concentration (Kt) and the passive membrane permeability constant (Pm), respectively. PFA transport (1.0 mM) was reduced to 72% and to 56% in the presence of the structural analogs phosphate and arsenate (10 mM), respectively. Bidirectional transport studies of PFA at 38 degrees C and 4 degrees C revealed a higher decrease in transport rate for the m-to-s studies than for the s-to-m studies. The combined results of the experiments described in this study demonstrate that PFA transport across rat small intestine is partly passive, using both the paracellular and transcellular pathways, and partly carrier-mediated, involving the phosphate co-transport system.
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Affiliation(s)
- P W Swaan
- Department of Pharmaceutics, Utrecht Institute of Pharmaceutical Sciences, Faculty of Pharmacy, University of Utrecht, The Netherlands
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25
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Lu HH, Thomas JD, Tukker JJ, Fleisher D. Intestinal water and solute absorption studies: comparison of in situ perfusion with chronic isolated loops in rats. Pharm Res 1992; 9:894-900. [PMID: 1438003 DOI: 10.1023/a:1015848815616] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effects of lumenal glucose on jejunal water transport and the influence of glucose-induced water absorption on solute uptake from single-pass perfusions are compared in anesthetized rats in situ and isolated chronic loops in unanesthetized rats in vivo. While the magnitudes of solute membrane permeabilities are consistently higher in the chronic loop system, the effects on water transport and its promotion of jejunal solute uptake are comparable between the two experimental systems. The effect of glucose-induced water absorption on the enhanced/baseline jejunal uptake ratio of the hydrophilic drug, acetaminophen, is greater than that for the lipophilic drug, phenytoin, in both experimental systems. The fact that chronic loop effective solute permeabilities were equivalent to solute membrane permeabilities in situ is consistent with greater lumenal fluid mixing in vivo. In addition, in situ body temperature affects the uptake of phenytoin but not acetaminophen, water, or glucose. This suggests that active and paracellular solute transport is not compromised in situ, while membrane partitioning and diffusion of lipophilic species are more sensitive to experimental conditions.
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Affiliation(s)
- H H Lu
- College of Pharmacy, University of Michigan, Ann Arbor 48109-1065
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26
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van Bommel EM, Raghoebar M, Tukker JJ. Kinetics of acetaminophen after single- and multiple-dose oral administration as a gradient matrix system to healthy male subjects. Biopharm Drug Dispos 1991; 12:355-66. [PMID: 1878532 DOI: 10.1002/bdd.2510120505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The in vivo characteristics of two formulations of a recently developed controlled-release system, the Gradient Matrix System (GMS-1 and GMS-2), with acetaminophen as a model drug compound have been determined in healthy volunteers both after separate single- and multiple-dose administration. Values for the mean residence time (MRT) were increased from 5.2 h for an oral solution to 10.2 and 13.3 h for two GMS formulations after single dosing. Peak plasma concentrations were lower for the two GMS formulations after single dosing compared to the oral solution. The bioavailability, relative to the oral solution, was 91 per cent and 84 per cent for the two GMS formulations tested. After multiple dosing of one of the GMS formulations over 5 days, no change in AUC compared to the single dose AUC occurred. Steady state was reached within 2-3 days of twice daily dosing of the GMS formulation. The peak-trough-fluctuation (per cent PTF) was 44 per cent. No signs of dose dumping were observed in fasted subjects. A plateau-like plasma drug concentration profile at steady state was maintained with the GMS formulation.
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Affiliation(s)
- E M van Bommel
- Pharmaceutical Development Department, Duphar BV, Weesp, The Netherlands
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27
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van Bommel EM, Raghoebar M, Tukker JJ. Comparison of in vitro and in vivo release characteristics of acetaminophen from gradient matrix systems. Biopharm Drug Dispos 1991; 12:367-73. [PMID: 1878533 DOI: 10.1002/bdd.2510120506] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An effort was made to correlate the in vivo and in vitro release data of acetaminophen from two formulations of a recently developed controlled-release system, the Gradient Matrix System (GMS-1 and GMS-2). The in vivo release curves, obtained by deconvolution of the plasma concentration time plots, showed a small inter-subject variability. GMS-1 with fastest in vitro release also showed fastest in vivo release. A good relationship was only found after time-scaling of the release data.
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Affiliation(s)
- E M van Bommel
- Pharmaceutical Development Department, Duphar BV, Weesp, The Netherlands
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28
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Poelma FG, Breäs R, Tukker JJ, Crommelin DJ. Intestinal absorption of drugs. The influence of mixed micelles on on the disappearance kinetics of drugs from the small intestine of the rat. J Pharm Pharmacol 1991; 43:317-24. [PMID: 1680173 DOI: 10.1111/j.2042-7158.1991.tb06697.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The solubilization of the hydrophilic drugs paracetamol and theophylline, and the lipophilic drugs dantrolene, griseofulvin and ketoconazole has been determined in mixed micellar aqueous dispersions composed of 10 mM taurocholate + 5 mM oleic acid. The solubilization of dantrolene and paracetamol has also been determined in aqueous (mixed) micellar dispersions of 1 g L-1 lysophosphatidyl-choline (LPC), or taurocholate/LPC. The influence of these (mixed) micelles on the absorption of the model drugs from solution was studied in the rat chronically isolated internal loop. Absorption kinetics of the drugs were evaluated on the basis of the disappearance rate of the drug dissolved in the perfusion medium in this loop. Absorption experiments with taurocholate/oleic acid in the perfusate resulted in a reduction of the disappearance rate for the lipophilic drugs and the hydrophilic drug theophylline. This could partly be ascribed to the decreased fraction of drug free in solution as a result of its micellar solubilization for dantrolene, griseofulvin and ketoconazole, but the decrease in the disappearance rate of theophylline was unexpected. Taurocholate/oleic acid, LPC and taurocholate/LPC micelles had no effect on the disappearance of paracetamol. The disappearance rate of dantrolene in the presence of LPC alone was not altered, in spite of the decreased fraction of the drug free in solution owing to its micellar solubilization. In contrast, taurocholate/LPC micelles caused a reduction in the rate of disappearance of dantrolene, as expected according to the phase-separation model. In-vitro, taurocholate and taurocholate/LPC reduced the molecular cohesion of porcine intestinal mucus, whereas LPC alone did not exhibit an effect on the gel structure of mucus.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F G Poelma
- Department of Pharmaceutics, Faculty of Pharmacy, University of Utrecht, The Netherlands
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29
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Abstract
In vitro dissolution profiles of three controlled-release mesalazine formulations were determined at pH 1.0, 6.0 and 7.5. A closed-column type dissolution apparatus was used. A reproducible gradual dissolution profile was seen for Pentasa at all pH values. Dissolution starts immediately and is complete after 20 h. Dissolution profiles at pH 1 and pH 7.5 are much alike and dissolution is faster than at pH 6. The behaviour of Asacol at different pH values corresponds with the expectations: no release at pH 6 and pH 1, fast release at pH 7.5. Dissolution starts after 1 h and is complete after 3 h. Mesalazine release from Salofalk tablets at pH 7.5 and pH 6.0 starts after 2 and 3 h, respectively, and is complete after 5 and 10 h. However, after a long lag-time (10 h) mesalazine is also released from Salofalk tablets at pH 1 and dissolution is complete after 23 h.
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Affiliation(s)
- L M Stolk
- Pharmacy Department, Academic Medical Centre, Amsterdam, The Netherlands
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30
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Poelma FG, Breäs R, Tukker JJ. Intestinal absorption of drugs. III. The influence of taurocholate on the disappearance kinetics of hydrophilic and lipophilic drugs from the small intestine of the rat. Pharm Res 1990; 7:392-7. [PMID: 2362914 DOI: 10.1023/a:1015827624296] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The influence of sodium taurocholate (TC) on the intestinal absorption of drugs was studied in vivo in a chronically isolated internal loop in the rat. The hydrophilic drugs paracetamol (PA) and theophylline (TP) and the lipophilic drugs griseofulvin (GF) and ketoconazole (KE) were used as model drugs. The drug concentrations were kept below the saturation concentration. Absorption kinetics of the drugs were evaluated on the basis of disappearance rates of the drug from luminal solutions in the intestinal loop. Concentrations of TC above the critical micelle concentration (CMC) did not affect the absorption rate of the hydrophilic drugs PA and TP; the barrier function of the intestinal wall for PA and TP was not altered in the presence of taurocholate. The addition of concentrations of TC above the CMC in the perfusion solution resulted in a reduction of the absorption rate of GF and KE. The reduction in the absorption kinetics of GF in the presence of TC correlated well with the reduction of the drug-free fraction in solution due to micellar solubilization. For KE this relation was less clear. It was not possible to determine, on the basis of the phase-separation model, to what extent the fraction of the drug incorporated in TC micelles contributes to the overall diffusion of GF and KE across the preepithelial diffusion barrier. It was concluded that TC exhibits only a minor, if not negligible, effect on the barrier function of the aqueous diffusion barrier adjacent to the intestinal wall.
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Affiliation(s)
- F G Poelma
- Department of Pharmaceutics, Faculty of Pharmacy, University of Utrecht, The Netherlands
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31
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Poelma FG, Tukker JJ, Crommelin DJ. Intestinal absorption of drugs. I: The influence of taurocholate on the absorption of dantrolene in the small intestine of the rat. J Pharm Sci 1989; 78:285-9. [PMID: 2724091 DOI: 10.1002/jps.2600780405] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The influence of sodium taurocholate (1) on the intestinal absorption of the lipophilic drug dantrolene (2) was studied in vivo in a chronically isolated internal loop in the rat. Concentrations of 2 were kept below the saturation concentration in saline. Absorption kinetics of 2 were evaluated on the basis of steady-state blood levels, which develop during single-pass perfusions, and on the basis of the rate of disappearance of the drug from the perfusate during recirculating perfusions. Compound 1 at a concentration of 10 mM in the perfusate induced a twofold reduction of the absorption rate compared with the same concentration of 2 in saline. Pretreatment of the absorptive surface with a 10 mM solution of 1 had no detectable effect on the absorption rate of 2 in saline. After perfusions with 10 mM solutions of 1, the perfusate concentration of proteins, phosphorus, and hexoses in the effluent was increased. The reduction of the absorption rate can be ascribed mainly to a reduction of the thermodynamically active concentration of 2 as calculated from the phase-separation model. In addition, 10 mM 1 seems to temporarily increase the barrier function of the mucous layer.
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Affiliation(s)
- F G Poelma
- Department of Pharmaceutics, Faculty of Pharmacy, University of Utrecht, The Netherlands
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32
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Abstract
A model is described to study absorption kinetics of drugs in the unanesthetized rat. The surgical technique consists of a long-term isolation of an intestinal segment inside the animal. This isolated loop is used in perfusion experiments. In this model the effects of anesthesia and surgical trauma on absorption kinetics are absent. In addition, this model allows for cross-over experimental schemes. Absorption kinetics are evaluated on the basis of steady-state blood levels (Css) of the perfused drug, since the animal can be used in experiments over a long time period. Steady-state blood levels can be used as a measure of the absorption if the compound under investigation shows linear elimination kinetics. Dantrolene sodium was used as a model compound to evaluate this technique. The elimination of dantrolene sodium followed linear kinetics after different intravenous doses in the same rat. The half-life of elimination (t1/2 beta) of dantrolene sodium was approximately 45 min. Perfusions of two different concentrations of dantrolene sodium in the same rat showed that an increase of the perfusate concentration results in a proportional increase in the Css. A prerequisite for performing cross-over experiments is that the absorption characteristics of the isolated segment are constant during the experimental period. This model showed a constant absorption of dantrolene sodium on consecutive days, over a two-week period, in the same rat.
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33
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Abstract
The bioavailability of tamoxifen from 40 mg suppositories was tested in six male volunteers and compared with that of tamoxifen (Nolvadex) tablets. Plasma concentrations of tamoxifen and its major metabolites, 4-hydroxytamoxifen and N-desmethyltamoxifen, were measured by extraction from plasma obtained at different times after administration, separated by HPLC, converted on-line to fluorescent phenanthrene derivatives and quantified with a fluorescence detector. The mean relative bioavailability from the suppositories was 28%; the addition of a surfactive agent diminished the bioavailability to 13%. Simulation of repeated administration of 40 mg suppositories suggests a mean steady state plasma concentration for tamoxifen of approximately 70 ng ml-1, i.e. 30% of the steady state value after simulated oral administration. Rectal administration of tamoxifen leads to a lower bioavailability than that by oral administration and therefore cannot be recommended when used in equivalent doses.
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Tukker JJ, Blankenstein MA, Nortier JW. Decreased bioavailability of tamoxifen after rectal administration. Eur J Cancer Clin Oncol 1986; 22:1083-4. [PMID: 3780815 DOI: 10.1016/0277-5379(86)90010-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Tukker JJ, Sitsen JM, Gusdorf CF. Bioavailability of paracetamol after oral administration to healthy volunteers. Influence of caffeine on rate and extent of absorption. Pharm Weekbl Sci 1986; 8:239-43. [PMID: 3763369 DOI: 10.1007/bf01957785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The absorption rate and the bioavailability of two commercially available paracetamol tablets were investigated in a panel of seven volunteers; one of these tablets contained a combination of 50 mg caffeine and paracetamol. Considering the urinary excretion data, it is concluded that the tablets release their contents completely; the absolute bioavailability, however, calculated from plasma concentrations, is lower than 100%, indicating a first-pass effect. A marked interindividual variation in first-pass effect was noticed. No general influence of caffeine on the extent of absorption of paracetamol could be established; there is, however, a slightly positive influence of caffeine on the absorption rate of paracetamol in six out of seven volunteers. It was concluded that this positive influence on absorption rate is not responsible for the established enhancement of paracetamol analgesia by caffeine.
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Schurgers N, Bijdendijk J, Tukker JJ, Crommelin DJ. Comparison of four experimental techniques for studying drug absorption kinetics in the anesthetized rat in situ. J Pharm Sci 1986; 75:117-9. [PMID: 3958918 DOI: 10.1002/jps.2600750203] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Theophylline absorption kinetics were determined using in situ perfusion techniques. The objectives of this study were to obtain information on the effective permeability constant (ke) of theophylline and its variance during the course of an experiment, and to study the dependence of ke on the experimental technique used. Four in situ intestinal perfusion techniques were compared in the rat: single-pass perfusion, recirculating perfusion, oscillating perfusion, and the closed loop method. The absorption of theophylline appeared to be strongly dependent on the hydrodynamics in the lumen. Constant values and similar coefficients of variation for ke values were obtained for the single-pass perfusion, the recirculating perfusion, and the oscillating perfusion methods. The closed-loop method suffered both from a dropping value of ke with time and a relatively large coefficient of variation.
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Tukker JJ, De Blaey CJ. Prolonged storage of aminophylline suppositories. The impact on physical parameters and bioavailability. Pharm Weekbl Sci 1984; 6:96-8. [PMID: 6728641 DOI: 10.1007/bf01953962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Prolonged storage of aminophylline/cocoa butter suppositories at 30 degrees resulted in a marked decrease in bioavailability, after administration to a panel of human volunteers. Not more than 20% of the drug content was absorbed during the first 8 hours and the maximum plasma level was obtained 5-7 hours after administration. It was concluded that storage conditions should be considered well and storage instructions should be given to the patient.
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Schuurkes JA, Tukker JJ. The interdigestive colonic motor complex of the dog. Arch Int Pharmacodyn Ther 1980; 247:329-34. [PMID: 7447571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Interdigestive colonic motor patterns of conscious dogs chronically implanted with strain gauge force transducers showed regularly recurring motor complexes. These motor complexes consisted of a sequence of 8-12 tonic contractions (frequency: 1.3/min), on which phasic contractions (frequency: 5-6/min) were superimposed. Complex duration was about 7 min, cycle duration about 32 min. These interdigestive motor complexes of the canine colon were not related to the small intestinal motor complexes and must therefore be considered as a unique and organ-specific motor pattern.
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