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Kinoshita N, Paul M, Kashiv Y, Collon P, Deibel CM, DiGiovine B, Greene JP, Jiang CL, Marley ST, Pardo RC, Rehm KE, Robertson D, Scott R, Schmitt C, Tang XD, Vondrasek R, Yokoyama A. Retraction. Science 2023; 379:1307. [PMID: 36996231 DOI: 10.1126/science.adh7739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Affiliation(s)
- N Kinoshita
- Shimizu Corporation Institute of Technology, Tokyo, Japan
| | - M Paul
- Hebrew University of Jerusalem, Jerusalem, Israel
| | - Y Kashiv
- University of Notre Dame, Notre Dame, IN, USA
| | - P Collon
- University of Notre Dame, Notre Dame, IN, USA
| | - C M Deibel
- Louisiana State University, Baton Rouge, LA, USA
| | - B DiGiovine
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | - J P Greene
- Argonne National Laboratory, Argonne, IL, USA
| | - C L Jiang
- Argonne National Laboratory, Argonne, IL, USA
| | - S T Marley
- Louisiana State University, Baton Rouge, LA, USA
| | - R C Pardo
- Argonne National Laboratory, Argonne, IL, USA
| | - K E Rehm
- Argonne National Laboratory, Argonne, IL, USA
| | - D Robertson
- University of Notre Dame, Notre Dame, IN, USA
| | - R Scott
- Argonne National Laboratory, Argonne, IL, USA
| | - C Schmitt
- University of Notre Dame, Notre Dame, IN, USA
| | - X D Tang
- Institute of Modern Physics, Lanzhou, China
| | - R Vondrasek
- Argonne National Laboratory, Argonne, IL, USA
| | - A Yokoyama
- Kanazawa University, Kakumamachi, Kanazawa, Ishikawa, Japan
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Tessler M, Paul M, Halfon S, Meyer BS, Pardo R, Purtschert R, Rehm KE, Scott R, Weigand M, Weissman L, Almaraz-Calderon S, Avila ML, Baggenstos D, Collon P, Hazenshprung N, Kashiv Y, Kijel D, Kreisel A, Reifarth R, Santiago-Gonzalez D, Shor A, Silverman I, Talwar R, Veltum D, Vondrasek R. Stellar ^{36,38}Ar(n,γ)^{37,39}Ar Reactions and Their Effect on Light Neutron-Rich Nuclide Synthesis. Phys Rev Lett 2018; 121:112701. [PMID: 30265109 DOI: 10.1103/physrevlett.121.112701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 07/24/2018] [Indexed: 06/08/2023]
Abstract
The ^{36}Ar(n,γ)^{37}Ar (t_{1/2}=35 d) and ^{38}Ar(n,γ)^{39}Ar (269 yr) reactions were studied for the first time with a quasi-Maxwellian (kT∼47 keV) neutron flux for Maxwellian average cross section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the ^{37}Ar/^{36}Ar and ^{39}Ar/^{38}Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The ^{37}Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of ^{36}Ar and ^{38}Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron-capture cross sections of ^{36,38}Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak s process. The new production cross sections have implications also for the use of ^{37}Ar and ^{39}Ar as environmental tracers in the atmosphere and hydrosphere.
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Affiliation(s)
- M Tessler
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - M Paul
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | | | - B S Meyer
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USA
| | - R Pardo
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R Purtschert
- Physics Institute, University of Bern, 3012 Bern, Switzerland
| | - K E Rehm
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R Scott
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M Weigand
- Goethe University Frankfurt, Frankfurt 60438, Germany
| | | | | | - M L Avila
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Baggenstos
- Physics Institute, University of Bern, 3012 Bern, Switzerland
| | - P Collon
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | | | - Y Kashiv
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - D Kijel
- Soreq NRC, Yavne 81800, Israel
| | | | - R Reifarth
- Goethe University Frankfurt, Frankfurt 60438, Germany
| | - D Santiago-Gonzalez
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - A Shor
- Soreq NRC, Yavne 81800, Israel
| | | | - R Talwar
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Veltum
- Goethe University Frankfurt, Frankfurt 60438, Germany
| | - R Vondrasek
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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Scott R, Palchan T, Pardo R, Vondrasek R, Kondev F, Nusair O, Peters C, Paul M, Bauder W, Collon P. Progress of laser ablation for accelerator mass spectroscopy at ATLAS utilizing an ECRIS. Rev Sci Instrum 2014; 85:02A901. [PMID: 24593480 DOI: 10.1063/1.4824756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Beams of ions from the laser ablation method of solid materials into an electron cyclotron resonance ion source (ECRIS) plasma have been used for the first time in experiments at ATLAS. Initial accelerator mass spectroscopy experiments using laser ablation for actinides and samarium have been performed. Initial results of coupling the laser system to the ECR source have guided us in making a number of changes to the original design. The point of laser impact has been moved off axis from the center of the ECR injection side. Motor control of the laser positioning mirror has been replaced with a faster and more reliable piezo-electric system, and different raster scan patterns have been tested. The use of the laser system in conjunction with a multi-sample changer has been implemented. Two major problems that are being confronted at this time are beam stability and total beam intensity. The status of the development will be presented and ideas for further improvements will be discussed.
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Affiliation(s)
- R Scott
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - T Palchan
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - R Pardo
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - R Vondrasek
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - F Kondev
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - O Nusair
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - C Peters
- Physics Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - M Paul
- Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel
| | - W Bauder
- Nuclear Structure Laboratory, University of Notre Dame, Indiana 46556, USA
| | - P Collon
- Nuclear Structure Laboratory, University of Notre Dame, Indiana 46556, USA
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4
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Kinoshita N, Paul M, Kashiv Y, Collon P, Deibel CM, DiGiovine B, Greene JP, Henderson DJ, Jiang CL, Marley ST, Nakanishi T, Pardo RC, Rehm KE, Robertson D, Scott R, Schmitt C, Tang XD, Vondrasek R, Yokoyama A. A Shorter
146
Sm Half-Life Measured and Implications for
146
Sm-
142
Nd Chronology in the Solar System. Science 2012; 335:1614-7. [PMID: 22461609 DOI: 10.1126/science.1215510] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The extinct p-process nuclide (146)Sm serves as an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter (142)Nd. Based on analyses of (146)Sm/(147)Sm α-activity and atom ratios, we determined the half-life of (146)Sm to be 68 ± 7 (1σ) million years, which is shorter than the currently used value of 103 ± 5 million years. This half-life value implies a higher initial (146)Sm abundance in the early solar system, ((146)Sm/(144)Sm)(0) = 0.0094 ± 0.0005 (2σ), than previously estimated. Terrestrial, lunar, and martian planetary silicate mantle differentiation events dated with (146)Sm-(142)Nd converge to a shorter time span and in general to earlier times, due to the combined effect of the new (146)Sm half-life and ((146)Sm/(144)Sm)(0) values.
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Affiliation(s)
- N. Kinoshita
- Research Facility Center for Science and Technology, University of Tsukuba, Japan
| | - M. Paul
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel 91904
| | - Y. Kashiv
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556–5670, USA
| | - P. Collon
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556–5670, USA
| | - C. M. Deibel
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 46624, USA
| | - B. DiGiovine
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - J. P. Greene
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - D. J. Henderson
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - C. L. Jiang
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - S. T. Marley
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - T. Nakanishi
- Faculty of Chemistry, Institute of Science and Engineering, Kanazawa University, Japan
| | - R. C. Pardo
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - K. E. Rehm
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - D. Robertson
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556–5670, USA
| | - R. Scott
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - C. Schmitt
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556–5670, USA
| | - X. D. Tang
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556–5670, USA
| | - R. Vondrasek
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - A. Yokoyama
- Faculty of Chemistry, Institute of Science and Engineering, Kanazawa University, Japan
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5
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Kinoshita N, Hashimoto T, Nakanishi T, Yokoyama A, Amakawa H, Mitsugashira T, Ohtsuki T, Takahashi N, Ahmad I, Greene JP, Henderson DJ, Jiang CL, Notani M, Pardo RC, Patel N, Rehm KE, Scott R, Vondrasek R, Jisonna L, Collon P, Robertson D, Schmitt C, Tang XD, Kashiv Y, Paul M. Technological Development for Half-life Measurement of 146Sm Nuclide. ACTA ACUST UNITED AC 2007. [DOI: 10.14494/jnrs2000.8.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nassar H, Paul M, Ahmad I, Berkovits D, Bettan M, Collon P, Dababneh S, Ghelberg S, Greene JP, Heger A, Heil M, Henderson DJ, Jiang CL, Käppeler F, Koivisto H, O'Brien S, Pardo RC, Patronis N, Pennington T, Plag R, Rehm KE, Reifarth R, Scott R, Sinha S, Tang X, Vondrasek R. Stellar (n,gamma) cross section of 62Ni. Phys Rev Lett 2005; 94:092504. [PMID: 15783960 DOI: 10.1103/physrevlett.94.092504] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 12/15/2004] [Indexed: 05/24/2023]
Abstract
The 62Ni(n,gamma)63Ni(t(1/2)=100+/-2 yr) reaction plays an important role in the control of the flow path of the slow neutron-capture (s) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT=25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+/-2.8 mb, fairly consistent with a recent calculation, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62<A<90 produced by the weak s process in massive stars.
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Affiliation(s)
- H Nassar
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel, 91904
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7
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Rehm KE, Jiang CL, Ahmad I, Caggiano J, Collon P, Greene JP, Henderson D, Heinz A, Janssens RVF, Pardo RC, Pennington T, Schiffer JP, Siemssen RH, Wuosmaa AH, Paul M, Mohr P. Large angle elastic alpha scattering on a N=Z nucleus above A=40. Phys Rev Lett 2002; 89:132501. [PMID: 12225019 DOI: 10.1103/physrevlett.89.132501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2002] [Indexed: 05/23/2023]
Abstract
Scattering of alpha particles from 44Ti, the lightest unstable alpha-particle nucleus above A=40, has been measured at backward angles. The "anomalous" order-of-magnitude enhancement that is characteristic of 40Ca and other light alpha-particle nuclei is not observed. Instead, the backward yield is similar to that observed for other nuclei heavier than 40Ca, and is well described with average optical model parameters.
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Affiliation(s)
- K E Rehm
- Argonne National Laboratory, Argonne, Illinois 60439, USA
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8
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Jiang CL, Esbensen H, Rehm KE, Back BB, Janssens RVF, Caggiano JA, Collon P, Greene J, Heinz AM, Henderson DJ, Nishinaka I, Pennington TO, Seweryniak D. Unexpected behavior of heavy-ion fusion cross sections at extreme sub-barrier energies. Phys Rev Lett 2002; 89:052701. [PMID: 12144438 DOI: 10.1103/physrevlett.89.052701] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2002] [Indexed: 05/23/2023]
Abstract
The excitation function for fusion evaporation in the (60)Ni+ (89)Y system was measured over a range in cross section covering 6 orders of magnitude. The cross section exhibits an abrupt decrease at extreme sub-barrier energies. This behavior, which is also present in a few other systems found in the literature, cannot be reproduced with present models, including those based on a coupled-channels approach. Possible causes are discussed, including a dependence on the intrinsic structure of the participants.
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Affiliation(s)
- C L Jiang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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9
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Collon P, Cole D, Davids B, Fauerbachs M, Harkewicz R, Kutschera W, Morrissey DJ, Pardo RC, Paul M, Sherrill BM, Steiner M. Measurement of the Long-lived Radionuclide 81Kr in Pre-nuclear and Present-day Atmospheric Krypton. ACTA ACUST UNITED AC 1999. [DOI: 10.1524/ract.1999.85.12.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- P. Collon
- Vienna Environmental Research Accelerator, Institut für Radiumforschung und Kernphysik, Universität Wien, Währingerstr. 17, A-1090 Wien, Austria
| | - D. Cole
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - B. Davids
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - M. Fauerbachs
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - R. Harkewicz
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | | | - D. J. Morrissey
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - R. C. Pardo
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - M. Paul
- Racah Institute for Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - B. M. Sherrill
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - M. Steiner
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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10
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Carpéné C, Collon P, Remaury A, Cordi A, Hudson A, Nutt D, Lafontan M. Inhibition of amine oxidase activity by derivatives that recognize imidazoline I2 sites. J Pharmacol Exp Ther 1995; 272:681-8. [PMID: 7853182] [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
Nonadrenergic imidazoline binding sites (imidazoline I2 sites) have been described to be colocated with monoamine oxidase (MAO) in the mitochondrial fraction of various cell types. In the present work, the authors considered whether this colocation could be associated with a functional interplay. In rat liver membranes, [3H]-idazoxan binding to I2 receptors was competed for by naphazoline and idazoxan, which also shared a high affinity for alpha-2 adrenoceptors (alpha-2 ARs). The chemicals 2-n-heptylimidazoline (S 15430), 1-methyl-5-n-heptylimidazole (S 15674), 2-benzofuran-2-yl-imidazoline (RX 801077) and 2-(1,3-benzodioxanyl)-2-imidazoline (RX 821029) exhibited higher affinity for I2 receptors than for alpha-2 ARs. The most selective agent was S 15430 with a 150-fold higher affinity for liver I2 receptors than for adipocyte alpha-2 ARs. Moreover, [3H]-idazoxan binding was also competed for by several MAO inhibitors (MAOI) that are not imidazoline or guanidinium derivatives such as tranylcypromine, harmaline, clorgiline and pargyline. Rat liver MAO activity was not only inhibited by MAOIs but also by some imidazoline derivatives: cirazoline, naphazoline, S 15674, RX 801077 and RX 821029. Idazoxan had no effect on MAO activity; it neither inhibited MAO nor prevented the inhibition induced by other imidazolines or MAOIs. This suggested that the ligand recognition site of I2 receptors was distinct from the MAOI target site. Furthermore, some imidazolines inhibited the activity of bovine plasma amine oxidase, an enzyme that does not possess the same cofactor as MAO and is insensitive to harmaline or pargyline.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Carpéné
- Institut National de la Santé et de la Recherche Médicale (INSERM U 317), Institut Louis Bugnard, Université Paul Sabatier, Toulouse, France
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11
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Carpéné C, Castan I, Collon P, Galitzky J, Moratinos J, Lafontan M. Adrenergic lipolysis in guinea pig is not a beta 3-adrenergic response: comparison with human adipocytes. Am J Physiol 1994; 266:R905-13. [PMID: 7909205 DOI: 10.1152/ajpregu.1994.266.3.r905] [Citation(s) in RCA: 9] [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] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
beta 3-Adrenoceptor agonists are potent lipolytic activators in rats, but they are only weak stimulators in human adipocytes, indicating interspecies differences in the adrenergic regulation of lipid mobilization. Like human but not rat adipocytes, guinea pig fat cells were poorly responsive to the beta 3-agonists BRL-37344, CGP-12177, SR-58611, and ICI-215001, acid metabolite of ICI-D7114. In guinea pigs, the beta 1-agonist dobutamine was more lipolytic than the beta 2-agonist procaterol. Anatomic location of fat deposits was without major influence on the beta-adrenergic responsiveness. Weak responses to beta 3-agonists were found whatever the sex or the age (from 2 days to 16 mo) of the animals. Even in the interscapular brown adipose tissue, which is well known in rats for its beta 3-adrenergic responsiveness, a blunted response to BRL-37344 was observed. The alpha 2-adrenergic antilipolytic effect and receptor number were smaller in guinea pig than in human adipocytes, but the beta-adrenergic receptor number was similar in the two species. Thus guinea pig adipocytes resemble human fat cells when their weak beta 3-adrenergic responsiveness is considered.
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Affiliation(s)
- C Carpéné
- Institut National de la Santé et de la Recherche Médicale, Université Paul Sabatier, Toulouse, France
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12
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Carpéné C, Galitzky J, Collon P, Esclapez F, Dauzats M, Lafontan M. Desensitization of beta-1 and beta-2, but not beta-3, adrenoceptor-mediated lipolytic responses of adipocytes after long-term norepinephrine infusion. J Pharmacol Exp Ther 1993; 265:237-47. [PMID: 8097243] [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: 01/28/2023] Open
Abstract
The beta-3 adrenoceptor protein lacks most of the potential phosphorylation sites for beta adrenoceptor kinase and protein kinase A. In addition, it exhibits a lower affinity toward norepinephrine than beta-1 or beta-2 adrenoceptors. It is thus expected that beta-3 adrenoceptors could be less implicated in desensitization processes than the beta-1 or beta-2 adrenoceptors. An attempt to demonstrate the physiological relevance of this prediction was performed by using fat cells having a beta-3 adrenergic responsiveness or not (hamster and guinea pig). The influence of prolonged in vivo exposure to norepinephrine on the beta adrenoceptor-mediated lipolytic responses was investigated in both species. In control guinea pigs, isoproterenol, norepinephrine and epinephrine were fully lipolytic, whereas BRL 37344 [(R',R')-4-2[2-((2[(3-chlorophenyl)-2-hydroxyethyl]amino] propyl)phenyl]phenoxyacetic acid], CGP 12177](+-)-4-(3-tertiarybutylamino-2-hydroxypropoxy)- benzimidazole-2-on hydrochloride] and other beta-3 agonists were inefficient, whereas hamster adipocytes exhibited maximal response to the beta-3 agonists. Blockade of the lipolytic effect of isoproterenol in the guinea pig gave a rank order of beta antagonists [CGP 20712A (1-[2-(3-carbamoyl-4-hydroxyphenoxy)ethylamino]-3-4-(1-methyl-4-tr i-fluoro-methyl-1H-imidazol-2-yl)phenoxy-2-propanol methanesulfonate] > bupranolol > or = propranolol >> ICI 118551 [erythrodl-1-(7- methylindan-4-yloxy)-3-isopropylaminobutan-2-ol)] in agreement with that of a beta-1 effect. In contrast, the selective beta-1 antagonist CGP 20712A did not counteract the effect of BRL 37344 in hamsters and bupranolol was the best beta antagonist tested; a result arguing for the predominance of a beta-3 component in the adrenergic activation of lipolysis, as in rat fat cells. In treated guinea pigs (6-day treatment with osmotic minipumps delivering norepinephrine at the rate of 5 micrograms/min/kg), the adrenocorticotropic hormone dose-response curve was identical to that of controls, but the curves for isoproterenol, norepinephrine and epinephrine were flattened and shifted to the right. A down-regulation of beta-1 and beta-2 adrenoceptors was evidenced by a reduction in [3H]CGP 12177 high-affinity binding sites. In treated hamsters, compared to the controls, there was no change in the lipolytic response to the beta adrenergic agonists. Other protocols of chronic exposure to norepinephrine (e.g., daily injections) at different doses were also unable to reduce the beta-lipolytic effect in the hamster fat cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- C Carpéné
- Institut National de la Santé et de la Recherche Médicale (I.N.S.E.R.M. U 317), Institut Louis Bugnard, Faculté de Médecine, C.H.U. Rangueil, Toulouse, France
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