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Pereira PA, Tavares M, Laires M, Mota B, Madeira MD, Paula-Barbosa MM, Cardoso A. Effects of Aging and Nerve Growth Factor on Neuropeptide Expression and Cholinergic Innervation of the Rat Basolateral Amygdala. BIOLOGY 2024; 13:155. [PMID: 38534426 DOI: 10.3390/biology13030155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/28/2024]
Abstract
The basolateral amygdala (BLA) contains interneurons that express neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), both of which are involved in the regulation of functions and behaviors that undergo deterioration with aging. There is considerable evidence that, in some brain areas, the expression of NPY and VIP might be modulated by acetylcholine. Importantly, the BLA is one of the brain regions that has one of the densest cholinergic innervations, which arise mainly from the basal forebrain cholinergic neurons. These cholinergic neurons depend on nerve growth factor (NGF) for their survival, connectivity, and function. Thus, in this study, we sought to determine if aging alters the densities of NPY- and VIP-positive neurons and cholinergic varicosities in the BLA and, in the affirmative, if those changes might rely on insufficient trophic support provided by NGF. The number of NPY-positive neurons was significantly reduced in aged rats, whereas the number of VIP-immunoreactive neurons was unaltered. The decreased NPY expression was fully reversed by the infusion of NGF in the lateral ventricle. The density of cholinergic varicosities was similar in adult and old rats. On the other hand, the density of cholinergic varicosities is significantly higher in old rats treated with NGF than in adult and old rats. Our results indicate a dissimilar resistance of different populations of BLA interneurons to aging. Furthermore, the present data also show that the BLA cholinergic innervation is particularly resistant to aging effects. Finally, our results also show that the reduced NPY expression in the BLA of aged rats can be related to changes in the NGF neurotrophic support.
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Affiliation(s)
- Pedro A Pereira
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Marta Tavares
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Miguel Laires
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Bárbara Mota
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Maria Dulce Madeira
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Manuel M Paula-Barbosa
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Armando Cardoso
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
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Karoglu-Eravsar ET, Tuz-Sasik MU, Karaduman A, Keskus AG, Arslan-Ergul A, Konu O, Kafaligonul H, Adams MM. Long-Term Acetylcholinesterase Depletion Alters the Levels of Key Synaptic Proteins while Maintaining Neuronal Markers in the Aging Zebrafish (Danio rerio) Brain. Gerontology 2023; 69:1424-1436. [PMID: 37793352 PMCID: PMC10711754 DOI: 10.1159/000534343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023] Open
Abstract
INTRODUCTION Interventions targeting cholinergic neurotransmission like acetylcholinesterase (AChE) inhibition distinguish potential mechanisms to delay age-related impairments and attenuate deficits related to neurodegenerative diseases. However, the chronic effects of these interventions are not well described. METHODS In the current study, global levels of cholinergic, cellular, synaptic, and inflammation-mediating proteins were assessed within the context of aging and chronic reduction of AChE activity. Long-term depletion of AChE activity was induced by using a mutant zebrafish line, and they were compared with the wildtype group at young and old ages. RESULTS Results demonstrated that AChE activity was lower in both young and old mutants, and this decrease coincided with a reduction in ACh content. Additionally, an overall age-related reduction in AChE activity and the AChE/ACh ratio was observed, and this decline was more prominent in wildtype groups. The levels of an immature neuronal marker were upregulated in mutants, while a glial marker showed an overall reduction. Mutants had preserved levels of inhibitory and presynaptic elements with aging, whereas glutamate receptor subunit levels declined. CONCLUSION Long-term AChE activity depletion induces synaptic and cellular alterations. These data provide further insights into molecular targets and adaptive responses following the long-term reduction of AChE activity that was also targeted pharmacologically to treat neurodegenerative diseases in human subjects.
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Affiliation(s)
- Elif Tugce Karoglu-Eravsar
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
- Department of Psychology, Selcuk University, Konya, Turkey
| | - Melek Umay Tuz-Sasik
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
| | - Aysenur Karaduman
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Ayse Gokce Keskus
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
| | - Ayca Arslan-Ergul
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
| | - Ozlen Konu
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Hulusi Kafaligonul
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Michelle M. Adams
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
- National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology (UNAM), Bilkent University, Ankara, Turkey
- Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
- Department of Psychology, Bilkent University, Ankara, Turkey
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Pereira PA, Millner T, Vilela M, Sousa S, Cardoso A, Madeira MD. Nerve growth factor-induced plasticity in medial prefrontal cortex interneurons of aged Wistar rats. Exp Gerontol 2016; 85:59-70. [DOI: 10.1016/j.exger.2016.09.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/04/2016] [Accepted: 09/20/2016] [Indexed: 01/03/2023]
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Cassel JC, Lazaris A, Birthelmer A, Jackisch R. Spatial reference- (not working- or procedural-) memory performance of aged rats in the water maze predicts the magnitude of sulpiride-induced facilitation of acetylcholine release by striatal slices. Neurobiol Aging 2007; 28:1270-85. [PMID: 16843572 DOI: 10.1016/j.neurobiolaging.2006.05.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 05/18/2006] [Accepted: 05/30/2006] [Indexed: 11/17/2022]
Abstract
Cluster analysis of water-maze reference-memory performance distinguished subpopulations of young adult (3-5 months), aged (25-27 months) unimpaired (AU) and aged impaired (AI) rats. Working-memory performances of AU and AI rats were close to normal (though young and aged rats differed in exploration strategies). All aged rats showed impaired procedural-memory. Electrically evoked release of tritium was assessed in striatal slices (preloaded with [(3)H]choline) in the presence of oxotremorine, physostigmine, atropine+physostigmine, quinpirole, nomifensine or sulpiride. Aged rats exhibited reduced accumulation of [(3)H]choline (-30%) and weaker transmitter release. Drug effects (highest concentration) were reductions of release by 44% (oxotremorine), 72% (physostigmine), 84% (quinpirole) and 65% (nomifensine) regardless of age. Sulpiride and atropine+physostigmine facilitated the release more efficiently in young rats versus aged rats. The sulpiride-induced facilitation was weaker in AI rats versus AU rats; it significantly correlated with reference-memory performance. The results confirm age-related alterations of cholinergic and dopaminergic striatal functions, and point to the possibility that alterations in the D(2)-mediated dopaminergic regulation of these functions contribute to age-related reference-memory deficits.
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Affiliation(s)
- Jean-Christophe Cassel
- Laboratoire de Neurosciences Comportementales et Cognitives, FRE 2855, CNRS-Université Louis Pasteur, IFR 37 Neurosciences, GDR CNRS 2905, Strasbourg, France.
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Cassel JC, Schweizer T, Lazaris A, Knörle R, Birthelmer A, Gödtel-Armbrust U, Förstermann U, Jackisch R. Cognitive deficits in aged rats correlate with levels of L-arginine, not with nNOS expression or 3,4-DAP-evoked transmitter release in the frontoparietal cortex. Eur Neuropsychopharmacol 2005; 15:163-75. [PMID: 15695061 DOI: 10.1016/j.euroneuro.2004.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Revised: 08/28/2004] [Accepted: 09/05/2004] [Indexed: 01/26/2023]
Abstract
Aging is associated with altered neurotransmitter function in the brain. In this study, we measured release parameters for acetylcholine (ACh), norepinephrine and serotonin in the frontoparietal cortex of young and aged rats. We also determined cortical amino acid concentrations and nitric oxide (NO) synthase function. Prior to sacrifice, the rats had been tested for Morris water-maze performance. In aged, compared with young rats, we observed a reduction in both uptake of choline and acetylcholine release. Serotonin release and L-arginine concentrations (a precursor of NO) showed an aging-related increase; however, L-citrulline/L-arginine ratios were decreased in aged rats. Moreover, while most age-related changes in transmitter release or neurochemical markers were not related to the learning performance, L-arginine concentrations were positively correlated to cognitive deficits. NO synthase concentrations were not affected by aging. It is suggested that events related to L-arginine-to-L-citrulline/NO metabolism in the frontoparietal cortex may take part in age-related cognitive deficits.
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Affiliation(s)
- Jean-Christophe Cassel
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany.
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Schweizer T, Birthelmer A, Lazaris A, Cassel JC, Jackisch R. 3,4-DAP-evoked transmitter release in hippocampal slices of aged rats with impaired memory. Brain Res Bull 2003; 62:129-36. [PMID: 14638386 DOI: 10.1016/j.brainresbull.2003.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Based on a slice superfusion technique, this study investigated the release of acetylcholine, noradrenaline and serotonin in the hippocampus of aged rats (25-27 months) showing no or severe deficits in a spatial reference-memory task (water maze). Young adults (3-5 months) were used as controls. 3,4-diaminopyridine (3,4-DAP), a potassium channel antagonist which increases neuronal excitability, was used to evoke the overflow of the three neurotransmitters. The release of [3H]noradrenaline induced by stimulation of presynaptic nicotinic receptors was also assessed. The experiment compared the accumulation and 3,4-DAP-evoked (or nicotine-evoked) overflow of [3H] in hippocampal slices preincubated with [3H]choline, [3H]noradrenaline, or [3H]serotonin. In aged rats, only the accumulation of [3H]serotonin was reduced significantly (-17%). In percent of tissue-[3H], the 3,4-DAP-evoked overflow of [3H]serotonin was increased (+28%), and that of [3H]acetylcholine was reduced (-23%) in the aged rats. The nicotine-evoked overflow of [3H]noradrenaline was not altered in aged rats. There was a significant correlation of water-maze performance (distance to platform) and evoked overflow of [3H]serotonin. It is concluded that hippocampal cholinergic functions are more altered by aging than noradrenergic or serotonergic ones. Excessive excitability of serotonergic terminals, perhaps in addition to cholinergic dysfunction, might be a crucial factor accounting for age-related cognitive deficits in the present population of rats.
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Affiliation(s)
- Theresa Schweizer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany
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Birthelmer A, Stemmelin J, Jackisch R, Cassel JC. Presynaptic modulation of acetylcholine, noradrenaline, and serotonin release in the hippocampus of aged rats with various levels of memory impairments. Brain Res Bull 2003; 60:283-96. [PMID: 12754090 DOI: 10.1016/s0361-9230(03)00042-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aged (25-27 months) Long-Evans female rats were distinguished according to whether they showed no significant impairment (AU), moderate impairment (AMI), or severe impairment (ASI) in a spatial reference-memory task. Young (3-5 months) rats served as controls. Electrically evoked overflow of tritium was assessed in hippocampal slices preloaded with [3H]choline or [3H]serotonin (5-HT). Nicotine-evoked overflow of tritium was measured after preloading with [3H]noradrenaline (NA). Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity, and concentration of monoamines were assessed in homogenates. Aged rats exhibited reduced accumulation of [3H]choline and [3H]5-HT, increased accumulation of [3H]NA, and weaker electrically evoked overflow of [3H]acetylcholine ([3H]ACh) and [3H]5-HT. The overflow of [3H]NA was not altered consistently by aging. Roughly, drugs acting presynaptically had comparable effects in aged rats: oxotremorine and CP 93,129 inhibited the overflow of [3H]ACh, CP 93,129 and UK 14,304 reduced that of [3H]5-HT. ChAT or AChE activity, and 5-HT concentration were not changed by age; NA concentration was reduced. When significant, changes were comparable in AU, AMI, and ASI rats. Data show that aging alters cholinergic and serotonergic hippocampal innervations, release of ACh and 5-HT, but not presynaptic release-modulating mechanisms. These alterations do not account for variability in water-maze performance of aged rats.
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Affiliation(s)
- A Birthelmer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie der Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany
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8
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Birthelmer A, Lazaris A, Schweizer T, Jackisch R, Cassel JC. Presynaptic regulation of neurotransmitter release in the cortex of aged rats with differential memory impairments. Pharmacol Biochem Behav 2003; 75:147-62. [PMID: 12759123 DOI: 10.1016/s0091-3057(03)00065-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cluster analysis of water-maze reference-memory performances of 25-27-month-old (compared to 3-5-month-old) rats distinguished subpopulations of young adult rats (YOUNG), aged rats with no significant impairment (AU), aged rats with moderate impairment (AMI), and aged rats with severe impairment (ASI). In the frontoparietal cortex, we subsequently assessed the electrically evoked release of tritium in slices preloaded with [3H]choline, [3H]noradrenaline (NA), or [3H]serotonin (5-HT) and the effects of an agonist (oxotremorine, UK 14,304, and CP 93,129) of the respective autoreceptors. Cholinergic and monoaminergic markers were measured in homogenates. Overall, aged rats exhibited reduced accumulation of [3H]choline (-25%) and weaker evoked transmitter release (in % of accumulated tritium: -44%, -20%, and -34%, for [3H]acetylcholine, [3H]NA, and [3H]5-HT, respectively). In all rats, the inhibitory effects of the autoreceptor agonists on the evoked release of [3H] were comparable. Acetylcholinesterase (AChE), not choline acetyltransferase (ChAT), activity was reduced. The results suggest age-related modifications in the cholinergic, noradrenergic, and serotonergic innervation of the frontoparietal cortex, alterations of evoked transmitter release, but no interference with presynaptic autoinhibition of the release. Neither of these alterations seemed to account for the cognitive impairment assessed.
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Affiliation(s)
- A Birthelmer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany
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Abstract
Choline has many physiological functions throughout the body that are dependent on its available local supply. However, since choline is a charged hydrophilic cation, transport mechanisms are required for it to cross biological membranes. Choline transport is required for cellular membrane construction and is the rate-limiting step for acetylcholine production. Transport mechanisms include: (1) sodium-dependent high-affinity uptake mechanism in synaptosomes, (2) sodium-independent low-affinity mechanism on cellular membranes, and (3) unique choline uptake mechanisms (e.g., blood-brain barrier choline transport). A comprehensive overview of choline transport studies is provided. This review article examines landmark and current choline transport studies, molecular mapping, and molecular identification of these carriers. Information regarding the choline-binding site is presented by reviewing choline structural analog (hemicholinium-3 and 15, and other nitrogen/methyl-hydroxyl compounds) inhibition studies. Choline transport in Alzheimer's disease, brain ischemic events, and aging is also discussed. Emphasis throughout the article is placed on targeting the choline transporter in disease and use of this carrier as a drug delivery vector.
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Affiliation(s)
- P R Lockman
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79106-1712, USA
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Araki T, Kato H, Shuto K, Fujiwara T, Itoyama Y. Effects of vinconate on neurotransmitter receptor systems in aged rat brain. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 1996; 2:343-349. [PMID: 21781741 DOI: 10.1016/s1382-6689(96)00068-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/1996] [Revised: 08/09/1996] [Accepted: 08/12/1996] [Indexed: 05/31/2023]
Abstract
We investigated the effects of age and (±)-methyl-3-ethyl-2,3,3a,4-tetrahydro-1 H-indolo[3,2,1-de][1,5]naphthyridine-6-carboxylate hydrochloride (vinconate), an indolonaphthyridine derivative, on neurotransmitter receptor systems in the rat brain using quantitative receptor autoradiography. [(3)H]Quinuclidinyl benzilate (QNB), [(3)H]hemicholinium-3 (HC) and [(3)H]muscimol were used to label acetylcholine receptors, high-affinity choline uptake sites and γ-aminobutyric acid(A) (GABA(A)) receptors, respectively. [(3)H]QNB, [(3)H]HC and [(3)H]muscimol binding decreased in any brain areas of 24-month-old (aged) rats in comparison with 6-month-old (adult) animals. Chronic treatment with vinconate (10 and 30 mg/kg, i.p., once a day for 4 weeks) partly ameliorated the reduction in [(3)H]QNB, [(3)H]HC and [(3)H]muscimol biding in aged rat brains. This effect was especially noted in [(3)H]muscimol binding. The results suggest that vinconate may have beneficial effects on age-related changes in neurotransmitter receptor systems.
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Affiliation(s)
- T Araki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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Araki T, Kato H, Fujiwara T, Itoyama Y. Regional age-related alterations in cholinergic and GABAergic receptors in the rat brain. Mech Ageing Dev 1996; 88:49-60. [PMID: 8803921 DOI: 10.1016/0047-6374(96)01720-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The age-related changes of cholinergic and gamma-aminobutyric acid (GABA)ergic receptors were studied in 3-week- and 6-, 12-, 18- and 24-month-old Fisher 344 male rat brains using receptor autoradiography. [3H]Quinuclidinyl benzilate (QNB), [3H]hemicholinium-3 (HC) and [3H]muscimol were used to label acetylcholine receptors, acetylcholine reuptake sites and GABAA receptors, respectively. In immature rats (3-week-old), [3H]QNB and [3H]muscimol binding showed a significant increase in most brain areas, compared to adult young animals (6-month-old), whereas [3H]HC binding exhibited a significant increase only in the dentate gyrus, substantia nigra and cerebellum. In contrast, [3H]QNB and [3H]HC binding showed no significant changes in all brain areas during aging. On the other hands, [3H]muscimol binding showed a significant reduction in the substantia nigra and cerebellum of adult mature rats (12-month-old). Thereafter, the age-related reduction in [3H]muscimol binding was observed in all brain areas of aged rats (24-month-old). Our results demonstrate that the GABAergic system is susceptible to aging processes in the central nervous system, whereas the cholinergic system is unaltered by aging. Furthermore, our results suggest significant regional changes in both GABAergic and cholinergic systems in the brain even 3 weeks after birth. These findings suggest that the disturbance in GABAergic-cholinergic interactions may play a key role in age-related neurological deficits and cognitive dysfunction.
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Affiliation(s)
- T Araki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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Moore H, Stuckman S, Sarter M, Bruno JP. Potassium, but not atropine-stimulated cortical acetylcholine efflux, is reduced in aged rats. Neurobiol Aging 1996; 17:565-71. [PMID: 8832631 DOI: 10.1016/0197-4580(96)00075-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Using in vivo microdialysis, cortical acetylcholine (ACh) efflux was measured in freely moving Brown Norway/Fischer 344 F1 rats, aged 4 or 22 months. The effects of local, intracortical perfusion of atropine (1.0 or 100.0 microM) via the dialysis probe were compared to local K+ (100.0 mM) stimulation in the presence of elevated extracellular Ca2+ (2.5 mM). Basal cortical ACh efflux in aged rats was similar to that of young animals. Administration of atropine (1.0 or 100.0 microM) via the cortical dialysis probe substantially increased cortical ACh efflux, but did not differentially stimulate ACh efflux in young and aged rats. In contrast, ACh efflux stimulated locally with K+ and Ca2+ was significantly reduced in aged rats relative to young adults. The implications of the dissociable effects of K(+)-depolarization and muscarinic blockade for local regulation of cortical ACh efflux in aged animals are discussed.
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Affiliation(s)
- H Moore
- Department of Psychology, Ohio State University, Columbus 43210 USA
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Aubert I, Rowe W, Meaney MJ, Gauthier S, Quirion R. Cholinergic markers in aged cognitively impaired Long-Evans rats. Neuroscience 1995; 67:277-92. [PMID: 7675169 DOI: 10.1016/0306-4522(95)00056-o] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Aged Long-Evans rats (24-25 months old) were classified into cognitively impaired or unimpaired subgroups based on their performances in the Morris Swim Maze task compared to young controls. Using quantitative in vitro receptor autoradiography, we investigated the status of various cholinergic markers in these two groups and in young adults (six months) animals. The apparent density of [3H]pirenzepine (muscarinic M1) sites was similar in the three groups of rats in various cortical areas, subfields of the hippocampus, medial septum and striatum. Similarly, choline acetyltransferase activity and the density of [3H]hemicholinium-3 (high-affinity choline uptake) and [3H]cytisine (nicotinic) binding sites were also unchanged in the brain regions studied between the aged cognitively impaired, unimpaired and young adult rats. In contrast, significant increases in [3H]AF-DX 384 (muscarinic M2) binding density were observed in various cortical areas and in the molecular layer of the dentate gyrus of aged cognitively impaired versus unimpaired rats and in few cortical regions of old as compared to young animals. Therefore, a selective alteration in the regulation of putative M2 receptor sites is apparent, particularly in the aged cognitively impaired rats. Increases in M2 binding sites could lead to a decrease in the capacity to release acetylcholine, as some of the M2 receptors are believed to act as negative autoreceptors. This could influence cognitive functions as selective M2 blockers have recently been reported to facilitate spatial memory in aged impaired rats [Doods et al. (1993) Life Sci. 52, 497-503: Quirion et al. (1995) J. Neurosci. 15, 1455-1462.
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Affiliation(s)
- I Aubert
- Department of Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada
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Yufu F, Egashira T, Yamanaka Y. Age-related changes of cholinergic markers in the rat brain. JAPANESE JOURNAL OF PHARMACOLOGY 1994; 66:247-55. [PMID: 7869609 DOI: 10.1254/jjp.66.247] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To evaluate whether any degenerative changes affect the brain cholinergic systems during natural aging, we compared various cholinergic biochemical markers (number of muscarinic receptors, mAChR; choline acetyltransferase activity, ChAT; acetylcholinesterase activity, AChE; and sodium-dependent high affinity choline uptake) in the cortical (CR) and subcortical (SS) regions of the brains of aged (24 month) and young (2 month) rats. Using [3H]-quinuclidinyl benzilate ([3H]-QNB) as the ligand of muscarinic receptor binding, the numbers of mAChR decreased about 30% in both the CR and the SS of aged rats compared with those in young rats, while a significant age-related increase in the affinity of mAChR was observed. [3H]-QNB binding in both the young and aged rat brain was displaced markedly by pirenzepine, while [3H]-QNB binding in the SS of the aged rat brain was displaced at low concentrations of atropine. The Vmax values of ChAT and AChE also decreased about 20-30% compared with those of young rats. The sodium-dependent high affinity choline uptake was lower in the crude synaptosomal fraction prepared from aged rat brain than in young brain. Hemicholinium-3 inhibited the choline uptake in young rat brain at a concentration range of 1 microM-10 nM, but choline uptake in aged brain was insensitive to hemicholinium-3. These results indicate that natural aging brings about a diffuse and multiple depletion of various biochemical markers in cholinergic neurons.
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Affiliation(s)
- F Yufu
- Department of Pharmacology, Oita Medical University, Japan
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Pepeu G, Giovannelli L. The central cholinergic system during aging. PROGRESS IN BRAIN RESEARCH 1994; 100:67-71. [PMID: 7938536 DOI: 10.1016/s0079-6123(08)60770-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- G Pepeu
- Department of Preclinical and Clinical Pharmacology, University of Florence, Italy
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