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Crimins JL, Puri R, Calakos KC, Yuk F, Janssen WGM, Hara Y, Rapp PR, Morrison JH. Synaptic distributions of pS214-tau in rhesus monkey prefrontal cortex are associated with spine density, but not with cognitive decline. J Comp Neurol 2019; 527:856-873. [PMID: 30408169 PMCID: PMC6333519 DOI: 10.1002/cne.24576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/18/2018] [Accepted: 10/21/2018] [Indexed: 12/31/2022]
Abstract
Female rhesus monkeys and women are subject to age- and menopause-related deficits in working memory, an executive function mediated by the dorsolateral prefrontal cortex (dlPFC). Long-term cyclic administration of 17β-estradiol improves working memory, and restores highly plastic axospinous synapses within layer III dlPFC of aged ovariectomized monkeys. In this study, we tested the hypothesis that synaptic distributions of tau protein phosphorylated at serine 214 (pS214-tau) are altered with age or estradiol treatment, and couple to working memory performance. First, ovariectormized young and aged monkeys received vehicle or estradiol treatment, and were tested on the delayed response (DR) test of working memory. Serial section electron microscopic immunocytochemistry was then performed to quantitatively assess the subcellular synaptic distributions of pS214-tau. Overall, the majority of synapses contained pS214-tau immunogold particles, which were predominantly localized to the cytoplasm of axon terminals. pS214-tau was also abundant within synaptic and cytoplasmic domains of dendritic spines. The density of pS214-tau immunogold within the active zone, cytoplasmic, and plasmalemmal domains of axon terminals, and subjacent to the postsynaptic density within the subsynaptic domains of dendritic spines, were each reduced with age. None of the variables examined were directly linked to cognitive status, but a high density of pS214-tau immunogold particles within presynaptic cytoplasmic and plasmalemmal domains, and within postsynaptic subsynaptic and plasmalemmal domains, accompanied high synapse density. Together, these data support a possible physiological, rather than pathological, role for pS214-tau in the modulation of synaptic morphology in monkey dlPFC.
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Affiliation(s)
- Johanna L. Crimins
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Rishi Puri
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Katina C. Calakos
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Frank Yuk
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - William G. M. Janssen
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Yuko Hara
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Peter R. Rapp
- National Institute on Aging, Laboratory of Behavioral Neuroscience, Baltimore, MD 21224
| | - John H. Morrison
- Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Department of Geriatrics and Palliative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- California National Primate Research Center, Davis, CA 95616
- Department of Neurology, School of Medicine, University of California, Davis, CA 95616
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Beuk J, Beninger RJ, Paré M. Lifespan Changes in the Countermanding Performance of Young and Middle Aged Adult Rats. Front Aging Neurosci 2016; 8:190. [PMID: 27555818 PMCID: PMC4977309 DOI: 10.3389/fnagi.2016.00190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/26/2016] [Indexed: 01/19/2023] Open
Abstract
Inhibitory control can be investigated with the countermanding task, which requires subjects to make a response to a go signal and cancel that response when a stop signal is presented occasionally. Adult humans performing the countermanding task typically exhibit impaired response time (RT), stop signal response time (SSRT) and response accuracy as they get older, but little change in post-error slowing. Rodent models of the countermanding paradigm have been developed recently, yet none have directly examined age-related changes in performance throughout the lifespan. Male Wistar rats (N = 16) were trained to respond to a visual stimulus (go signal) by pressing a lever directly below an illuminated light for food reward, but to countermand the lever press subsequent to a tone (stop signal) that was presented occasionally (25% of trials) at a variable delay. Subjects were tested in 1 h sessions at approximately 7 and 12 months of age with intermittent training in between. Rats demonstrated longer go trial RT, a higher proportion of go trial errors and performed less total trials at 12, compared to 7 months of age. Consistent SSRT and post-error slowing were observed for rats at both ages. These results suggest that the countermanding performance of rats does vary throughout the lifespan, in a manner similar to humans, suggesting that rodents may provide a suitable model for behavioral impairment related to normal aging. These findings also highlight the importance of indicating the age at which rodents are tested in countermanding investigations.
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Affiliation(s)
- Jonathan Beuk
- Centre for Neuroscience Studies, Queen's University Kingston, ON, Canada
| | - Richard J Beninger
- Centre for Neuroscience Studies, Queen's UniversityKingston, ON, Canada; Department of Psychology, Queen's UniversityKingston, ON, Canada
| | - Martin Paré
- Centre for Neuroscience Studies, Queen's UniversityKingston, ON, Canada; Department of Biomedical and Molecular Sciences, Queen's UniversityKingston, ON, Canada
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Liguz-Lecznar M, Lehner M, Kaliszewska A, Zakrzewska R, Sobolewska A, Kossut M. Altered glutamate/GABA equilibrium in aged mice cortex influences cortical plasticity. Brain Struct Funct 2016; 220:1681-93. [PMID: 24659256 DOI: 10.1007/s00429-014-0752-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 03/07/2014] [Indexed: 11/25/2022]
Abstract
Age-related molecular changes in the synapse can cause plasticity decline. We found an impairment of experience-dependent cortical plasticity is induced by short lasting sensory conditioning in aged mice. However, extending the training procedure from 3 to 7 days triggered plasticity in the aged cortex of the same range as in young mice. Additionally, GABAergic markers (GABA, GAD67, VGAT) in young and aged groups that showed the plastic changes were upregulated. This effect was absent in the aged group with impaired plasticity, while the expression of Vglut1 increased in all trained groups. This may reflect the inefficiency of inhibitory mechanisms in the aging brain used to control increased excitation after training and to shape proper signal to noise ratio, which is essential for appropriate stimuli processing. HPLC analysis showed that the glutamate/GABA ratio was significantly reduced in aged animals due to a significant decrease in glutamate level. We also observed a decreased expression of several presynaptic markers involved in excitatory (vesicular glutamate transporter-vglut2) and inhibitory (glutamic acid decarboxylase-GAD67, vesicular GABA transporter VGAT) transmission in the aged barrel cortex. These changes may weaken the plasticity potential of neurons and impede the experience-dependent reorganization of cortical connections. We suggest that the imbalance toward inhibition resulting from a decrease of glutamate content in the aging cerebral cortex, together with GABAergic system ineffectiveness in upregulating GABA level after sensory training, contributes to the impairment of learning-dependent cortical plasticity.
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Collier TJ, O'Malley J, Rademacher DJ, Stancati JA, Sisson KA, Sortwell CE, Paumier KL, Gebremedhin KG, Steece-Collier K. Interrogating the aged striatum: robust survival of grafted dopamine neurons in aging rats produces inferior behavioral recovery and evidence of impaired integration. Neurobiol Dis 2015; 77:191-203. [PMID: 25771169 PMCID: PMC4402284 DOI: 10.1016/j.nbd.2015.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 01/13/2023] Open
Abstract
Advanced age is the primary risk factor for Parkinson's disease (PD). In PD patients and rodent models of PD, advanced age is associated with inferior symptomatic benefit following intrastriatal grafting of embryonic dopamine (DA) neurons, a pattern believed to result from decreased survival and reinnervation provided by grafted neurons in the aged host. To help understand the capacity of the aged, parkinsonian striatum to be remodeled with new DA terminals, we used a grafting model and examined whether increasing the number of grafted DA neurons in aged rats would translate to enhanced behavioral recovery. Young (3months), middle-aged (15months), and aged (22months) parkinsonian rats were grafted with proportionately increasing numbers of embryonic ventral mesencephalic (VM) cells to evaluate whether the limitations of the graft environment in subjects of advancing age can be offset by increased numbers of transplanted neurons. Despite robust survival of grafted neurons in aged rats, reinnervation of striatal neurons remained inferior and amelioration of levodopa-induced dyskinesias (LID) was delayed or absent. This study demonstrates that: 1) counter to previous evidence, under certain conditions the aged striatum can support robust survival of grafted DA neurons; and 2) unknown factors associated with the aged striatum result in inferior integration of graft and host, and continue to present obstacles to full therapeutic efficacy of DA cell-based therapy in this model of aging.
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Affiliation(s)
- Timothy J Collier
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Jennifer O'Malley
- Cincinnati Children's Hospital Medical Center, Division of Child Neurology, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - David J Rademacher
- Lake Forest College, Department of Psychology, 555 N Sheridan Rd, Lake Forest, IL 60045, USA
| | - Jennifer A Stancati
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Kellie A Sisson
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Caryl E Sortwell
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Katrina L Paumier
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Kibrom G Gebremedhin
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Kathy Steece-Collier
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA.
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Abstract
What is the neuroanatomical basis for the decline in brain function that occurs during normal aging? Previous postmortem studies have blamed it on a reduction in spine density, though results remain controversial and spine dynamics were not assessed. We used chronic in vivo two-photon imaging of dendritic spines and axonal boutons in somatosensory cortex for up to 1 year in thy1 GFP mice to test the hypothesis that aging is associated with alterations in synaptic dynamics. We find that the density of spines and en passant boutons (EPBs) in pyramidal cells increases throughout adult life but is stable between mature (8-15 months) and old (>20 months) mice. However, new spines and EPBs are two to three times more likely to be stabilized over 30 d in old mice, although the long-term retention (over months) of stable spines is lower in old animals. In old mice, spines are smaller on average but are still able to make synaptic connections regardless of their size, as assessed by serial section electron microscopy reconstructions of previously imaged dendrites. Thus, our data suggest that age-related deficits in sensory perception are not associated with synapse loss in somatosensory cortex (as might be expected) but with alterations in the size and stability of spines and boutons observed in this brain area. The changes we describe here likely result in weaker synapses that are less capable of short-term plasticity in aged individuals, and therefore to less efficient circuits.
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Dickstein DL, Weaver CM, Luebke JI, Hof PR. Dendritic spine changes associated with normal aging. Neuroscience 2012; 251:21-32. [PMID: 23069756 DOI: 10.1016/j.neuroscience.2012.09.077] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/25/2012] [Accepted: 09/27/2012] [Indexed: 12/14/2022]
Abstract
Given the rapid rate of population aging and the increased incidence of cognitive decline and neurodegenerative diseases with advanced age, it is important to ascertain the determinants that result in cognitive impairment. It is also important to note that much of the aged population exhibit 'successful' cognitive aging, in which cognitive impairment is minimal. One main goal of normal aging studies is to distinguish the neural changes that occur in unsuccessful (functionally impaired) subjects from those of successful (functionally unimpaired) subjects. In this review, we present some of the structural adaptations that neurons and spines undergo throughout normal aging and discuss their likely contributions to electrophysiological properties and cognition. Structural changes of neurons and dendritic spines during aging, and the functional consequences of such changes, remain poorly understood. Elucidating the structural and functional synaptic age-related changes that lead to cognitive impairment may lead to the development of drug treatments that can restore or protect neural circuits and mediate cognition and successful aging.
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Affiliation(s)
- D L Dickstein
- Fishberg Department of Neuroscience, Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY 10029, USA; Computational Neurobiology and Imaging Center, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Akopian G, Walsh JP. Pre- and postsynaptic contributions to age-related alterations in corticostriatal synaptic plasticity. Synapse 2006; 60:223-38. [PMID: 16739119 DOI: 10.1002/syn.20289] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Aging creates deficits in motor performance related to changes in striatal processing of cortical information. This study describes age-related changes in corticostriatal snaptic plasticity and associated mechanisms, which may contribute to declines in motor behavior. Intracellular recordings revealed an age-related decrease in the expression of paired-pulse, posttetanic, and long-term potentiation (LTP). The age-related difference in LTP was associated with reduced sensitivity to block of N-methyl-D-aspartate (NMDA) receptors in the aged population. These age-related changes could not be explained by increased L-type Ca(2+)channel activity, since block of L-type Ca(2+) channels with nifedipine increased rather than decreased the age-related difference in long-term plasticity. Age-related increases in reactive oxygen species (ROS) modulation were also ruled out, since application of H(2)O(2) produced changes in synaptic function that were opposite to trends seen in aging, and addition of the antioxidant Trolox-C had a larger effect on long-term plasticity in young rats than in older rats. A robust age-related difference in long-term synaptic plasticity was found by studying synaptic plasticity following the blocking of D2 receptors with l-sulpiride, which may involve age-difference in NMDA receptor function. l-sulpiride consistently enabled a slow development of LTP at young (but not aged) corticostriatal synapses. However, No age differences were found in the sensitivity to the addition of the D2 receptor agonist quinpirole. These findings provide evidence for age-induced changes in the release properties of cortical terminals and in the functioning of postsynaptic striatal NMDA receptors, which may contribute to age-related deficits in striatum control of movement.
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Affiliation(s)
- G Akopian
- Andrus Gerontology Center, USC Program in Neuroscience, University of Southern California, Los Angeles, California 90089-0191, USA
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8
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Rodrigues RJ, Alfaro TM, Rebola N, Oliveira CR, Cunha RA. Co-localization and functional interaction between adenosine A(2A) and metabotropic group 5 receptors in glutamatergic nerve terminals of the rat striatum. J Neurochem 2005; 92:433-41. [PMID: 15659214 DOI: 10.1111/j.1471-4159.2004.02887.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The anti-Parkinsonian effect of glutamate metabotropic group 5 (mGluR5) and adenosine A(2A) receptor antagonists is believed to result from their ability to postsynaptically control the responsiveness of the indirect pathway that is hyperfunctioning in Parkinson's disease. mGluR5 and A(2A) antagonists are also neuroprotective in brain injury models involving glutamate excitotoxicity. Thus, we hypothesized that the anti-Parkinsonian and neuroprotective effects of A(2A) and mGluR5 receptors might be related to their control of striatal glutamate release that actually triggers the indirect pathway. The A(2A) agonist, CGS21680 (1-30 nM) facilitated glutamate release from striatal nerve terminals up to 57%, an effect prevented by the A(2A) antagonist, SCH58261 (50 nM). The mGluR5 agonist, CHPG (300-600 mum) also facilitated glutamate release up to 29%, an effect prevented by the mGluR5 antagonist, MPEP (10 microm). Both mGluR5 and A(2A) receptors were located in the active zone and 57 +/- 6% of striatal glutamatergic nerve terminals possessed both A(2A) and mGluR5 receptors, suggesting a presynaptic functional interaction. Indeed, submaximal concentrations of CGS21680 (1 nM) and CHPG (100 microm) synergistically facilitated glutamate release and the facilitation of glutamate release by 10 nM CGS21680 was prevented by 10 microm MPEP, whereas facilitation by 300 microm CHPG was prevented by 10 nM SCH58261. These results provide the first direct evidence that A(2A) and mGluR5 receptors are co-located in more than half of the striatal glutamatergic terminals where they facilitate glutamate release in a synergistic manner. This emphasizes the role of the modulation of glutamate release as a likely mechanism of action of these receptors both in striatal neuroprotection and in Parkinson's disease.
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Affiliation(s)
- Ricardo J Rodrigues
- Centre for Neuroscience of Coimbra, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
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Abstract
Male Fischer 344 rats aged 3, 6, 12, 18 and 24 months were trained to walk on a narrow beam, then lesioned in the right hindlimb sensorimotor cortex by photothrombosis. Motor performance was measured daily for 60 days using a 7-point rating scale from which deficit scores were calculated. Tissue analysis included lesion volume measurement after Nissl staining. Animals aged 3 and 6 months fully recovered by day 10 and 31, respectively. Animals aged 18 months acquired significant neurological impairment that persisted greater than 60 days. Deficit scores were significantly greater than in groups aged 12, 6 and 3 months. Degenerative morbidity and mortality confounded behavioral study of animals aged 24 months. The duration of neurological impairment after photochemical sensorimotor cortex lesion increased with age. Animals aged 18 months at lesion acquired the greatest chronic impairment. This aged post-acute animal model is clinically relevant to stroke rehabilitation.
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Affiliation(s)
- Allen W Brown
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA.
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