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Sagheddu C, Stojanovic T, Kouhnavardi S, Savchenko A, Hussein AM, Pistis M, Monje FJ, Plasenzotti R, Aufy M, Studenik CR, Lubec J, Lubec G. Cognitive performance in aged rats is associated with differences in distinctive neuronal populations in the ventral tegmental area and altered synaptic plasticity in the hippocampus. Front Aging Neurosci 2024; 16:1357347. [PMID: 38469164 PMCID: PMC10926450 DOI: 10.3389/fnagi.2024.1357347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 02/12/2024] [Indexed: 03/13/2024] Open
Abstract
Introduction Deterioration of cognitive functions is commonly associated with aging, although there is wide variation in the onset and manifestation. Albeit heterogeneity in age-related cognitive decline has been studied at the cellular and molecular level, there is poor evidence for electrophysiological correlates. The aim of the current study was to address the electrophysiological basis of heterogeneity of cognitive functions in cognitively Inferior and Superior old (19-20 months) rats in the ventral tegmental area (VTA) and the hippocampus, having Young (12 weeks) rats as a control. The midbrain VTA operates as a hub amidst affective and cognitive facets, processing sensory inputs related to motivated behaviours and hippocampal memory. Increasing evidence shows direct dopaminergic and non-dopaminergic input from the VTA to the hippocampus. Methods Aged Superior and Inferior male rats were selected from a cohort of 88 animals based on their performance in a spatial learning and memory task. Using in vivo single-cell recording in the VTA, we examined the electrical activity of different neuronal populations (putative dopaminergic, glutamatergic and GABAergic neurons). In the same animals, basal synaptic transmission and synaptic plasticity were examined in hippocampal slices. Results Electrophysiological recordings from the VTA and hippocampus showed alterations associated with aging per se, together with differences specifically linked to the cognitive status of aged animals. In particular, the bursting activity of dopamine neurons was lower, while the firing frequency of glutamatergic neurons was higher in VTA of Inferior old rats. The response to high-frequency stimulation in hippocampal slices also discriminated between Superior and Inferior aged animals. Discussion This study provides new insight into electrophysiological information underlying compromised cerebral ageing. Further understanding of brain senescence, possibly related to neurocognitive decline, will help develop new strategies towards the preservation of a high quality of life.
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Affiliation(s)
- Claudia Sagheddu
- Division of Neuroscience and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Tamara Stojanovic
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
| | - Shima Kouhnavardi
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Artem Savchenko
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
- Institute of Pharmacology, Pavlov First Saint Petersburg State Medical University, St. Petersburg, Russia
| | - Ahmed M. Hussein
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
- Department of Zoology, Faculty of Science, Al-Azhar University, Asyut, Egypt
| | - Marco Pistis
- Division of Neuroscience and Clinical Pharmacology, Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
- Section of Cagliari, Neuroscience Institute National Research Council of Italy (CNR), Cagliari, Italy
- Unit of Clinical Pharmacology, University Hospital, Cagliari, Italy
| | - Francisco J. Monje
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Roberto Plasenzotti
- Division of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Mohammed Aufy
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Christian R. Studenik
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Jana Lubec
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
| | - Gert Lubec
- Programme for Proteomics, Paracelsus Medical University, Salzburg, Austria
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Engel MG, Smith J, Mao K, Quipildor GF, Cui MH, Gulinello M, Branch CA, Gandy SE, Huffman DM. Evidence for preserved insulin responsiveness in the aging rat brain. GeroScience 2022; 44:2491-2508. [PMID: 35798912 PMCID: PMC9768080 DOI: 10.1007/s11357-022-00618-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/27/2022] [Indexed: 01/06/2023] Open
Abstract
Insulin appears to exert salutary effects in the central nervous system (CNS). Thus, brain insulin resistance has been proposed to play a role in brain aging and dementia but is conceptually complex and unlikely to fit classic definitions established in peripheral tissues. Thus, we sought to characterize brain insulin responsiveness in young (4-5 months) and old (24 months) FBN male rats using a diverse set of assays to determine the extent to which insulin effects in the CNS are impaired with age. When performing hyperinsulinemic-euglycemic clamps in rats, intracerebroventricular (ICV) infusion of insulin in old animals improved peripheral insulin sensitivity by nearly two-fold over old controls and comparable to young rats, suggesting preservation of this insulin-triggered response in aging per se (p < 0.05). We next used an imaging-based approach by comparing ICV vehicle versus insulin and performed resting state functional magnetic resonance imaging (rs-fMRI) to evaluate age- and insulin-related changes in network connectivity within the default mode network. In aging, lower connectivity between the mesial temporal (MT) region and other areas, as well as reduced MT signal complexity, was observed in old rats, which correlated with greater cognitive deficits in old. Despite these stark differences, ICV insulin failed to elicit any significant alteration to the BOLD signal in young rats, while a significant deviation of the BOLD signal was observed in older animals, characterized by augmentation in regions of the septal nucleus and hypothalamus, and reduction in thalamus and nucleus accumbens. In contrast, ex vivo stimulation of hippocampus with 10 nM insulin revealed increased Akt activation in young (p < 0.05), but not old rats. Despite similar circulating levels of insulin and IGF-1, cerebrospinal fluid concentrations of these ligands were reduced with age. Thus, these data highlight the complexity of capturing brain insulin action and demonstrate preserved or heightened brain responses to insulin with age, despite dampened canonical signaling, thereby suggesting impaired CNS input of these ligands may be a feature of reduced brain insulin action, providing further rationale for CNS replacement strategies.
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Affiliation(s)
- Matthew G Engel
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Jeremy Smith
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Kai Mao
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Gabriela Farias Quipildor
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Min-Hui Cui
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Maria Gulinello
- Dominick S. Purpura Department of Neuroscience, Behavioral Core Facility, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Craig A Branch
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Samuel E Gandy
- Department of Neurology and the Mount Sinai Center for Cognitive Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry and the Mount Sinai Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Derek M Huffman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Li W, Wang S, Wang H, Wang J, Jin F, Fang F, Fang C. Astragaloside IV prevents memory impairment in D-galactose-induced aging rats via the AGEs/RAGE/ NF-κB axis. Arch Med Res 2021; 53:20-28. [PMID: 34217517 DOI: 10.1016/j.arcmed.2021.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 04/05/2021] [Accepted: 05/26/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND We investigated the effects of astragaloside IV (AS-IV) on memory function in aging rats mimicked by D-galactose administration and explored the potential molecular mechanisms. METHODS Twenty-seven male rats were randomly divided into control group (N = 9), model group (N = 9), and AS-IV treated group (N = 9). Aging model was stimulated by D-galactose (400 mg/kg/d, i.p., dissolved in saline) for 8 weeks in rats. The general status of the rats was observed weekly. Learning and memory function was determined using the eight-arm radical maze and step-down test. Pathological changes in the hippocampal CA1 region were determined by hematoxylin and eosin staining. Organ indexes, superoxide dismutase (SOD) activity and malonaldehyde (MDA) content in the serum were measured. Expression of advanced glycation end products (AGEs), receptor for AGEs (RAGE), nuclear factor-κB (NF-κB), interleukin (IL)-6, IL-1β and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay, real-time polymerase chain reaction or western blotting. RESULTS AS-IV improved the general status of the aging rats induced by D-galactose, prevented the impairment of memory function, organ indexes, and the pathological damage of the hippocampus. From the prospective of oxidative stress, AS-IV increased sera SOD activity and decreased MDA content. Additionally, AS-IV also reduced the inflammatory response by reducing hippocampal IL-1β, TNF-α, and IL-6 expression. Importantly, AS-IV prevented D-galactose-induced expression of AGEs, RAGE and NF-κB in the hippocampus. CONCLUSION AS-IV could prevent D-galactose-induced aging and memory impairment in rats, likely via regulation of inflammatory response, which was modulated by AGEs/RAGE/NF-κB axis.
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Affiliation(s)
- Wei Li
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Shuo Wang
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Hao Wang
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Jiepeng Wang
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Feng Jin
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Fang Fang
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China
| | - Chaoyi Fang
- Hebei University of Chinese Medicine, Shijiazhuang 050200, China; Hebei Key Laboratory of Chinese Medicine Research on Cardio-cerebrovascular Disease, Shijiazhuang 050091, China.
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