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Cognitive deficits and impaired hippocampal long-term potentiation in K ATP-induced DEND syndrome. Proc Natl Acad Sci U S A 2021; 118:2109721118. [PMID: 34732576 PMCID: PMC8609313 DOI: 10.1073/pnas.2109721118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
ATP-sensitive potassium (KATP) gain-of-function (GOF) mutations cause neonatal diabetes, with some individuals exhibiting developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome. Mice expressing KATP-GOF mutations pan-neuronally (nKATP-GOF) demonstrated sensorimotor and cognitive deficits, whereas hippocampus-specific hKATP-GOF mice exhibited mostly learning and memory deficiencies. Both nKATP-GOF and hKATP-GOF mice showed altered neuronal excitability and reduced hippocampal long-term potentiation (LTP). Sulfonylurea therapy, which inhibits KATP, mildly improved sensorimotor but not cognitive deficits in KATP-GOF mice. Mice expressing KATP-GOF mutations in pancreatic β-cells developed severe diabetes but did not show learning and memory deficits, suggesting neuronal KATP-GOF as promoting these features. These findings suggest a possible origin of cognitive dysfunction in DEND and the need for novel drugs to treat neurological features induced by neuronal KATP-GOF.
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2
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McNay EC, Pearson-Leary J. GluT4: A central player in hippocampal memory and brain insulin resistance. Exp Neurol 2020; 323:113076. [PMID: 31614121 PMCID: PMC6936336 DOI: 10.1016/j.expneurol.2019.113076] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 12/24/2022]
Abstract
Insulin is now well-established as playing multiple roles within the brain, and specifically as regulating hippocampal cognitive processes and metabolism. Impairments to insulin signaling, such as those seen in type 2 diabetes and Alzheimer's disease, are associated with brain hypometabolism and cognitive impairment, but the mechanisms of insulin's central effects are not determined. Several lines of research converge to suggest that the insulin-responsive glucose transporter GluT4 plays a central role in hippocampal memory processes, and that reduced activation of this transporter may underpin the cognitive impairments seen as a consequence of insulin resistance.
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Affiliation(s)
- Ewan C McNay
- Behavioral Neuroscience, University at Albany, Albany, NY, USA.
| | - Jiah Pearson-Leary
- Department of Anesthesiology, Abramson Research Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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3
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Sá JM, Barros MC, Melo MR, Colombari E, Menani JV, Colombari DSA. Endogenous hydrogen peroxide affects antidiuresis to cholinergic activation in the medial septal area. Neurosci Lett 2018; 694:51-56. [PMID: 30448293 DOI: 10.1016/j.neulet.2018.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/29/2018] [Accepted: 11/15/2018] [Indexed: 02/04/2023]
Abstract
Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis and antidiuresis. Hydrogen peroxide (H2O2) injected into the medial septal area (MSA) impairs behavioral and renal responses induced by carbachol at the same site, suggesting the exogenous H2O2 may modulate the responses to cholinergic activation in the MSA. In the present study, we investigated if the accumulation of endogenous H2O2 in the MSA after the injection of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ) also affects cholinergic responses. In addition, the effects of the combination of ATZ with a non-effective dose of H2O2 in the MSA were also tested. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The treatment with ATZ (10 nmol) into the MSA partially reverted the antidiuretic effect of carbachol (10.5 ± 0.7, vs. saline + carbachol: 7.3 ± 0.6 ml/120 min), without changing carbachol-induced water intake (9.5 ± 1.9, vs. saline + carbachol: 10.7 ± 1.6 ml/60 min). The combination of a low dose of ATZ (2.5 nmol) with an ineffective dose of H2O2 (0.5 μmol) into the MSA reduced carbachol-induced thirst (7.5 ± 2.0, vs. saline + carbachol: 14.9 ± 1.2 ml/15 min) and reverted the antidiuresis (8.1 ± 1.1, vs. saline + carbachol: 5.3 ± 0.9 ml/120 min). Sodium and potassium excretion were not modified regardless the treatment. Although exogenous H2O2 injected in the MSA may affect most of the responses to cholinergic activation of the MSA, the antidiuresis is the response clearly modulated by endogenous H2O2.
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Affiliation(s)
- Jéssica Matheus Sá
- Department of Physiology and Pathology, School of Dentistry, UNESP - São Paulo State University, Araraquara, SP, Brazil
| | - Milena Cassolatti Barros
- Department of Physiology and Pathology, School of Dentistry, UNESP - São Paulo State University, Araraquara, SP, Brazil
| | - Mariana Rosso Melo
- Department of Physiology and Pathology, School of Dentistry, UNESP - São Paulo State University, Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, UNESP - São Paulo State University, Araraquara, SP, Brazil
| | - José Vanderlei Menani
- Department of Physiology and Pathology, School of Dentistry, UNESP - São Paulo State University, Araraquara, SP, Brazil
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4
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Supplementation with zinc in rats enhances memory and reverses an age-dependent increase in plasma copper. Behav Brain Res 2017; 333:179-183. [PMID: 28693861 DOI: 10.1016/j.bbr.2017.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022]
Abstract
Zinc and copper are essential trace elements. Dyshomeostasis in these two metals has been observed in Alzheimer's disease, which causes profound cognitive impairment. Insulin therapy has been shown to enhance cognitive performance; however, recent data suggest that this effect may be at least in part due to the inclusion of zinc in the insulin formulation used. Zinc plays a key role in regulation of neuronal glutamate signaling, suggesting a possible link between zinc and memory processes. Consistent with this, zinc deficiency causes cognitive impairments in children. The effect of zinc supplementation on short- and long-term recognition memory, and on spatial working memory, was explored in young and adult male Sprague Dawley rats. After behavioral testing, hippocampal and plasma zinc and copper were measured. Age increased hippocampal zinc and copper, as well as plasma copper, and decreased plasma zinc. An interaction between age and treatment affecting plasma copper was also found, with zinc supplementation reversing elevated plasma copper concentration in adult rats. Zinc supplementation enhanced cognitive performance across tasks. These data support zinc as a plausible therapeutic intervention to ameliorate cognitive impairment in disorders characterized by alterations in zinc and copper, such as Alzheimer's disease.
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Aldana BI, Waagepetersen HS, Schousboe A, White HS, Bulaj G, Walls AB. The novel anticonvulsant neuropeptide and galanin analogue, NAX-5055, does not alter energy and amino acid metabolism in cultured brain cells. J Neurosci Res 2017; 95:2286-2296. [PMID: 28397993 DOI: 10.1002/jnr.24057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/08/2017] [Accepted: 03/05/2017] [Indexed: 11/09/2022]
Abstract
A large body of evidence suggests that the neuropeptide galanin plays an important role in seizure control. In line with this, it was demonstrated that the galanin analogue, NAX-5055, exerts a potent anticonvulsant activity in animal seizure models. We recently found that the NAX-5055-mediated anticonvulsant action involves modulation of both excitatory and inhibitory neurotransmission. Since homeostasis of neurotransmitters and cerebral energy metabolism are intimately linked, it was investigated whether the effects of NAX-5055 on neurotransmission involve changes in energy metabolism and in particular glucose- and amino acid metabolism. With this aim, cultured neurons from mouse brain were incubated with [U-13 C]glucose in absence or presence of NAX-5055. Since effects of NAX-5055 on neurotransmission were detected during repetitive stimulation, we tested potential metabolic effects while mimicking repetitive bursts of neurotransmitter release as occurring in the intact brain. The metabolic pathways were mapped using gas-chromatography coupled to mass-spectrometry. We found that NAX-5055 does not modify glucose metabolism in glutamatergic and GABAergic neurons. Furthermore, the effect of NAX-5055 on astrocyte-neuron metabolic interactions was investigated by incubating co-cultures of astrocytes and either glutamatergic or GABAergic neurons with [U-13 C]glucose or the glial-selective substrate [1,2-13 C]acetate, with or without NAX-5055. In the presence of NAX-5055, no changes in the metabolic landscape were traced. The findings suggest that the anticonvulsant action of NAX-5055 and the accompanying changes in neurotransmission do not involve alterations in energy and amino acid metabolism. Hence, NAX-5055 appears to be an anti-seizure drug candidate displaying no unwanted side effects concerning brain energy and amino acid homeostasis. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Steve White
- Anticonvulsant Drug Development Program, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA.,Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Grzegorz Bulaj
- University of Utah, Department of Medicinal Chemistry, College of Pharmacy, Salt Lake City, Utah, USA
| | - Anne B Walls
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Abstract
Since the neuropeptide galanin’s discovery in 1983, information has accumulated that implicates it in a wide range of functions, including pain sensation, stress responses, appetite regulation, and learning and memory. This article reviews the evidence for specific functions of galanin in cognitive processes. Consistencies as well as gaps in the literature are organized around basic questions of methodology and theory. This review shows that although regularities are evident in the observed behavioral effects of galanin across several methods for measuring learning and memory, generalization from these findings is tempered with concerns about confounds and a restricted range of testing conditions. Furthermore, it is revealed that many noncognitive behavioral constructs that are relevant for assessing potential roles for galanin in cognition have not been thoroughly examined. The review concludes by laying out how future theory and experimental work can overcome these concerns and confidently define the nature of the association of galanin with particular cognitive constructs.
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Malmevik J, Petri R, Knauff P, Brattås PL, Åkerblom M, Jakobsson J. Distinct cognitive effects and underlying transcriptome changes upon inhibition of individual miRNAs in hippocampal neurons. Sci Rep 2016; 6:19879. [PMID: 26813637 PMCID: PMC4728481 DOI: 10.1038/srep19879] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/21/2015] [Indexed: 11/09/2022] Open
Abstract
MicroRNAs (miRNA) are small, non-coding RNAs mediating post-transcriptional regulation of gene expression. miRNAs have recently been implicated in hippocampus-dependent functions such as learning and memory, although the roles of individual miRNAs in these processes remain largely unknown. Here, we achieved stable inhibition using AAV-delivered miRNA sponges of individual, highly expressed and brain-enriched miRNAs; miR-124, miR-9 and miR-34, in hippocampal neurons. Molecular and cognitive studies revealed a role for miR-124 in learning and memory. Inhibition of miR-124 resulted in an enhanced spatial learning and working memory capacity, potentially through altered levels of genes linked to synaptic plasticity and neuronal transmission. In contrast, inhibition of miR-9 or miR-34 led to a decreased capacity of spatial learning and of reference memory, respectively. On a molecular level, miR-9 inhibition resulted in altered expression of genes related to cell adhesion, endocytosis and cell death, while miR-34 inhibition caused transcriptome changes linked to neuroactive ligand-receptor transduction and cell communication. In summary, this study establishes distinct roles for individual miRNAs in hippocampal function.
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Affiliation(s)
- Josephine Malmevik
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
| | - Rebecca Petri
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
| | - Pina Knauff
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
| | - Per Ludvik Brattås
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
| | - Malin Åkerblom
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
| | - Johan Jakobsson
- Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, BMC A11, Lund University, Sölvegatan 17, 221 84 Lund, Sweden
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van der Zwaluw NL, van de Rest O, Kessels RPC, de Groot LCPGM. Effects of glucose load on cognitive functions in elderly people. Nutr Rev 2016; 73:92-105. [PMID: 26024496 DOI: 10.1093/nutrit/nuu002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glucose is the main fuel for the brain, and manipulation of the glucose supply may consequently affect brain function. The present review was conducted to provide an overview of studies that investigated the acute effects of glucose load on memory and other cognitive functions in elderly people. The effects of sucrose on cognition and suggested mechanisms were also explored. A total of twenty studies met the inclusion criteria. In the majority of studies, episodic memory was investigated and a beneficial role for glucose in that specific cognitive domain was suggested. Other cognitive domains, i.e., working memory, semantic memory, visual memory, information-processing speed, attention, executive function, and visual/spatial function, have been studied less frequently and evidence for a beneficial effect of glucose was equivocal. Mechanisms are suggested to be mainly related to the human body's need for glucose as a metabolic substrate for physiological mechanisms in both central and peripheral processes.
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Affiliation(s)
- Nikita L van der Zwaluw
- Affiliations: NL van der Zwaluw, O. van de Rest, and LCPGM de Groot are with the Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands. RPC Kessels is with the Department of Geriatrics, the Department of Medical Psychology, and Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. NikitavanderZwaluw@gmail
| | - Ondine van de Rest
- Affiliations: NL van der Zwaluw, O. van de Rest, and LCPGM de Groot are with the Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands. RPC Kessels is with the Department of Geriatrics, the Department of Medical Psychology, and Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Roy P C Kessels
- Affiliations: NL van der Zwaluw, O. van de Rest, and LCPGM de Groot are with the Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands. RPC Kessels is with the Department of Geriatrics, the Department of Medical Psychology, and Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Lisette C P G M de Groot
- Affiliations: NL van der Zwaluw, O. van de Rest, and LCPGM de Groot are with the Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands. RPC Kessels is with the Department of Geriatrics, the Department of Medical Psychology, and Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Abstract
Basal forebrain cholinergic neurons constitute a way station for many ascending and descending pathways. These cholinergic neurons have a role in eliciting cortical activation and arousal. It is well established that they are mainly involved in cognitive processes requiring increased levels of arousal, attentive states and/or cortical activation with desynchronized activity in the EEG. These cholinergic neurons are modulated by several afferents of different neurotransmitter systems. Of particular importance within the cortical targets of basal forebrain neurons is the hippocampal cortex. The septohippocampal pathway is a bidirectional pathway constituting the main septal efferent system, which is widely known to be implicated in every memory process investigated. The present work aims to review the main neurotransmitter systems involved in modulating cognitive processes related to learning and memory through modulation of basal forebrain neurons.
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Hydrogen peroxide attenuates the dipsogenic, renal and pressor responses induced by cholinergic activation of the medial septal area. Neuroscience 2014; 284:611-621. [PMID: 25453778 DOI: 10.1016/j.neuroscience.2014.10.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/22/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023]
Abstract
Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis, antidiuresis and pressor response. In the brain, hydrogen peroxide (H2O2) modulates autonomic and behavioral responses. In the present study, we investigated the effects of the combination of carbachol and H2O2 injected into the MSA on water intake, renal excretion, cardiovascular responses and the activity of vasopressinergic and oxytocinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. Furthermore, the possible modulation of carbachol responses by H2O2 acting through K+ATP channels was also investigated. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The pre-treatment with H2O2 in the MSA reduced carbachol-induced thirst (7.9±1.0, vs. carbachol: 13.2±2.0 ml/60 min), antidiuresis (9.6±0.5, vs. carbachol: 7.0±0.8 ml/120 min,), natriuresis (385±36, vs. carbachol: 528±46 μEq/120 min) and pressor response (33±5, vs. carbachol: 47±3 mmHg). Combining H2O2 and carbachol into the MSA also reduced the number of vasopressinergic neurons expressing c-Fos in the PVN (46.4±11.2, vs. carbachol: 98.5±5.9 c-Fos/AVP cells) and oxytocinergic neurons expressing c-Fos in the PVN (38.5±16.1, vs. carbachol: 75.1±8.5 c-Fos/OT cells) and in the SON (57.8±10.2, vs. carbachol: 102.7±7.4 c-Fos/OT cells). Glibenclamide (K+ATP channel blocker) into the MSA partially reversed H2O2 inhibitory responses. These results suggest that H2O2 acting through K+ATP channels in the MSA attenuates responses induced by cholinergic activation in the same area.
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Gold PE, Newman LA, Scavuzzo CJ, Korol DL. Modulation of multiple memory systems: from neurotransmitters to metabolic substrates. Hippocampus 2013; 23:1053-65. [PMID: 23929581 PMCID: PMC9676045 DOI: 10.1002/hipo.22182] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2013] [Indexed: 01/14/2023]
Abstract
This article reviews evidence showing that neurochemical modulators can regulate the relative participation of the hippocampus and striatum in learning and memory tasks. For example, relative release of acetylcholine increases in the hippocampus and striatum reflects the relative engagement of these brain systems during learning of place and response tasks. Acetylcholine release is regulated in part by available brain glucose levels, which themselves are dynamically modified during learning. Recent findings suggest that glucose acts through astrocytes to deliver lactate to neurons. Brain glycogen is contained in astrocytes and provides a capacity to deliver energy substrates to neurons when needed, a need that can be generated by training on tasks that target hippocampal and striatal processing mechanisms. These results integrate an increase in blood glucose after epinephrine release from the adrenal medulla with provision of brain energy substrates, including lactate released from astrocytes. Together, the availability of peripheral and central energy substrates regulate the processing of learning and memory within and across multiple neural systems. Dysfunctions of the physiological steps that modulate memory--from hormones to neurotransmitters to metabolic substrates--may contribute importantly to some of the cognitive impairments seen during normal aging and during neurodegenerative diseases.
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Affiliation(s)
- Paul E. Gold
- Department of Biology, Syracuse University, Syracuse, New York
| | - Lori A. Newman
- Department of Biology, Syracuse University, Syracuse, New York
| | - Claire J. Scavuzzo
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, Illinois
| | - Donna L. Korol
- Department of Biology, Syracuse University, Syracuse, New York
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Morris KA, Li S, Bui DD, Gold PE. Glucose attenuates impairments in memory and CREB activation produced by an α4β2 but not an α7 nicotinic receptor antagonist. Neuropharmacology 2013; 67:233-42. [PMID: 23164619 PMCID: PMC3562370 DOI: 10.1016/j.neuropharm.2012.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 10/30/2012] [Accepted: 11/04/2012] [Indexed: 12/24/2022]
Abstract
Glucose improves memory for a variety of tasks when administered to rats and mice near the time of training. Prior work indicates glucose may enhance memory by increasing the synthesis and release of the neurotransmitter acetylcholine in the brain. To investigate if specific acetylcholine receptor subtypes may mediate some of the memory-enhancing actions of glucose, we examined the effects of subtype-specific nicotinic acetylcholine receptor antagonists on memory in Fischer-344 rats and also examined the ability of glucose to reverse drug-induced impairments. Pre-training peripheral injections of methyllycaconitine (MLA) or dihydro-beta-erythroidine (DHβE), which are specific α7 and α4β2 nicotinic receptor antagonists, respectively, dose-dependently impaired retention latencies in an inhibitory avoidance task when tested 7-days but not 1 h after training. Immediate post-training glucose injections attenuated the impairments, but were more effective in attenuating the DHβE-induced impairments. Likewise, peripheral or direct intrahippocampal injections of MLA or DHβE dose-dependently impaired spatial working memory scores on a spontaneous alternation task. Concurrent administration of glucose reversed DHβE- but not MLA-induced impairments. CREB phosphorylation downstream of cholinergic signaling was assessed 30 min after spontaneous alternation testing and intrahippocampal drug infusions. Both MLA and DHβE impaired hippocampal CREB phosphorylation; glucose reversed DHβE- but not MLA-induced deficits. The effectiveness of glucose in reversing DHβE- but not MLA-induced impairments in behavioral performance and CREB phosphorylation suggests that activation of α7 receptors may play an important role in memory enhancement by glucose.
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Affiliation(s)
- Ken A. Morris
- Neuroscience Program and College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Sisi Li
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Duat D. Bui
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Paul E. Gold
- Department of Biology, Syracuse University, Syracuse, NY, United States
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Morris KA, Gold PE. Epinephrine and glucose modulate training-related CREB phosphorylation in old rats: relationships to age-related memory impairments. Exp Gerontol 2013; 48:115-27. [PMID: 23201424 PMCID: PMC3557608 DOI: 10.1016/j.exger.2012.11.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 11/04/2012] [Accepted: 11/21/2012] [Indexed: 12/21/2022]
Abstract
Epinephrine enhances memory in young adult rats, in part, by increasing blood glucose levels needed to modulate memory. In old rats, epinephrine is deficient at raising blood glucose levels and thus is only moderately effective at enhancing memory. In contrast, systemic glucose injections improve memory in old rats, with resulting memory performance equal to that of young rats. The diminished response of glucose to training in old rats may blunt downstream neurochemical and molecular mechanisms needed to upregulate memory processes. In the first experiment, young adult and old rats were trained on an inhibitory avoidance task with immediate post-training injections of aCSF or glucose into the dorsal hippocampus. Old rats had significant memory impairments compared to young rats 7 days after training. Intrahippocampal injections of glucose reversed age-related deficits, improving memory scores in old rats to values seen in young rats. A second experiment examined age-related changes in activation of the transcription factor CREB, which is widely implicated in memory formation and may act downstream of hormonal and metabolic signals. Activation was assessed in response to training with systemic injections of epinephrine and glucose at doses known to enhance memory. Young adult and old rats were trained on inhibitory avoidance with immediate post-training systemic injections of saline, epinephrine, or glucose. After training, old rats had significant impairments in CREB phosphorylation in area CA1 and the dentate gyrus region of the hippocampus, and in the basolateral and lateral amygdala. Epinephrine and glucose attenuated age-related deficits in CREB phosphorylation, but were more effective in the amygdala and hippocampus, respectively. Together, these results support the view that age-related changes in blood glucose responses to epinephrine contribute to memory impairments, which may be related to alterations in regional patterns of CREB phosphorylation.
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Affiliation(s)
- Ken A. Morris
- Neuroscience Program and College of Medicine, University of Illinois at Urbana-Champaign IL 61801
| | - Paul E. Gold
- Department of Biology, Life Sciences Complex, Syracuse University, Syracuse, NY 13244
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Callander GE, Ma S, Ganella DE, Wimmer VC, Gundlach AL, Thomas WG, Bathgate RAD. Silencing relaxin-3 in nucleus incertus of adult rodents: a viral vector-based approach to investigate neuropeptide function. PLoS One 2012; 7:e42300. [PMID: 22876314 PMCID: PMC3410922 DOI: 10.1371/journal.pone.0042300] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 07/05/2012] [Indexed: 11/18/2022] Open
Abstract
Relaxin-3, the most recently identified member of the relaxin peptide family, is produced by GABAergic projection neurons in the nucleus incertus (NI), in the pontine periventricular gray. Previous studies suggest relaxin-3 is a modulator of stress responses, metabolism, arousal and behavioural activation. Knockout mice and peptide infusions in vivo have significantly contributed to understanding the function of this conserved neuropeptide. Yet, a definitive role remains elusive due to discrepancies between models and a propensity to investigate pharmacological effects over endogenous function. To investigate the endogenous function of relaxin-3, we generated a recombinant adeno-associated viral (rAAV) vector expressing microRNA against relaxin-3 and validated its use to knock down relaxin-3 in adult rats. Bilateral stereotaxic infusion of rAAV1/2 EmGFP miR499 into the NI resulted in significant reductions in relaxin-3 expression as demonstrated by ablation of relaxin-3-like immunoreactivity at 3, 6 and 9 weeks and by qRT-PCR at 12 weeks. Neuronal health was unaffected as transduced neurons in all groups retained expression of NeuN and stained for Nissl bodies. Importantly, qRT-PCR confirmed that relaxin-3 receptor expression levels were not altered to compensate for reduced relaxin-3. Behavioural experiments confirmed no detrimental effects on general health or well-being and therefore several behavioural modalities previously associated with relaxin-3 function were investigated. The validation of this viral vector-based model provides a valuable alternative to existing in vivo approaches and promotes a shift towards more physiologically relevant investigations of endogenous neuropeptide function.
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Affiliation(s)
- Gabrielle E. Callander
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
- * E-mail: (GEC); (RADB)
| | - Sherie Ma
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
- Department of Medicine (Austin Health), The University of Melbourne, Victoria, Australia
| | - Despina E. Ganella
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
| | - Verena C. Wimmer
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
| | - Andrew L. Gundlach
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria, Australia
| | - Walter G. Thomas
- School of Biomedical Sciences, University of Queensland, Queensland, Australia
| | - Ross A. D. Bathgate
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Victoria, Australia
- Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia
- * E-mail: (GEC); (RADB)
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15
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Parent MB, Krebs-Kraft DL, Ryan JP, Wilson JS, Harenski C, Hamann S. Glucose administration enhances fMRI brain activation and connectivity related to episodic memory encoding for neutral and emotional stimuli. Neuropsychologia 2011; 49:1052-1066. [DOI: 10.1016/j.neuropsychologia.2011.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 10/18/2022]
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16
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17
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Galanin impairs cognitive abilities in rodents: relevance to Alzheimer's disease. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:133-41. [PMID: 21299066 DOI: 10.1007/978-3-0346-0228-0_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The neuropeptide galanin and its receptors are localized in brain pathways that mediate learning and memory. Central microinjection of galanin impairs performance of a variety of cognitive tasks in rats. Transgenic mice overexpressing galanin display deficits in some learning and memory tests. The inhibitory role of galanin in cognitive processes, taken together with the fact that overexpression of galanin occurs in Alzheimer's disease, suggests that galanin antagonists may offer a novel therapeutic approach to treat memory loss in patients suffering from Alzheimer's.
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Krebs-Kraft DL, Parent MB. Septal co-infusions of glucose with the benzodiazepine agonist chlordiazepoxide impair memory, but co-infusions of glucose with the opiate morphine do not. Physiol Behav 2009; 99:438-44. [PMID: 20005883 DOI: 10.1016/j.physbeh.2009.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 11/24/2009] [Accepted: 12/04/2009] [Indexed: 10/20/2022]
Abstract
We have found repeatedly that medial septal (MS) infusions of glucose impair memory when co-infused with the gamma-amino butyric acid (GABA) agonist muscimol. The present experiments sought to determine whether the memory-impairing effects of this concentration of glucose would generalize to another GABA(A) receptor agonist and to an agonist from another neurotransmitter system that is known to impair memory. Specifically, we determined whether the dose of glucose that produces memory deficits when combined with muscimol in the MS would also impair memory when co-infused with the GABA(A) receptor modulator chlordiazepoxide (CDP) or the opiate morphine. Male Sprague-Dawley rats were given MS co-infusions and then 15 min later tested for spontaneous alternation or given shock avoidance training (retention tested 48 h later). The results showed that MS infusions of the higher dose of glucose with morphine did not produce memory deficits, whereas, the performance of rats given MS co-infusions of CDP with glucose was impaired. These findings suggest that the memory-impairing effects of brain glucose administration may involve an interaction with the GABA(A) receptor.
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Affiliation(s)
- Desiree L Krebs-Kraft
- Department of Psychology and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA.
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19
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Modulation of hippocampal theta oscillations and spatial memory by relaxin-3 neurons of the nucleus incertus. Learn Mem 2009; 16:730-42. [PMID: 19880588 DOI: 10.1101/lm.1438109] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that "pacemaker" neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the neuropeptide relaxin-3 (RLN3). Therefore, this study examined the possible contribution of RLN3 to MS activity, and associated hippocampal theta activity and spatial memory. In anesthetized and conscious rats, we identified the ability of intraseptal RLN3 signaling to modulate neuronal activity in the MS and hippocampus and promote hippocampal theta rhythm. Behavioral studies in a spontaneous alternation task indicated that endogenous RLN3 signaling within MS promoted spatial memory and exploratory activity significantly increased c-Fos immunoreactivity in RLN3-producing NI neurons. Anatomical studies demonstrated axons/terminals from NI/RLN3 neurons make close contact with septal GABAergic (and cholinergic) neurons, including those that project to the hippocampus. In summary, RLN3 neurons of the NI can modulate spatial memory and underlying hippocampal theta activity through axonal projections to pacemaker neurons of the MS. NI/RLN3 neurons are highly responsive to stress and express corticotropin-releasing factor type-1 receptors, suggesting that the effects observed could be an important component of memory processing associated with stress responses.
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20
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Krebs-Kraft DL, Rauw G, Baker GB, Parent MB. Zero net flux estimates of septal extracellular glucose levels and the effects of glucose on septal extracellular GABA levels. Eur J Pharmacol 2009; 611:44-52. [PMID: 19345207 PMCID: PMC2866298 DOI: 10.1016/j.ejphar.2009.03.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/17/2009] [Accepted: 03/23/2009] [Indexed: 11/21/2022]
Abstract
Although hippocampal infusions of glucose enhance memory, we have found repeatedly that septal glucose infusions impair memory when gamma-aminobutyric acid (GABA) receptors are activated. For instance, hippocampal glucose infusions reverse the memory-impairing effects of co-infusions of the GABA agonist muscimol, whereas septal glucose infusions exacerbate memory deficits produced by muscimol. One potential explanation for these deleterious effects of glucose in the septum is that there are higher levels of endogenous extracellular fluid glucose concentrations in the septum than in the hippocampus. Another hypothesis is that septal glucose infusions impair memory by increasing septal GABA synthesis or release, which is possible because elevating glucose increases GABA levels in other brain regions. To test these hypotheses, Experiment 1 quantified extracellular fluid glucose levels in the septum and hippocampus using zero net flux in vivo microdialysis procedures in conscious, freely moving rats. Experiment 2 determined whether septal infusions of glucose would increase GABA concentrations in dialysates obtained from the septum. The results of Experiment 1 indicated that extracellular fluid glucose levels in the hippocampus and septum are comparable. The results of Experiment 2 showed that co-infusions of glucose with muscimol, at doses that did not affect memory on their own, decreased percent alternation memory scores. However, none of the infusions significantly affected GABA levels. Collectively, these findings suggest that the memory-impairing effects of septal infusions of glucose are not likely due to regional differences in basal extracellular fluid glucose concentrations and are not mediated via an increase in septal GABA release.
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Qi Z, Gold PE. Intrahippocampal infusions of anisomycin produce amnesia: contribution of increased release of norepinephrine, dopamine, and acetylcholine. Learn Mem 2009; 16:308-14. [PMID: 19403793 DOI: 10.1101/lm.1333409] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Intra-amygdala injections of anisomycin produce large increases in the release of norepinephrine (NE), dopamine (DA), and serotonin in the amygdala. Pretreatment with intra-amygdala injections of the beta-adrenergic receptor antagonist propranolol attenuates anisomycin-induced amnesia without reversing the inhibition of protein synthesis, and injections of NE alone produce amnesia. These findings suggest that abnormal neurotransmitter responses may be the basis for amnesia produced by inhibition of protein synthesis. The present experiment extends these findings to the hippocampus and adds acetylcholine (ACh) to the list of neurotransmitters affected by anisomycin. Using in vivo microdialysis at the site of injection, release of NE, DA, and ACh was measured before and after injections of anisomycin into the hippocampus. Anisomycin impaired inhibitory avoidance memory when rats were tested 48 h after training and also produced substantial increases in local release of NE, DA, and ACh. In an additional experiment, pretreatment with intrahippocampal injections of propranolol prior to anisomycin and training significantly attenuated anisomycin-induced amnesia. The disruption of neurotransmitter release patterns at the site of injection appears to contribute significantly to the mechanisms underlying amnesia produced by protein synthesis inhibitors, calling into question the dominant interpretation that the amnesia reflects loss of training-initiated protein synthesis necessary for memory formation. Instead, the findings suggest that proteins needed for memory formation are available prior to an experience, and that post-translational modifications of these proteins may be sufficient to enable the formation of new memories.
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Affiliation(s)
- Zhenghan Qi
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, Illinois 61820, USA
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22
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Abstract
The neuropeptide galanin and its receptors are localized in brain pathways mediating learning and memory. Central microinjection of galanin impairs performance of a variety of cognitive tasks in rats. Transgenic mice overexpressing galanin display deficits in some learning and memory tests. The inhibitory role of galanin in cognitive processes, taken together with the overexpression of galanin in Alzheimer's disease, suggests that galanin antagonists may offer a novel therapeutic approach to treat memory loss in Alzheimer's patients.
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Affiliation(s)
- J N Crawley
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Porter Neuroscience Research, Center Building 35, Room 1C-903, Mail Code 3730, Bethesda, Maryland 20892-3730, USA.
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23
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Stone WS, Seidman LJ. Toward a model of memory enhancement in schizophrenia: glucose administration and hippocampal function. Schizophr Bull 2008; 34:93-108. [PMID: 17504777 PMCID: PMC2632374 DOI: 10.1093/schbul/sbm041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Recognition of the need to treat cognitive deficits in schizophrenia is compelling and well established, with empirical findings and conceptual arguments related to cognitive enhancement appearing regularly in the literature. Cognitive enhancement itself, however, remains at an early stage. Biological approaches have centered on the development of antipsychotic medications that also improve cognition, but the results have so far remained modest. As a way to facilitate the development of cognitive enhancers in schizophrenia, this article focuses on adjunctive pharmacological approaches to antipsychotic medications and highlights the need for systematic explorations of relevant brain mechanisms. While numerous conceptual criteria might be employed to guide the search, we will focus on 4 points that are especially likely to be useful and which have not yet been considered together. First, the discussion will focus on deficits in a particular cognitive domain, verbal declarative memory. Second, we will review the current status of preclinical and clinical efforts to improve declarative memory using antipsychotic medications, which is the main, existing mode of treatment. Third, we will examine an example of an adjunctive intervention-glucose administration-that improves memory in animals and humans, modulates function in brain regions related to verbal declarative memory, and is highly amenable to translational research. Finally, a heuristic model will be outlined to explore how the intervention maps on to the underlying neurobiology of schizophrenia. More generally, the discussion underlines the promise of cognitive improvement in schizophrenia and the need to approach the issue in a programmatic manner.
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Affiliation(s)
- William S Stone
- Department of Psychiatry, Harvard Medical School, Boston, MA 02114, USA.
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Moazedi A, Belaran M, Hemmaty A, Rasekh A. The Role of Beta-Adrenergic System on the Enhancement of Spatial Learning Caused by Glucose Injection in Young Male Rats. INT J PHARMACOL 2007. [DOI: 10.3923/ijp.2008.34.39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Moazedi A, Belaran M, Hemmaty A, Rasekh A. Co-Administration of Epinephrine and Glucose Do Not Have Synergic Effects on the Improvement of Spatial Learning Task in Young Male Rats. JOURNAL OF MEDICAL SCIENCES 2007. [DOI: 10.3923/jms.2008.22.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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26
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McNay EC, Gold PE. Food for thought: fluctuations in brain extracellular glucose provide insight into the mechanisms of memory modulation. ACTA ACUST UNITED AC 2007; 1:264-80. [PMID: 17712984 DOI: 10.1177/1534582302238337] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Extensive evidence indicates that peripheral or direct central glucose administration enhances cognitive processes in rodents and humans. These behavioral findings suggest that glucose acts directly on the brain to regulate neural processing, a function that seems incompatible with the traditional view that brain glucose levels are high and invariant except under extreme conditions. However, recent data suggest that the glucose levels of the brain's extracellular fluid are lower and more variable than previously supposed. In particular, the level of glucose in the extracellular fluid of a given brain area decreases substantially when a rat is performing a memory task for which the brain area is necessary. Together with results identifying downstream effects of such variance in glucose availability, the evidence leads to new thinking about glucose regulation of brain functions including memory.
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27
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Krebs-Kraft DL, Parent MB. Hippocampal infusions of glucose reverse memory deficits produced by co-infusions of a GABA receptor agonist. Neurobiol Learn Mem 2007; 89:142-52. [PMID: 17728160 PMCID: PMC2259438 DOI: 10.1016/j.nlm.2007.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 07/11/2007] [Accepted: 07/15/2007] [Indexed: 11/30/2022]
Abstract
Although septal infusions of glucose typically have positive effects on memory, we have shown repeatedly that this treatment exacerbates memory deficits produced by co-infusions of gamma-aminobutyric acid (GABA) receptor agonists. The present experiments tested whether this negative interaction between glucose and GABA in the medial septum would be observed in the hippocampus, a brain region where glucose typically has positive effects on memory. Specifically, we determined whether hippocampal infusions of glucose would reverse or exacerbate memory deficits produced by hippocampal co-infusions of the GABA receptor agonist muscimol. Fifteen minutes prior to either assessing spontaneous alternation (SA) or continuous multiple trial inhibitory avoidance (CMIA) training, male Sprague-Dawley-derived rats were given bilateral hippocampal infusions of vehicle (phosphate-buffered saline [PBS], 1 microl/2 min), glucose (33 or 50 nmol), muscimol (0.3 or 0.4 microg, SA or 3 microg, CMIA) or muscimol and glucose combined in one solution. The results indicated that hippocampal infusions of muscimol alone decreased SA scores and CMIA retention latencies. More importantly, hippocampal infusions of glucose, at doses that had no effect when infused alone, attenuated (33 nmol) or reversed (50 nmol) the muscimol-induced memory deficits. Thus, although co-infusions of glucose with muscimol into the medial septum impair memory, the present findings show that an opposite effect is observed in the hippocampus. Collectively, these findings suggest that the memory-impairing interaction between glucose and GABA in the medial septum is not a general property of the brain, but rather is brain region-dependent.
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Affiliation(s)
- Desiree L Krebs-Kraft
- Department of Psychology and Center for Behavioral Neuroscience, Georgia State University, P.O. Box 5010, Atlanta, GA 30302-5010, USA.
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28
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Chang Q, Gold PE. Age-related changes in memory and in acetylcholine functions in the hippocampus in the Ts65Dn mouse, a model of Down syndrome. Neurobiol Learn Mem 2007; 89:167-77. [PMID: 17644430 PMCID: PMC2246382 DOI: 10.1016/j.nlm.2007.05.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 05/29/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022]
Abstract
Spatial working memory and the ability of a cholinesterase inhibitor to enhance memory were assessed at 4, 10, and 16 months of ages in control and Ts65Dn mice, a partial trisomy model of Down syndrome, with possibly significant relationships to Alzheimer's disease as well. In addition, ACh release during memory testing was measured in samples collected from the hippocampus using in vivo microdialysis at 4, 10, and 22-25 months of age. When tested on a four-arm spontaneous alternation task, the Ts65Dn mice exhibited impaired memory scores at both 4 and 10 months. At 16 months, control performance had declined toward that of the Ts65Dn mice and the difference in scores across genotypes was not significant. Physostigmine (50 microg/kg) fully reversed memory deficits in the Ts65Dn mice in the 4-month-old group but not in older mice. Ts65Dn and control mice exhibited comparable baseline levels of ACh release at all ages tested; these levels did not decline significantly across age in either genotype. ACh release increased significantly during alternation testing only in the young Ts65Dn and control mice. However, the increase in ACh release during alternation testing was significantly greater in control than Ts65Dn mice at this age. The controls exhibited a significant age-related decline in the testing-related increase in ACh release. With only a small increase during testing in young Ts65Dn mice, the age-related decline in responsiveness of ACh release to testing was not significant in these mice. Overall, these results suggest that diminished responsiveness of ACh release in the hippocampus to behavioral testing may contribute memory impairments in Ts65Dn mice.
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Affiliation(s)
- Qing Chang
- Department of Psychology, Neuroscience Program, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
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29
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Korol D, Gold P. Epinephrine converts long-term potentiation from transient to durable form in awake rats. Hippocampus 2007; 18:81-91. [DOI: 10.1002/hipo.20372] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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Choeiri C, Staines WA, Miki T, Seino S, Renaud JM, Teutenberg K, Messier C. Cerebral glucose transporters expression and spatial learning in the K-ATP Kir6.2(-/-) knockout mice. Behav Brain Res 2006; 172:233-9. [PMID: 16797737 DOI: 10.1016/j.bbr.2006.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 04/28/2006] [Accepted: 05/04/2006] [Indexed: 11/15/2022]
Abstract
K-ATP channels formed of the Sur and Kir subunits are widely distributed in the brain. Sur1-Kir6.2 is the most common combination of K-ATP channel subunits in the brain and Kir6.2 plays an important role in glucose metabolism through pancreatic insulin secretion or hypothalamic glucose sensing. K-ATP channels have also been reported to play a role in memory processing. Therefore, the aim of the present experiment is to assess the gene and protein expression of GLUT1, GLUT3 and GLUT4 in various brain regions of Kir6.2(-/-) K-ATP knockout mice and to test their working memory performance. GLUT4 was measured using two antibodies, one recognizing an intracellular epitope and the other, an extracellular epitope. Relative to their corresponding wild type, semi-quantitative immunohistochemistry showed that GLUT4 protein expression as measured by a GLUT4 antibody recognizing an extracellular epitope was increased in the Kir6.2(-/-) K-ATP mice. However, there was only a small increase in GLUT4 labeling using the GLUT4 antibody recognizing the intracellular epitope. These results suggest a compensatory higher GLUT4 inclusion at the cellular neuronal membrane in the cerebral cortex, hippocampus and cerebellum of the Kir6.2(-/-) K-ATP knockout mice. However, there was no change in GLUT4 gene expression assessed by TaqMan PCR except for a decrease in the cerebellum of these mice. Working memory performance of the Kir6.2(-/-) K-ATP mice was disrupted at age of 12 weeks but not at 5 weeks. The mild glucose intolerance that is observed in the Kir6.2 knockout mice is unlikely to have created the memory deficits observed. Rather, in light of the effects of K-ATP channel modulators on memory, the memory deficits in the Kir6.2(-/-) K-ATP mice are more likely due to the absence of the Kir6.2 and possible disruption of the GLUT4 activity in the brain.
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Affiliation(s)
- C Choeiri
- Psychology Faculty, Fresno Pacific University, 1717 South Chestnut Ave. Fresno, CA 93702, USA
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31
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Krebs DL, Parent MB. Hippocampal infusions of pyruvate reverse the memory-impairing effects of septal muscimol infusions. Eur J Pharmacol 2006; 520:91-9. [PMID: 16150437 PMCID: PMC1668712 DOI: 10.1016/j.ejphar.2005.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 08/05/2005] [Indexed: 10/25/2022]
Abstract
Hippocampal infusions of glucose reverse memory deficits in spontaneous alternation and in a continuous multiple trial inhibitory avoidance task. The current experiments tested whether glucose metabolism may participate in these effects of glucose. Specifically, these experiments determined whether the glycolytic metabolite pyruvate would mimic these effects of glucose. Male Sprague-Dawley rats were given septal infusions of vehicle or the gamma-aminobutyric acid (GABA) receptor agonist muscimol (0.15 nmol for spontaneous alternation or 5 nmol for continuous multiple trial inhibitory avoidance) combined with hippocampal infusions of vehicle or pyruvate (200 nmol) 15 min prior to assessing spontaneous alternation or training in a continuous multiple trial inhibitory avoidance task. The infusions of muscimol decreased percent alternation scores and continuous multiple trial inhibitory avoidance retention latencies tested 48 h after training. More importantly, hippocampal infusions of pyruvate reversed the deficits produced by septal infusions of muscimol on both tasks. These findings show for the first time that hippocampal infusions of pyruvate influence memory and suggest that glucose may affect memory via glycolytic metabolism.
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Affiliation(s)
- Desiree L. Krebs
- * Corresponding author. Tel.: +1 404 651 1755 (Lab), +1 404 651 3108 (Office); fax: +1 404 651 3929. E-mail address: (D.L. Krebs)
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32
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Erickson EJ, Watts KD, Parent MB. Septal co-infusions of glucose with a GABAB agonist impair memory. Neurobiol Learn Mem 2006; 85:66-70. [PMID: 16226043 PMCID: PMC1776567 DOI: 10.1016/j.nlm.2005.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 08/17/2005] [Accepted: 08/18/2005] [Indexed: 11/25/2022]
Abstract
Septal infusions of glucose exacerbate memory deficits produced by co-infusions of drugs that increase gamma-aminobutyric acid (GABA)(A) receptor activity. To further understand the interaction between glucose and GABA, this experiment tested whether glucose would also potentiate spatial working memory deficits produced by septal infusions of the GABA(B) receptor agonist baclofen. Fifteen minutes prior to assessing spontaneous alternation (SA), male Sprague-Dawley derived rats were given septal infusions of vehicle, glucose (33 nmol), baclofen (0.1 nmol), or glucose combined with baclofen in one solution. Septal co-infusions of glucose with baclofen, at doses that individually had no effect, significantly impaired SA. Thus, the memory-impairing effects of glucose are observed with either GABA(A) or GABA(B) receptor ligands. This raises the possibility that glucose may impair memory by increasing synaptic levels of GABA and subsequent activation of these different receptor subtypes. These effects of glucose could contribute to the memory-impairing effects of hyperglycemia.
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Affiliation(s)
- Erika J. Erickson
- Department of Psychology, Georgia State University, P.O. Box 5010, Atlanta, GA 30302-5010, USA
- Center for Behavioral Neuroscience, Georgia State University, P.O. Box 3966, Atlanta, GA 30302-3966, USA
| | - Kelly D. Watts
- Center for Behavioral Neuroscience, Georgia State University, P.O. Box 3966, Atlanta, GA 30302-3966, USA
- Emory University Neuroscience Program, 105-E North Jamestown Road, Decatur GA 30033, USA
| | - Marise B. Parent
- Department of Psychology, Georgia State University, P.O. Box 5010, Atlanta, GA 30302-5010, USA
- Center for Behavioral Neuroscience, Georgia State University, P.O. Box 3966, Atlanta, GA 30302-3966, USA
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33
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Abstract
Epinephrine, released from the adrenal medulla, enhances memory in young rats and mice and apparently does so, at least in part, by increasing blood glucose levels. Like epinephrine, administration of glucose enhances cognitive functions in humans and rodents, including reversing age-related impairments in learning and memory. Epinephrine responses to training are increased in aged rats but the subsequent increase in blood glucose levels is severely blunted. The absence of increases in blood glucose levels during training might contribute to age-related deficits in learning and memory. Also, extracellular glucose levels in the hippocampus are depleted during spontaneous alternation testing to a far greater extent in aged than in young rats. Importantly, systemic injections of glucose block the depletion in the hippocampus and also enhance performance on the alternation task. Thus, the extensive depletion of extracellular glucose during training in aged rats may be associated with age-related memory impairments, an effect that might be related to - or may exacerbate - the effects on learning and memory of an absence of the increases in blood glucose levels to training as seen in young rats. Together, these findings suggest that age-related changes in both peripheral and central glucose physiology contribute to age-related impairments in memory.
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Affiliation(s)
- Paul E Gold
- Neuroscience Program and Departments of Psychology and Psychiatry, University of Illinois at Urbana-Champaign, 603 East Daniel Street, Champaign, IL 61820, USA.
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34
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Canal CE, Stutz SJ, Gold PE. Glucose injections into the dorsal hippocampus or dorsolateral striatum of rats prior to T-maze training: modulation of learning rates and strategy selection. Learn Mem 2005; 12:367-74. [PMID: 16027177 PMCID: PMC1183254 DOI: 10.1101/lm.88205] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The present experiments examined the effects of injecting glucose into the dorsal hippocampus or dorsolateral striatum on learning rates and on strategy selection in rats trained on a T-maze that can be solved by using either a hippocampus-sensitive place or striatum-sensitive response strategy. Percentage strategy selection on a probe trial (P(crit)) administered after rats achieved criterion (nine of 10 correct choices) varied by group. All groups predominately exhibited a response strategy on a probe trial administered after overtraining, i.e., after 90 trials. In experiment 1, rats that received intrahippocampal glucose injections showed enhanced acquisition of the T-maze and showed increased use of response solutions at P(crit) compared with that of unimplanted and artificial cerebral spinal fluid (aCSF)-treated groups. These findings suggest that glucose enhanced hippocampal functions to accelerate the rate of learning and the early adoption of a response strategy. In experiment 2, rats that received intrastriatal glucose injections exhibited place solutions early in training and reached criterion more slowly than did aCSF controls, with learning rates comparable to those of unoperated and operated-uninjected controls. Relative to unoperated, operated-uninjected and glucose-injected rats, rats that received intrastriatal aCSF injections showed enhanced acquisition of the T-maze and increased use of response solutions at P(crit). The unexpected enhanced acquisition seen after striatal aCSF injections suggests at least two possible interpretations: (1) aCSF impaired striatal function, thereby releasing competition with the hippocampus and ceding control over learning to the hippocampus during early training trials; and (2) aCSF enhanced striatal functioning to facilitate striatal-sensitive learning. With either interpretation, the results indicate that intrastriatal glucose injections compensated for the aCSF-induced effect. Finally, enhanced acquisition regardless of treatment was accompanied by rapid adoption of a response solution for the T-maze.
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Affiliation(s)
- Clinton E Canal
- The Neuroscience Program,University of Illinois, Urbana-Champaign, IL 61820, USA
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35
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Echevarria DJ, Brewer A, Bushell G, Manuzon H, Langel U, Robinson JK. Galanin and perseveration. Brain Res 2005; 1041:143-8. [PMID: 15829223 DOI: 10.1016/j.brainres.2005.01.103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 12/20/2004] [Accepted: 01/24/2005] [Indexed: 11/28/2022]
Abstract
Galanin is a 29/30 amino acid neuropeptide that has been shown to impair learning and memory task performance and also have roles in somatosensation, stress responses, sexual behavior, and feeding regulation. However, little is known about galanin involvement in higher cognitive processes, especially executive processes. Perseveration is a classic sign of frontal cortex damage and failure of executive control. Galanin has been shown to disrupt the performance of maze delayed alternation tasks and the operant, spatial delayed nonmatch-to-position (DNMTP) working memory task, tests especially sensitive to perseverative responding. To better understand this potential involvement of galanin in executive control, the present study tested the hypothesis that galanin induces perseveration. The first experiment examined the effects of galanin (10, 20 microg i.c.v.) on the performance of a simple operant response alternation task in which stimuli were assigned to one of two spatially distinct locations to produce extended sequences of presentations to one location, separated by a 10-s intertrial interval. The second experiment looked at the effects of galanin (5, 20 microg i.c.v.) on the performance of non-delayed match-to-position and nonmatch-to-position conditional discrimination operant tasks in which a minimal 1.0 s time interval separated responses. Finally, the effects of galanin (10, 20 microg i.c.v.) on delayed match-to-position (DMTP) performance were examined to determine whether response alternation (i.e., nonmatching) was critical to observing a galanin-induced impairment in this task. Galanin reduced the rate of trial completion in all the tasks, but did not alter simple or conditional discrimination accuracy. Galanin (10 microg) impaired DMTP performance in a delay-independent manner. Together, these data suggest that galanin does not produce perseveration, but are consistent with a galanin-induced decrease in reinforcer strength.
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Affiliation(s)
- David J Echevarria
- Department of Psychology, Stony Brook University, Biopsychology Program Area, Stony Brook, NY 11794-2500, USA
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Gold PE. Coordination of multiple memory systems. Neurobiol Learn Mem 2005; 82:230-42. [PMID: 15464406 DOI: 10.1016/j.nlm.2004.07.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 07/08/2004] [Accepted: 07/14/2004] [Indexed: 11/17/2022]
Abstract
On the basis of lesions of different brain areas, several neural systems appear to be important for processing information regarding different types of learning and memory. This paper examines the development of pharmacological and neurochemical approaches to multiple memory systems from past studies of modulation of memory formation. The findings suggest that peripheral neuroendocrine mechanisms that regulate memory processing may target their actions toward those neural systems most engaged in the processing of learning and memory. In addition, measurements of acetylcholine release in different memory systems reveals extensive interactions between memory systems, some cooperative and some competitive. These results imply that many neural systems, often characterized as relatively independent, may in fact interact extensively, blurring the dependencies of different memory tasks on specific neural systems.
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Affiliation(s)
- Paul E Gold
- Departments of Psychology and Psychiatry, Neuroscience Program and the Initiative on Aging, University of Illinois, Urbana-Champaign, IL 61820, USA.
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Diergaarde L, Gerrits MAFM, Brouwers JPW, van Ree JM. Early amygdala damage disrupts performance on medial prefrontal cortex-related tasks but spares spatial learning and memory in the rat. Neuroscience 2005; 130:581-90. [PMID: 15590142 DOI: 10.1016/j.neuroscience.2004.09.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2004] [Indexed: 11/25/2022]
Abstract
Recent studies have demonstrated that the postnatal development of connections between the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) mature around postnatal days 13-15 (pd13-15), whereas these between the BLA and other structures such as the nucleus accumbens and the mediodorsal thalamus are completed by pd7. Accordingly, it is hypothesized that mPFC cytoarchitecture and hence its function may be specifically affected by neonatal (i.e. on pd7) but not later induced (i.e. on pd21) damage to the BLA. To test this hypothesis, rats received excitotoxic lesions to the BLA on either pd7 or pd21 and were subjected to two tests putatively sensitive to mPFC dysfunction, namely food hoarding and spontaneous alternation. In addition, rats were tested for spatial learning and memory, to determine any possible effects on hippocampal function. Consistent with the documented effects of mPFC lesions, pd7 damage to the BLA impaired spontaneous alternation and food hoarding performance, an effect that was not found in rats with BLA lesions induced on pd21. Spatial learning and memory, however, were not affected by the (neonatal) lesion procedure. Together, these results indicate that neonatal BLA damage affects species-specific sequential behavior and flexibility, which may be attributed to abnormal functioning of the mPFC.
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Affiliation(s)
- L Diergaarde
- Rudolf Magnus Institute of Neuroscience, Department of Pharmacology and Anatomy, University Medical Center Utrecht, P.O. Box 80040, 3508 TA Utrecht, The Netherlands.
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Brewer A, Langel U, Robinson JK. Intracerebroventricularly administered galanin does not alter operant reaction time or differentially reinforced high rate schedule operant responding in rats. Neurosci Lett 2004; 369:245-9. [PMID: 15464273 DOI: 10.1016/j.neulet.2004.07.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 07/22/2004] [Accepted: 07/28/2004] [Indexed: 11/25/2022]
Abstract
Galanin (Gal) is a 29/30 amino acid neuroendocrine peptide that impairs learning and memory processes, stimulates feeding, and modulates somatosensory, sex, and stress responses. Anatomical markers for Gal are found throughout the brain, including in the caudate-putamen and substantia nigra motor regions. Many of the behavioral tests that have been used to study the involvement of Gal in complex behavioral processes are motorically demanding, but no research has specifically investigated the involvement of Gal in response initiation or the maintenance of fine motor action. Therefore, the present study examined the effects of intraventricularly administered Gal on two highly sensitive operant tasks designed to detect alteration of these response properties. Response initiation was studied using a light-dark discrimination reaction time task that required a correct response within 2.5s of a spatially and temporally uncertain stimulus onset. The ability to perform high local rates of responding was studied using an operant differential reinforcement of high rate (DRH) of responding task. Gal (10-20 microg, i.c.v.) did not alter reaction time or inter-response time distributions in either task, though did substantially reduce the total number of responses and reinforcers obtained on the DRH schedule. These results are consistent with a Gal-induced reduction of reinforcer efficacy rather than Gal-disruption of response initiation or response patterning.
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Affiliation(s)
- Ariel Brewer
- Department of Psychology, Biopsychology Program Area, Stony Brook University, Stony Brook, NY 11794-2500, USA
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Naftalin RJ, Cunningham P, Afzal-Ahmed I. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport. Br J Pharmacol 2004; 142:594-608. [PMID: 15148255 PMCID: PMC1574967 DOI: 10.1038/sj.bjp.0705798] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1 Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. 2 The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (P<0.01). Less potent nootropics, D-levetiracetam and D-pyroglutamate, have higher antagonist Ki's against pentobarbital inhibition of glucose transport than more potent L-stereoisomers (P<0.001). 3 Piracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. 4 There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. 5 Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis.
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Affiliation(s)
- Richard J Naftalin
- Physiology Division, Centre for Vascular Biology and Medicine, King's College London, Guy's Campus, New Hunt's House, London SE1 1UL.
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Wrenn CC, Kinney JW, Marriott LK, Holmes A, Harris AP, Saavedra MC, Starosta G, Innerfield CE, Jacoby AS, Shine J, Iismaa TP, Wenk GL, Crawley JN. Learning and memory performance in mice lacking the GAL-R1 subtype of galanin receptor. Eur J Neurosci 2004; 19:1384-96. [PMID: 15016096 DOI: 10.1111/j.1460-9568.2004.03214.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The neuropeptide galanin induces performance deficits in a wide range of cognitive tasks in rodents. Three G-protein-coupled galanin receptor subtypes, designated GAL-R1, GAL-R2 and GAL-R3, have been cloned. The present study examined the role of GAL-R1 in cognition by testing mice with a null mutation in Galr1 on several different types of learning and memory tasks. Assessments of general health, neurological reflexes, sensory abilities and motor functions were conducted as control measures. Mutant mice were unimpaired in social transmission of food preference and the Morris water maze. In tests of fear conditioning, mutant mice were unimpaired in a delay version of cued fear conditioning. However, mice homozygous for the null mutation were impaired in a trace version of cued fear conditioning. Mutant mice were unimpaired in contextual fear conditioning, whether training was by the delay or trace protocol. General health, neurological reflexes, sensory abilities and motor functions did not differ across genotypes, indicating that the trace fear conditioning deficit was not an artifact of procedural disabilities. The findings of normal performance on several cognitive tasks and a selective deficit in trace cued fear conditioning in homozygous GAL-R1 mutant mice are discussed in terms of hypothesized roles of the GAL-R1 subtype. The generally normal phenotype of GAL-R1 null mutants supports the use of this line for identification of the receptor subtypes that mediate the cognitive deficits produced by exogenous galanin.
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Affiliation(s)
- Craige C Wrenn
- Laboratory of Behavioural Neuroscience, National Institute of Mental Health, Bethesda, MD 20892-1375, USA.
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Chang Q, Gold PE. Impaired and spared cholinergic functions in the hippocampus after lesions of the medial septum/vertical limb of the diagonal band with 192 IgG-saporin. Hippocampus 2004; 14:170-9. [PMID: 15098723 DOI: 10.1002/hipo.10160] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
To lesion the cholinergic input to the hippocampus, rats received injections of 192 IgG-saporin into the medial septum/vertical limb of the diagonal band (MS/VDB). The lesions produced near-total loss of choline acetyltransferase (ChAT)-positive neurons in the MS/VDB. The loss was accompanied, however, by only partial decreases (to 40% of control levels) in acetylcholine (ACh) release in the hippocampus. Moreover, ACh release in the hippocampus increased when lesioned and control rats were tested on a spontaneous alternation task, indicating that there was significant residual cholinergic function in the hippocampus. The lesions were sufficient to impair spontaneous alternation scores. However, this impairment could be reversed by either systemic or intra-hippocampal injections of the indirect cholinergic agonist, physostigmine, providing additional evidence of residual and effective cholinergic functions in the hippocampus of lesioned rats. Moreover, systemic injections of physostigmine at doses that produced mild tremors in control rats led to more severe tremors in the lesioned rats, suggesting upregulation of cholinergic mechanisms after saporin lesions, likely in brain areas other than the hippocampus. Thus, these findings provide evidence for decreases in cholinergic input to the hippocampus accompanied by deficits on a spontaneous alternation tasks. The findings also provide evidence for considerable residual cholinergic input to the hippocampus after saporin lesions of the MS/VDB. Together, the results suggest that 192 IgG-saporin lesions of the MS/VDB, using methods often employed, do not fully remove septohippocampal cholinergic input to the hippocampus but are nonetheless sufficient to produce impairments on a task impaired by hippocampal lesions.
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Affiliation(s)
- Qing Chang
- Department of Psychology, University of Illinois, 603 East Daniel Street, Champaign, IL 61820, USA
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Kinney JW, Starosta G, Crawley JN. Central galanin administration blocks consolidation of spatial learning. Neurobiol Learn Mem 2003; 80:42-54. [PMID: 12737933 DOI: 10.1016/s1074-7427(03)00023-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Galanin is a neuropeptide that inhibits the evoked release of several neurotransmitters, inhibits the activation of intracellular second messengers, and produces deficits in a variety of rodent learning and memory tasks. To evaluate the actions of galanin on encoding, consolidation, and storage/retrieval, galanin was acutely administered to Sprague-Dawley rats at time points before and after training trials in the Morris water maze. Intraventricular administration of galanin up to 3h after subjects had completed daily training trials in the Morris water task impaired performance on the probe trial, indicating that galanin-blocked consolidation. Pretreatment with an adenylate cyclase activator, forskolin, prevented the deficits in distal cue learning produced by galanin. Di-deoxyforskolin, an inactive analog of forskolin, had no effect. These results provide the first evidence that galanin interferes with long-term memory consolidation processes. A potential mechanism by which galanin produces this impairment may involve the inhibition of adenylate cyclase activity, leading to inhibition of downstream molecular events that are necessary for consolidation of long-term memory.
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Affiliation(s)
- Jefferson W Kinney
- Section on Behavioral Genomics, National Institute of Mental Health, Galanin Inhibits Consolidation, Building 10 Room 4011, Bethesda, MD 20892-1375, USA.
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Hill RA, Rudra S, Peng B, Roane DS, Bounds JK, Zhang Y, Adloo A, Lu T. Hydroxyl-substituted sulfonylureas as potent inhibitors of specific [3H]glyburide binding to rat brain synaptosomes. Bioorg Med Chem 2003; 11:2099-113. [PMID: 12670661 DOI: 10.1016/s0968-0896(02)00606-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We are seeking to discover potent CNS-active sulfonylureas with structural features that allow for the formation of several types of prodrugs. We report herein the syntheses of compounds comprising an initial series of hydroxyl-substituted analogues of the potent ATP-sensitive potassium channel blockers glyburide (glibenclamide) and gliquidone. Somewhat unexpectedly, several of the compounds were found to be comparably potent to glyburide as inhibitors of specific [(3)H]glyburide binding in rat brain preparations.
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Affiliation(s)
- Ronald A Hill
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, The University of Louisiana at Monroe, Monroe, LA 71209, USA.
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Shah AA, Parent MB. Septal infusions of glucose or pyruvate, but not fructose, produce avoidance deficits when co-infused with the GABA agonist muscimol. Neurobiol Learn Mem 2003; 79:243-51. [PMID: 12676523 DOI: 10.1016/s1074-7427(03)00007-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although glucose typically enhances memory or reverses memory deficits, glucose can also produce memory deficits when co-infused with the gamma-aminobutyric acid (GABA) agonist muscimol into the medial septum (Parent & Gold, 1997; Parent, Laurey, Wilkniss, & Gold, 1997). To date the mechanisms underlying the memory-impairing interaction between GABA and glucose remain unknown. Here we investigate whether this effect is the result of hyperosmolar conditions or may involve glucose metabolism. Male Sprague-Dawley rats were given one-trial inhibitory avoidance training after receiving septal infusions of vehicle (phosphate-buffered saline, 0.5 microl), the GABA(A) agonist muscimol (3 nmol), glucose (16.5, 33, or 66 nmol), fructose (33 nmol), pyruvate (33 nmol), or a solution containing muscimol combined with glucose, fructose, or pyruvate. Retention performance was tested 48 h later. Infusions of glucose, pyruvate, fructose, or muscimol alone did not affect retention performance. However, co-infusions of all doses of glucose (16.5, 33, or 66 nmol) or the glycolytic end product pyruvate with muscimol impaired retention performance. Co-infusions of fructose with muscimol did not affect retention performance. These results suggest that the memory-impairing interaction between glucose and muscimol does not result from hyperosmolar conditions, because equiosmolar concentrations of fructose do not mimic the effects of glucose and the memory deficits do not vary as a function of glucose concentration. The finding that pyruvate mimicked the effects of glucose and impaired memory when combined with muscimol suggests that glucose metabolism may be involved in the memory-impairing interaction between glucose and GABA(A) receptors in the medial septum.
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Affiliation(s)
- Akeel A Shah
- Department of Psychology, University of Alberta, Edmonton, Alb., T6G 2E9, Canada
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McIntyre CK, Marriott LK, Gold PE. Cooperation between memory systems: acetylcholine release in the amygdala correlates positively with performance on a hippocampus-dependent task. Behav Neurosci 2003; 117:320-6. [PMID: 12708528 DOI: 10.1037/0735-7044.117.2.320] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present experiment examined the relationship between release of acetylcholine (ACh) in the amygdala and performance on a hippocampus-dependent spatial working memory task. Using in vivo microdialysis, the authors measured ACh release in rats during testing on a spontaneous alternation task. Amygdala ACh release was positively correlated with performance on the hippocampus-dependent task. These findings suggest that activation of the amygdala promotes processing in other neural systems important for learning and memory.
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Affiliation(s)
- Christa K McIntyre
- Department of Neurobiology and Behavior, University of California, Irvine, USA
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Heininger K. The cerebral glucose-fatty acid cycle: evolutionary roots, regulation, and (patho)physiological importance. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 51:103-58. [PMID: 12420358 DOI: 10.1016/s0074-7742(02)51004-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Kurt Heininger
- Department of Neurology, Heinrich Heine University, D-40597 Düsseldorf, Germany
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Social transmission of food preference in mice: Methodology and application to galanin-overexpressing transgenic mice. Behav Neurosci 2003. [DOI: 10.1037/0735-7044.117.1.21] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Talley CP, Clayborn H, Jewel E, McCarty R, Gold PE. Vagotomy attenuates effects of L-glucose but not of D-glucose on spontaneous alternation performance. Physiol Behav 2002; 77:243-9. [PMID: 12419400 DOI: 10.1016/s0031-9384(02)00850-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Two peripheral signaling routes have been proposed to account for the ability of peripheral substances such as glucose to modulate memory processing in the brain. One possible signaling route is by crossing the blood-brain barrier to act directly on brain. A second route involves activation of peripheral nerves with resulting changes in neural activity carried by peripheral nerves to the brain. Because the vagus nerve is a major neural pathway between the periphery and brain, peripherally acting modulators of memory modulators may act via vagal afferents to the brain to enhance memory processing. In the present experiments, systemic injections of either D-glucose or L-glucose, a metabolically inactive enantiomer, facilitated performance of rats on a four-arm alternation task, but at very different doses (D-glucose, 250 mg/kg; L-glucose, 3,000 mg/kg). The enhanced performance seen with L-glucose, but not that seen with D-glucose, was attenuated by vagotomy. These findings suggest that the mechanisms by which these enantiomers act to enhance memory are quite different, with L-glucose acting via vagal afferents but D-glucose acting by other means, including direct modulation of central nervous system (CNS) processes by D-glucose.
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Affiliation(s)
- Cheryl P Talley
- School of Psychology, James Madison University, Harrisonburg, VA 22801, USA.
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Kinney JW, Starosta G, Holmes A, Wrenn CC, Yang RJ, Harris AP, Long KC, Crawley JN. Deficits in trace cued fear conditioning in galanin-treated rats and galanin-overexpressing transgenic mice. Learn Mem 2002; 9:178-90. [PMID: 12177231 PMCID: PMC182584 DOI: 10.1101/m.49502] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Galanin inhibits the release of several neurotransmitters and produces performance deficits in a variety of spatial and aversive learning and memory tasks. The experiments in this study investigated the role galanin has in emotional learning and memory using a standard delay cued and contextual fear conditioning task. Rats were administered galanin into the lateral ventricles before training, and scored for freezing behavior in the same context and in a novel context with and without an auditory cue (CS) that had been paired previously with an aversive stimulus (US). Galanin-overexpressing transgenic mice were tested in an identical behavioral protocol. The galanin-administered rats and the transgenic mice were not significantly different from their respective controls on this task. A more challenging trace cued and contextual fear conditioning procedure was administered to separate groups of galanin-treated rats and galanin-overexpressing transgenic mice. Subjects were trained with the same CS and US, however, a 2.5-sec delay was inserted between CS offset and US onset. Following the trace conditioning, rats administered galanin and mice overexpressing galanin both exhibited significantly less freezing to the CS in the novel context as compared with their control groups. These results indicate that the observed disruption of cued fear conditioning was specific to the more difficult trace conditioning task. These findings are the first demonstration that galanin impairs performance on an emotional memory task and support the hypothesis that galanin-induced deficits are specific to more difficult cognitive tasks.
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Affiliation(s)
- Jefferson W Kinney
- Section on Behavioral Genomics, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
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Abstract
Galanin is a neuroendocrine peptide involved in the regulation of feeding, pain, sexual behavior, learning, and memory. The recent discovery, that galanin antagonized excitatory glutamatergic neurotransmission in the hippocampus, provided a rationale for its possible antiepileptic effects. Here we summarize the data on the effects of galanin on seizure activity in several animal models of epilepsy. Pharmacological and molecular biological evidence suggest potent anticonvulsant effects of galanin. Exogenous administration of galanin receptor agonists attenuated seizures, whereas application of galanin receptor antagonists potentiated seizure expression. Genetically engineered mice, with either deletion or overexpression of galanin gene, showed altered resistance to seizures, which was in direct correlation with galanin gene expression. Possible mechanisms of the anticonvulsant action of galanin include its effects on synaptic potentiation in hippocampal circuits and inhibition of the release of the excitatory neurotransmitter glutamate from principal hippocampal neurons.
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Affiliation(s)
- A Mazarati
- Department of Neurology, UCLA School of Medicine and West LA VA Medical Center, Los Angeles, CA 90073, USA.
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