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Dobryakova YV, Gerasimov K, Spivak YS, Korotkova T, Koryagina A, Deryabina A, Markevich VA, Bolshakov AP. The Induction of Long-Term Potentiation by Medial Septum Activation under Urethane Anesthesia Can Alter Gene Expression in the Hippocampus. Int J Mol Sci 2023; 24:12970. [PMID: 37629149 PMCID: PMC10454684 DOI: 10.3390/ijms241612970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
We studied changes in the expression of early genes in hippocampal cells in response to stimulation of the dorsal medial septal area (dMSA), leading to long-term potentiation in the hippocampus. Rats under urethane anesthesia were implanted with stimulating electrodes in the ventral hippocampal commissure and dMSA and a recording electrode in the CA1 area of the hippocampus. We found that high-frequency stimulation (HFS) of the dMSA led to the induction of long-term potentiation in the synapses formed by the ventral hippocampal commissure on the hippocampal CA1 neurons. One hour after dMSA HFS, we collected the dorsal and ventral hippocampi on both the ipsilateral (damaged by the implanted electrode) and contralateral (intact) sides and analyzed the expression of genes by qPCR. The dMSA HFS led to an increase in the expression of bdnf and cyr61 in the ipsilateral hippocampi and egr1 in the ventral contralateral hippocampus. Thus, dMSA HFS under the conditions of degeneration of the cholinergic neurons in the medial septal area prevented the described increase in gene expression. The changes in cyr61 expression appeared to be dependent on the muscarinic M1 receptors. Our data suggest that the induction of long-term potentiation by dMSA activation enhances the expression of select early genes in the hippocampus.
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Affiliation(s)
| | | | | | | | | | | | | | - Alexey P. Bolshakov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 117485 Moscow, Russia (K.G.)
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Dobryakova YV, Spivak YS, Zaichenko MI, Koryagina AA, Markevich VA, Stepanichev MY, Bolshakov AP. Intrahippocampal Adeno-Associated Virus-Mediated Overexpression of Nerve Growth Factor Reverses 192IgG-Saporin-Induced Impairments of Hippocampal Plasticity and Behavior. Front Neurosci 2021; 15:745050. [PMID: 34867156 PMCID: PMC8634591 DOI: 10.3389/fnins.2021.745050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022] Open
Abstract
One of the aspects of Alzheimer disease is loss of cholinergic neurons in the basal forebrain, which leads to development of cognitive impairment. Here, we used a model of cholinergic deficit caused by immunotoxin 192IgG-saporin to study possible beneficial effects of adeno-associated virus (AAV)-mediated overexpression of nerve growth factor (NGF) in the hippocampus of rats with cholinergic deficit. Suspension of recombinant AAV carrying control cassette or cassette with NGF was injected into both hippocampi of control rats or rats with cholinergic deficit induced by intraseptal injection of 192IgG-saporin. Analysis of choline acetyltransferase (ChAT) immunostaining showed that NGF overexpression in the hippocampus did not prevent strong loss of ChAT-positive neurons in the septal area caused by the immunotoxin. Induction of cholinergic deficit in the hippocampus led to impairments in Y-maze and beam-walking test but did not affect behavioral indices in the T-maze, open field test, and inhibitory avoidance training. NGF overexpression in the rats with cholinergic deficit restored normal animal behavior in Y-maze and beam-walking test. Recording of field excitatory postsynaptic potentials in vivo in the hippocampal CA1 area showed that induction of cholinergic deficit decreased magnitude of long-term potentiation (LTP) and prevented a decrease in paired-pulse ratio after LTP induction, and NGF overexpression reversed these negative changes in hippocampal synaptic characteristics. The beneficial effect of NGF was not associated with compensatory changes in the number of cells that express NGF receptors TrkA and NGFR in the hippocampus and medial septal area. NGF overexpression also did not prevent a 192IgG-saporin-induced decrease in the activity of acetylcholine esterase in the hippocampus. We conclude that NGF overexpression in the hippocampus under conditions of cholinergic deficit induces beneficial effects which are not related to maintenance of cholinergic function.
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Affiliation(s)
| | | | | | | | | | | | - Alexey P. Bolshakov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
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Llorente-Ovejero A, Martínez-Gardeazabal J, Moreno-Rodríguez M, Lombardero L, González de San Román E, Manuel I, Giralt MT, Rodríguez-Puertas R. Specific Phospholipid Modulation by Muscarinic Signaling in a Rat Lesion Model of Alzheimer's Disease. ACS Chem Neurosci 2021; 12:2167-2181. [PMID: 34037379 PMCID: PMC9162383 DOI: 10.1021/acschemneuro.1c00169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
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Alzheimer’s disease (AD) represents
the most common cause
of dementia worldwide and has been consistently associated with the
loss of basal forebrain cholinergic neurons (BFCNs) leading to impaired
cholinergic neurotransmission, aberrant synaptic function, and altered
structural lipid metabolism. In this sense, membrane phospholipids
(PLs) can be used for de novo synthesis of choline (Ch) for the further
obtaining of acetylcholine (ACh) when its availability is compromised.
Specific lipid species involved in the metabolism of Ch have been
identified as possible biomarkers of phenoconversion to AD. Using
a rat model of BFCN lesion, we have evaluated the lipid composition
and muscarinic signaling in brain areas related to cognitive processes.
The loss of BFCN resulted in alterations of varied lipid species related
to Ch metabolism at nucleus basalis magnocellularis (NMB) and cortical
projection areas. The activity of muscarinic receptors (mAChR) was
decreased in the NMB and increased in the hippocampus according to
the subcellular distribution of M1/M2 mAChR
which could explain the learning and memory impairment reported in
this AD rat model. These results suggest that the modulation of specific
lipid metabolic routes could represent an alternative therapeutic
strategy to potentiate cholinergic neurotransmission and preserve
cell membrane integrity in AD.
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Affiliation(s)
- Alberto Llorente-Ovejero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Jonatan Martínez-Gardeazabal
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Marta Moreno-Rodríguez
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Laura Lombardero
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Estíbaliz González de San Román
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
- Neurodegenerative Diseases, BioCruces Bizkaia Health Research Institute, 48903 Barakaldo, Spain
| | - María Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
- Neurodegenerative Diseases, BioCruces Bizkaia Health Research Institute, 48903 Barakaldo, Spain
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Dobryakova YV, Stepanichev MY, Markevich VA, Bolshakov AP. Long-term potentiation in the hippocampal CA3 to CA1 synapses may be induced in vivo by activation of septal cholinergic inputs. Int J Neurosci 2020; 132:1-7. [PMID: 32916077 DOI: 10.1080/00207454.2020.1822834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/27/2020] [Accepted: 09/04/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE/AIM The role of cholinergic neurotransmission in the hippocampus remains controversial since different studies showed either no influence or its modulatory effect on glutamatergic hippocampal synapses. It remains unclear whether septal cholinergic input can modulate plasticity of synapses formed by CA3 pyramids on CA1 neurons. The aim of the study was to clarify the role of septal input in the development of LTP in this synapse. MATERIALS AND METHODS We recorded in vivo in rats under urethane anesthesia focal excitatory postsynaptic potential (fEPSP) characteristics in CA1 area after stimulation of the ventral hippocampal commissure (VHC), which contains both CA3 axons innervating CA1 neurons and cholinergic axons coming from the medial septum. We performed two series of experiments in which LTP was induced by tetanization of either VHC or medial septal area (MSA). Degeneration of cholinergic neurons in MSA was induced by intraseptal injection of 192IgG-saporin. RESULTS In both experimental series, tetanization induced an increase in fEPSP amplitude which lasted for at least 40 min after tetanic stimulation, although tetanization of VHC induced a larger increase in fEPSP amplitude compared to MSA tetanization. Elimination of septal cholinergic neurons by 192IgG-saporin abolished LTP development in both experimental series. This suppression of LTP in animals with cholinergic deficit was not due to loss of hippocampal neurons. CONCLUSIONS Our data suggest that activation of septal cholinergic fibers during tetanization is a critical factor of LTP induction in the hippocampal CA3 to CA1 synapses.
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Affiliation(s)
- Y V Dobryakova
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - M Yu Stepanichev
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - V A Markevich
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
| | - A P Bolshakov
- Neurophysiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia
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Bolshakov AP, Stepanichev MY, Dobryakova YV, Spivak YS, Markevich VA. Saporin from Saponaria officinalis as a Tool for Experimental Research, Modeling, and Therapy in Neuroscience. Toxins (Basel) 2020; 12:toxins12090546. [PMID: 32854372 PMCID: PMC7551693 DOI: 10.3390/toxins12090546] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 01/06/2023] Open
Abstract
Saporin, which is extracted from Saponaria officinalis, is a protein toxin that inactivates ribosomes. Saporin itself is non-selective toxin but acquires high specificity after conjugation with different ligands such as signaling peptides or antibodies to some surface proteins expressed in a chosen cell subpopulation. The saporin-based conjugated toxins were widely adopted in neuroscience as a convenient tool to induce highly selective degeneration of desired cell subpopulation. Induction of selective cell death is one of approaches used to model neurodegenerative diseases, study functions of certain cell subpopulations in the brain, and therapy. Here, we review studies where saporin-based conjugates were used to analyze cell mechanisms of sleep, general anesthesia, epilepsy, pain, and development of Parkinson’s and Alzheimer’s diseases. Limitations and future perspectives of use of saporin-based toxins in neuroscience are discussed.
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Affiliation(s)
- Alexey P. Bolshakov
- Laboratory of Molecular Neurobiology, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
- Correspondence:
| | - Mikhail Yu. Stepanichev
- Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Yulia V. Dobryakova
- Laboratory of Neurophysiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.V.D.); (V.A.M.)
| | - Yulia S. Spivak
- Laboratory of Molecular Neurobiology, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Vladimir A. Markevich
- Laboratory of Neurophysiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.V.D.); (V.A.M.)
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Dobryakova YV, Volobueva MN, Manolova AO, Medvedeva TM, Kvichansky AA, Gulyaeva NV, Markevich VA, Stepanichev MY, Bolshakov AP. Cholinergic Deficit Induced by Central Administration of 192IgG-Saporin Is Associated With Activation of Microglia and Cell Loss in the Dorsal Hippocampus of Rats. Front Neurosci 2019; 13:146. [PMID: 30930730 PMCID: PMC6424051 DOI: 10.3389/fnins.2019.00146] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/08/2019] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD) is associated with degeneration of cholinergic neurons in the basal forebrain. Administration of the immunotoxin 192IgG-saporin to rats, an animal model of AD, leads to degeneration of cholinergic neurons in the medial septal area. In the present study, cholinergic cell death was induced by intracerebroventricular administration of 192IgG-saporin. One and a half months after injection, we studied the histopathology of the hippocampus and the responses of microglia and astrocytes using immunohistochemistry and neuroglial gene expression. We found that treatment with 192IgG-saporin resulted in neuronal loss in the CA3 field of the hippocampus. Microglial proliferation was observed in the dentate gyrus of the dorsal hippocampus and white matter. Massive proliferation and activation of microglia in the white matter was associated with strong activation of astrocytes. However, the expression of microglial marker genes significantly increased only in the dorsal hippocampus, not the ventral hippocampus. These effects were not related to non-specific action of 192IgG-saporin because of the absence of the Nerve growth factor receptor in the hippocampus. Additionally, 192IgG-saporin treatment also induced a decrease in the expression of genes that are associated with transport functions of brain vascular cells (Slc22a8, Ptprb, Sdpr), again in the dorsal hippocampus but not in the ventral hippocampus. Taken together, our data suggest that cholinergic degeneration in the medial septal area induced by intracerebroventricular administration of 192IgG-saporin results in an increase in the number of microglial cells and neuron degeneration in the dorsal hippocampus.
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Affiliation(s)
- Yulia V Dobryakova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Maria N Volobueva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Anna O Manolova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Tatiana M Medvedeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Alexey A Kvichansky
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Natalia V Gulyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Vlamidir A Markevich
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail Yu Stepanichev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Alexey P Bolshakov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.,Research Laboratory of Electrophysiology, Pirogov Russian National Research Medical University, Moscow, Russia
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Li J, Rao D, Gibbs RB. Effects of Cholinergic Lesions and Cholinesterase Inhibitors on Aromatase and Estrogen Receptor Expression in Different Regions of the Rat Brain. Neuroscience 2018; 384:203-213. [PMID: 29852246 DOI: 10.1016/j.neuroscience.2018.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/07/2018] [Accepted: 05/21/2018] [Indexed: 11/28/2022]
Abstract
Cholinergic projections have been shown to interact with estrogens in ways that influence synaptic plasticity and cognitive performance. The mechanisms are not well understood. The goal of this study was to investigate whether cholinergic projections influence brain estrogen production by affecting aromatase (ARO), or influence estrogen signaling by affecting estrogen receptor expression. In the first experiment, ovariectomized rats received intraseptal injection of the selective immunotoxin 192IgG-saporin to destroy cholinergic inputs to the hippocampus. In the second experiment ovariectomized rats received daily intraperitoneal injections of the cholinesterase inhibitors donepezil or galantamine for 1 week. ARO activity and relative levels of ARO, ERα, ERß, and GPR30 mRNAs were quantified in the hippocampus, frontal cortex, amygdala and preoptic area. Results show that the cholinergic lesions effectively removed cholinergic inputs to the hippocampus, but had no significant effect on ARO or on relative levels of ER mRNAs. Likewise, injections of the cholinesterase inhibitors had no effect on ARO or ER expression in most regions of the brain. This suggests that effects of cholinergic inputs on synaptic plasticity and neuronal function are not mediated by effects on local estrogen production or ER expression. One exception was the amygdala where treating with galantamine was associated with a significant increase in ARO activity. The amygdala is a key structure involved in registering fear and anxiety. Hence this finding may be clinically relevant to elderly patients who are treated for memory impairment and who also struggle with fear and anxiety disorders.
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Affiliation(s)
- Junyi Li
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Di Rao
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Robert B Gibbs
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Dobryakova YV, Kasianov A, Zaichenko MI, Stepanichev MY, Chesnokova EA, Kolosov PM, Markevich VA, Bolshakov AP. Intracerebroventricular Administration of 192IgG-Saporin Alters Expression of Microglia-Associated Genes in the Dorsal But Not Ventral Hippocampus. Front Mol Neurosci 2018; 10:429. [PMID: 29386992 PMCID: PMC5776139 DOI: 10.3389/fnmol.2017.00429] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 12/11/2017] [Indexed: 11/23/2022] Open
Abstract
One of important aspects of development of Alzheimer’s disease is degeneration of septal cholinergic neurons that innervate the hippocampus. We took advantage of widely used model of cholinergic deficit in the hippocampus, intracerebroventricular administration of 192IgG-saporin (Ig-saporin), to analyze the postponed consequences of cholinergic deficit in different parts of the hippocampus. We studied effects of the immunotoxin on the behavior of rats and gene expression in the dorsal and ventral hippocampus using RNA-seq approach. We found that under normal conditions dorsal and ventral parts of the hippocampus differ in the expression of 1129 protein-coding genes and 49 non-coding RNAs (ncRNAs) and do not differ in the expression of 10 microRNAs, which were detected in both parts of the hippocampus. Ig-saporin-induced degeneration of cholinergic septal neurons did not affect rat behavior in open field, T-maze, and passive avoidance task but impaired memory retention in Morris water maze. To analyze 192Ig-saporin-induced changes in the gene expression, we formed the following groups of genes: genes expressed exclusively in certain cell types (neurons, astrocytes, microglia, oligodendrocytes, and vascular cells) and, among universally expressed genes, a group of genes that encode ribosome-forming proteins. For all groups of genes, the alterations in the gene expression produced by the immunotoxin were stronger in the dorsal as compared to the ventral hippocampus. We found that, among groups of universally expressed genes, Ig-saporin increased the expression of ribosome-forming proteins in both dorsal and ventral hippocampus. Ig-saporin also strongly upregulated expression of microglia-specific genes only in the dorsal hippocampus. A subset of affected microglial genes comprised genes associated with inflammation, however, did not include genes related to acute inflammation such as interleukins-1b, -6, -15, and -18 as well as TNF. The expression of other cell-specific genes (genes specific for neurons, astrocytes, oligodendrocytes, and vascular cells) was unaffected. The data obtained suggest that disturbance of memory-associated behavior after administration of Ig-saporin is associated with upregulation of microglia-associated genes in the dorsal but not ventral hippocampus.
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Affiliation(s)
- Yulia V Dobryakova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Artem Kasianov
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Maria I Zaichenko
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail Y Stepanichev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina A Chesnokova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Petr M Kolosov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Vladimir A Markevich
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Alexey P Bolshakov
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
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Llorente-Ovejero A, Manuel I, Giralt MT, Rodríguez-Puertas R. Increase in cortical endocannabinoid signaling in a rat model of basal forebrain cholinergic dysfunction. Neuroscience 2017; 362:206-218. [PMID: 28827178 DOI: 10.1016/j.neuroscience.2017.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/20/2017] [Accepted: 08/03/2017] [Indexed: 12/24/2022]
Abstract
The basal forebrain cholinergic pathways progressively degenerate during the progression of Alzheimer's disease, leading to an irreversible impairment of memory and thinking skills. The stereotaxic lesion with 192IgG-saporin in the rat brain has been used to eliminate basal forebrain cholinergic neurons and is aimed at emulating the cognitive damage described in this disease in order to explore its effects on behavior and on neurotransmission. Learning and memory processes that are controlled by cholinergic neurotransmission are also modulated by the endocannabinoid (eCB) system. The objective of the present study is to evaluate the eCB signaling in relation to the memory impairment induced in adult rats following a specific cholinergic lesion of the basal forebrain. Therefore, CB1 receptor-mediated signaling was analyzed using receptor and functional autoradiography, and cellular distribution by immunofluorescence. The passive avoidance test and histochemical data revealed a relationship between impaired behavioral responses and a loss of approximately 75% of cholinergic neurons in the nucleus basalis magnocellularis (NBM), accompanied by cortical cholinergic denervation. The decrease in CB1 receptor density observed in the hippocampus, together with hyperactivity of eCB signaling in the NBM and cortex, suggest an interaction between the eCB and cholinergic systems. Moreover, following basal forebrain cholinergic denervation, the presynaptic GABAergic immunoreactivity was reduced in cortical areas. In conclusion, CB1 receptors present in presynaptic GABAergic terminals in the hippocampus are down regulated, but not those in cortical glutamatergic synapses.
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Affiliation(s)
- Alberto Llorente-Ovejero
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Maria Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Nursing. University of the Basque Country (UPV/EHU), B° Sarriena s/n, 48940 Leioa, Spain.
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