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Ronchetti S, Labombarda F, Roig P, De Nicola AF, Pietranera L. Beneficial effects of the phytoestrogen genistein on hippocampal impairments of spontaneously hypertensive rats (SHR). J Neuroendocrinol 2023; 35:e13228. [PMID: 36690381 DOI: 10.1111/jne.13228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/09/2022] [Accepted: 12/19/2022] [Indexed: 01/05/2023]
Abstract
Hippocampal neuropathology is a recognized feature of the spontaneously hypertensive rat (SHR). The hippocampal alterations associate with cognitive impairment. We have shown that hippocampal abnormalities are reversed by 17β-estradiol, a steroid binding to intracellular receptors (estrogen receptor α and β subtypes) or the membrane-located G-protein coupled estradiol receptor. Genistein (GEN) is a neuroprotective phytoestrogen which binds to estrogen receptor β and G-protein coupled estradiol receptor. Here, we investigated whether GEN neuroprotection extends to SHR. For this purpose, we treated 5-month-old SHR for 2 weeks with 10 mg kg-1 daily s.c injections of GEN. We analyzed the expression of doublecortin+ neuronal progenitors, glial fibrillary acidic protein+ astrocytes and ionized calcium-binding adapter molecule 1+ microglia in the CA1 region and dentate gyrus of the hippocampus using immunocytochemistry, whereas a quantitative real-time polymerase chain reaction was used to measure the expression of pro- and anti-inflammatory factors tumor necrosis factor α, cyclooxygenase-2 and transforming growth factor β. We also evaluated hippocampal dependent memory using the novel object recognition test. The results showed a decreased number of doublecortin+ neural progenitors in the dentate gyrus of SHR that was reversed with GEN. The number of glial fibrillary acidic protein+ astrocytes in the dentate gyrus and CA1 was increased in SHR but significantly decreased by GEN treatment. Additionally, GEN shifted microglial morphology from the predominantly activated phenotype present in SHR, to the more surveillance phenotype found in normotensive rats. Furthermore, treatment with GEN decreased the mRNA of the pro-inflammatory factors tumor necrosis factor α and cyclooxygenase-2 and increased the mRNA of the anti-inflammatory factor transforming growth factor β. Discrimination index in the novel object recognition test was decreased in SHR and treatment with GEN increased this parameter. Our results indicate important neuroprotective effects of GEN at the neurochemical and behavioral level in SHR. Our data open an interesting possibility for proposing this phytoestrogen as an alternative therapy in hypertensive encephalopathy.
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Affiliation(s)
- Santiago Ronchetti
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
| | - Florencia Labombarda
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
- Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Paulina Roig
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
| | - Alejandro F De Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
- Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Luciana Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina
- Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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IGF1 Gene Therapy Reversed Cognitive Deficits and Restored Hippocampal Alterations After Chronic Spinal Cord Injury. Mol Neurobiol 2021; 58:6186-6202. [PMID: 34463925 DOI: 10.1007/s12035-021-02545-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 08/22/2021] [Indexed: 10/20/2022]
Abstract
The hippocampus is implicated in the generation of memory and learning, processes which involve extensive neuroplasticity. The generation of hippocampal adult-born neurons is particularly regulated by glial cells of the neurogenic niche and the surrounding microenvironment. Interestingly, recent evidence has shown that spinal cord injury (SCI) in rodents leads to hippocampal neuroinflammation, neurogenesis reduction, and cognitive impairments. In this scenario, the aim of this work was to evaluate whether an adenoviral vector expressing IGF1 could reverse hippocampal alterations and cognitive deficits after chronic SCI. SCI caused neurogenesis reduction and impairments of both recognition and working memories. We also found that SCI increased the number of hypertrophic arginase-1 negative microglia concomitant with the decrease of the number of ramified surveillance microglia in the hilus, molecular layer, and subgranular zone of the dentate gyrus. RAd-IGF1 treatment restored neurogenesis and improved recognition and working memory impairments. In addition, RAd-IGF1 gene therapy modulated differentially hippocampal regions. In the hilus and molecular layer, IGF1 gene therapy recovered the number of surveillance microglia coincident with a reduction of hypertrophic microglia cell number. However, in the neurogenic niche, IGF1 reduced the number of ramified microglia and increased the number of hypertrophic microglia, which as a whole expressed arginase-1. In summary, RAd-IGF1 gene therapy might surge as a new therapeutic strategy for patients with hippocampal microglial alterations and cognitive deficits such as those with spinal cord injury and other neurodegenerative diseases.
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Jure I, De Nicola AF, Encinas JM, Labombarda F. Spinal Cord Injury Leads to Hippocampal Glial Alterations and Neural Stem Cell Inactivation. Cell Mol Neurobiol 2020; 42:197-215. [PMID: 32537668 DOI: 10.1007/s10571-020-00900-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 06/06/2020] [Indexed: 12/12/2022]
Abstract
The hippocampus encodes spatial and contextual information involved in memory and learning. The incorporation of new neurons into hippocampal networks increases neuroplasticity and enhances hippocampal-dependent learning performances. Only few studies have described hippocampal abnormalities after spinal cord injury (SCI) although cognitive deficits related to hippocampal function have been reported in rodents and even humans. The aim of this study was to characterize in further detail hippocampal changes in the acute and chronic SCI. Our data suggested that neurogenesis reduction in the acute phase after SCI could be due to enhanced death of amplifying neural progenitors (ANPs). In addition, astrocytes became reactive and microglial cells increased their number in almost all hippocampal regions studied. Glial changes resulted in a non-inflammatory response as the mRNAs of the major pro-inflammatory cytokines (IL-1β, TNFα, IL-18) remained unaltered, but CD200R mRNA levels were downregulated. Long-term after SCI, astrocytes remained reactive but on the other hand, microglial cell density decreased. Also, glial cells induced a neuroinflammatory environment with the upregulation of IL-1β, TNFα and IL-18 mRNA expression and the decrease of CD200R mRNA. Neurogenesis reduction may be ascribed at later time points to inactivation of neural stem cells (NSCs) and inhibition of ANP proliferation. The number of granular cells and CA1 pyramidal neurons decreased only in the chronic phase. The release of pro-inflammatory cytokines at the chronic phase might involve neurogenesis reduction and neurodegeneration of hippocampal neurons. Therefore, SCI led to hippocampal changes that could be implicated in cognitive deficits observed in rodents and humans.
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Affiliation(s)
- Ignacio Jure
- Laboratory of Neuroendocrine Biochemistry, IBYME-CONICET., Instituto de Biologia Y Medicina Experimental, Vuelta de Obligado 2490, 1428, Buenos Aires, Argentina
| | - Alejandro F De Nicola
- Laboratory of Neuroendocrine Biochemistry, IBYME-CONICET., Instituto de Biologia Y Medicina Experimental, Vuelta de Obligado 2490, 1428, Buenos Aires, Argentina.,Department of Human Biochemistry, School of Medicine, Buenos Aires University, Paraguay 2155, C1121A6B, Buenos Aires, Argentina
| | - Juan Manuel Encinas
- Laboratory of Neural Stem Cells and Neurogenesis, Achucarro Basque Center for Neuroscience. Sede Bldg. Campus, UPV/EHU, Barrio Sarriena S/N, 48940, Leioa, Spain
| | - Florencia Labombarda
- Laboratory of Neuroendocrine Biochemistry, IBYME-CONICET., Instituto de Biologia Y Medicina Experimental, Vuelta de Obligado 2490, 1428, Buenos Aires, Argentina. .,Department of Human Biochemistry, School of Medicine, Buenos Aires University, Paraguay 2155, C1121A6B, Buenos Aires, Argentina.
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Pechlivanova D, Krumova E, Kostadinova N, Mitreva-Staleva J, Grozdanov P, Stoynev A. Protective effects of losartan on some type 2 diabetes mellitus-induced complications in Wistar and spontaneously hypertensive rats. Metab Brain Dis 2020; 35:527-538. [PMID: 31997264 DOI: 10.1007/s11011-020-00534-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 01/17/2020] [Indexed: 01/13/2023]
Abstract
Diabetes mellitus type 2 (T2DM) is characterized by resistance of insulin receptors and/or inadequate insulin secretion resulting in metabolic and structural complications including vascular diseases, arterial hypertension and different behavioral alterations. We aimed to study the effects of the antihypertensive angiotensin AT1 receptor antagonist losartan on the T2DM-induced changes of exploratory behavior, anxiety, nociception and short term memory in normotensive Wistar and spontaneously hypertensive rats (SHRs). The experimental model of T2DM induced by a combination of high fat diet and streptozotocin, decreased exploratory activity and increased the level of carbonylated proteins in selected brain structures in both strains; as well it increased corticosterone level, pain threshold, anxiety-like behavior, and decline short term memory only in SHRs. Losartan treatment alleviated some of the T2DM- induced metabolic complications, abolished the T2DM-induced hypo activity, and normalized the corticosterone level, carbonylated proteins in brain, nociception and memory. Losartan did not exert effect on the anxiety behavior in both strains. We showed that T2DM exerted more pronounced negative effects on the rats with comorbid hypertension as compared to normotensive rats. Overall effects on the studied behavioral parameters are related to decreased exploration of the new environment, increased anxiety-like behavior, and decline in short-term memory. The systemic sub-chronic treatment with an angiotensin AT1 receptor antagonist losartan ameliorated most of these complications.
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Affiliation(s)
- Daniela Pechlivanova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria.
| | - Ekaterina Krumova
- Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria
| | - Nedelina Kostadinova
- Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria
| | - Jeny Mitreva-Staleva
- Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria
| | - Petar Grozdanov
- Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria
| | - Alexander Stoynev
- Department of Pathophysiology, Medical University-Sofia, St. Georgi Sofiyski Str. 1, 1431, Sofia, Bulgaria
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Stress-induced plasticity and functioning of ventral tegmental dopamine neurons. Neurosci Biobehav Rev 2020; 108:48-77. [DOI: 10.1016/j.neubiorev.2019.10.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/26/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022]
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Activation of the G Protein-Coupled Estrogen Receptor (GPER) Increases Neurogenesis and Ameliorates Neuroinflammation in the Hippocampus of Male Spontaneously Hypertensive Rats. Cell Mol Neurobiol 2019; 40:711-723. [DOI: 10.1007/s10571-019-00766-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/22/2019] [Indexed: 01/20/2023]
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Ivanova N, Tchekalarova J. The Potential Therapeutic Capacity of Inhibiting the Brain Renin-Angiotensin System in the Treatment of Co-Morbid Conditions in Epilepsy. CNS Drugs 2019; 33:1101-1112. [PMID: 31680223 DOI: 10.1007/s40263-019-00678-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Epilepsy is one of the most prevalent neurological diseases and although numerous novel anticonvulsants have been approved, the proportion of patients who are refractory to medical treatment of seizures and have progressive co-morbidities such as cognitive impairment and depression remains at about 20-30%. In the last decade, extensive research has identified a therapeutic capacity of the components of the brain renin-angiotensin system (RAS) in seizure- and epilepsy-related phenomena. Alleviating the activity of RAS in the central nervous system is considered to be a potential adjuvant strategy for the treatment of numerous detrimental consequences of epileptogenesis. One of the main advantages of RAS is associated with its modulatory influence on different neurotransmitter systems, thereby exerting a fine-tuning control mechanism for brain excitability. The most recent scientific findings regarding the involvement of the components of brain RAS show that angiotensin II (Ang II), angiotensin-converting enzyme (ACE), Ang II type 1 (AT1) and type 2 (AT2) receptors are involved in the control of epilepsy and its accompanying complications, and therefore they are currently of therapeutic interest in the treatment of this disease. However, data on the role of different components of brain RAS on co-morbid conditions in epilepsy, including hypertension, are insufficient. Experimental and clinical findings related to the involvement of Ang II, ACE, AT1, and AT2 receptors in the control of epilepsy and accompanying complications may point to new therapeutic opportunities and adjuvants for the treatment of common co-morbid conditions of epilepsy.
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Affiliation(s)
- Natasha Ivanova
- Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Acad. G. Bonchev Str., 1113, Sofia, Bulgaria.
| | - Jana Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Acad. G. Bonchev Str., 1113, Sofia, Bulgaria
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Hypertension and Its Impact on Stroke Recovery: From a Vascular to a Parenchymal Overview. Neural Plast 2019; 2019:6843895. [PMID: 31737062 PMCID: PMC6815533 DOI: 10.1155/2019/6843895] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Hypertension is the first modifiable vascular risk factor accounting for 10.4 million deaths worldwide; it is strongly and independently associated with the risk of stroke and is related to worse prognosis. In addition, hypertension seems to be a key player in the implementation of vascular cognitive impairment. Long-term hypertension, complicated or not by the occurrence of ischemic stroke, is often reviewed on its vascular side, and parenchymal consequences are put aside. Here, we sought to review the impact of isolated hypertension or hypertension associated to stroke on brain atrophy, neuron connectivity and neurogenesis, and phenotype modification of microglia and astrocytes. Finally, we discuss the impact of antihypertensive therapies on cell responses to hypertension and functional recovery. This attractive topic remains a focus of continued investigation and stresses the relevance of including this vascular risk factor in preclinical investigations of stroke outcome.
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Mineralocorticoid Receptors, Neuroinflammation and Hypertensive Encephalopathy. Cell Mol Neurobiol 2018; 39:483-492. [DOI: 10.1007/s10571-018-0610-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/06/2018] [Indexed: 02/07/2023]
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de Kloet ER, Meijer OC, de Nicola AF, de Rijk RH, Joëls M. Importance of the brain corticosteroid receptor balance in metaplasticity, cognitive performance and neuro-inflammation. Front Neuroendocrinol 2018; 49:124-145. [PMID: 29428549 DOI: 10.1016/j.yfrne.2018.02.003] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/25/2018] [Accepted: 02/07/2018] [Indexed: 01/14/2023]
Abstract
Bruce McEwen's discovery of receptors for corticosterone in the rat hippocampus introduced higher brain circuits in the neuroendocrinology of stress. Subsequently, these receptors were identified as mineralocorticoid receptors (MRs) that are involved in appraisal processes, choice of coping style, encoding and retrieval. The MR-mediated actions on cognition are complemented by slower actions via glucocorticoid receptors (GRs) on contextualization, rationalization and memory storage of the experience. These sequential phases in cognitive performance depend on synaptic metaplasticity that is regulated by coordinate MR- and GR activation. The receptor activation includes recruitment of coregulators and transcription factors as determinants of context-dependent specificity in steroid action; they can be modulated by genetic variation and (early) experience. Interestingly, inflammatory responses to damage seem to be governed by a similarly balanced MR:GR-mediated action as the initiating, terminating and priming mechanisms involved in stress-adaptation. We conclude with five questions challenging the MR:GR balance hypothesis.
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Affiliation(s)
- E R de Kloet
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands.
| | - O C Meijer
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands.
| | - A F de Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental, Buenos Aires, Argentina.
| | - R H de Rijk
- Department of Psychiatry, Leiden University Medical Center, Leiden, The Netherlands & Department of Clinical Psychology, Leiden University, The Netherlands.
| | - M Joëls
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands; University of Groningen, University Medical Center Groningen, The Netherlands.
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Bhat SA, Goel R, Shukla S, Shukla R, Hanif K. Angiotensin Receptor Blockade by Inhibiting Glial Activation Promotes Hippocampal Neurogenesis Via Activation of Wnt/β-Catenin Signaling in Hypertension. Mol Neurobiol 2017; 55:5282-5298. [DOI: 10.1007/s12035-017-0754-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 08/23/2017] [Indexed: 12/21/2022]
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12
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Pistikova A, Brozka H, Bencze M, Radostova D, Vales K, Stuchlik A. The effect of hypertension on adult hippocampal neurogenesis in young adult spontaneously hypertensive rats and Dahl rats. Physiol Res 2017; 66:881-887. [PMID: 28730828 DOI: 10.33549/physiolres.933562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The dentate gyrus of the hippocampus is one of the few places in the brain where neurogenesis occurs in adulthood. Nowadays, an increasing number of children and young adults are affected by hypertension, one of the factors in the development of cerebrovascular diseases and age-related cognitive deficits. Since these cognitive deficits are often hippocampus-dependent, it is possible that hypertension exerts this effect via decreasing adult neurogenesis which has been shown to be essential for a range of cognitive tasks. We used spontaneously hypertensive rats, which develop hypertension in the first weeks of life. Half of them were treated with the antihypertensive drug captopril. We found that the drug-induced lowering of blood pressure in this period did not affect the rate of adult neurogenesis. In a second experiment, we used another animal model of hypertension - salt-sensitive and salt-resistant strains of Dahl rats. A high-salt diet induces hypertension in the salt-sensitive strain, but not in the salt-resistant strain. The high-salt diet led to salt-induced hypertension, but did not affect the level of adult neurogenesis in the dentate gyrus of the hippocampus. We conclude that hypertension does not significantly affect the rate of hippocampal neurogenesis in young adult rats.
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Affiliation(s)
- A Pistikova
- Department of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic. or
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Brocca ME, Pietranera L, Meyer M, Lima A, Roig P, de Kloet ER, De Nicola AF. Mineralocorticoid receptor associates with pro-inflammatory bias in the hippocampus of spontaneously hypertensive rats. J Neuroendocrinol 2017; 29. [PMID: 28523794 DOI: 10.1111/jne.12489] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 12/20/2022]
Abstract
Damage observed in the hippocampus of the adult spontaneously hypertensive rat (SHR) resembles the neuropathology of mineralocorticoid-induced hypertension, supporting a similar endocrine dysfunction in both entities. In the present study, we tested the hypothesis that increased expression of the hippocampal mineralocorticoid receptor (MR) in SHR animals is associated with a prevalent expression of pro-inflammatory over anti-inflammatory factors. Accordingly, in the hippocampus, we measured mRNA expression and immunoreactivity of the MR and glucocorticoid receptor (GR) using a quantitative polymerase chain reaction and histochemistry. We also measured serum-glucocorticoid-activated kinase 1 (Sgk1 mRNA), the number and phenotype of Iba1+ microglia, as well as mRNA expression levels of the pro-inflammatory factors cyclo-oxygenase 2 (Cox2), Nlrp3 inflammasome and tumour necrosis factor α (Tnfα). Expression of anti-inflammatory transforming growth factor (Tgf)β mRNA and the NADPH-diaphorase activity of nitric oxide synthase (NOS) were also determined. The results showed that, in the hippocampus of SHR rats, expression of MR and the number of immunoreactive MR/GR co-expressing cells were increased compared to Wistar-Kyoto control animals. Expression of Sgk1, Cox2, Nlrp3 and the number of ramified glia cells positive for Iba1+ were also increased, whereas Tgfβ mRNA expression and the NADPH-diaphorase activity of NOS were decreased. We propose that, in the SHR hippocampus, increased MR expression causes a bias towards a pro-inflammatory phenotype characteristic for hypertensive encephalopathy.
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Affiliation(s)
- M E Brocca
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
| | - L Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
- Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - M Meyer
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
| | - A Lima
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
| | - P Roig
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
| | - E R de Kloet
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - A F De Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
- Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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Jure I, Pietranera L, De Nicola AF, Labombarda F. Spinal Cord Injury Impairs Neurogenesis and Induces Glial Reactivity in the Hippocampus. Neurochem Res 2017; 42:2178-2190. [DOI: 10.1007/s11064-017-2225-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 11/29/2022]
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Russo E, Leo A, Scicchitano F, Donato A, Ferlazzo E, Gasparini S, Cianci V, Mignogna C, Donato G, Citraro R, Aguglia U, De Sarro G. Cerebral small vessel disease predisposes to temporal lobe epilepsy in spontaneously hypertensive rats. Brain Res Bull 2017; 130:245-250. [PMID: 28214547 DOI: 10.1016/j.brainresbull.2017.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 01/30/2017] [Accepted: 02/13/2017] [Indexed: 01/13/2023]
Abstract
The link between cerebral small vessel disease (CSVD) and epilepsy has been poorly investigated. Some reports suggest that CSVD may predispose to temporal lobe epilepsy (TLE). Aim of this study was to evaluate whether spontaneously hypertensive rats (SHRs), an established model of systemic hypertension and CSVD, have a propensity to develop TLE more than generalized seizures. To this aim, amygdala kindling, as a model of TLE, and pentylenetetrazole (PTZ)-induced kindling, as a model of generalized seizures, have been used to ascertain whether SHRs are more prone to TLE as compared to Wistar Kyoto control rats. While young SHRs (without CSVD) do not differ from their age-matched controls in both models, old SHRs (with CSVD) develop stage 5 seizures in the amygdala kindling model (TLE) faster than age-matched control rats without CSVD. At odds, no differences between old SHRs and age-matched controls was observed in the development of PTZ kindling. Enalapril pre-treatment prevented the development of CSVD and normalized kindling development to control levels in SHRs. No difference was observed in the response to pharmacological treatment with carbamazepine or losartan. Overall, our study suggests that uncontrolled hypertension leading to CSVD might represent a risk factor for TLE. Further experimental studies are needed to unravel other risk factors that, along with CSVD, may predispose to TLE.
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Affiliation(s)
- Emilio Russo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy.
| | - Antonio Leo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Francesca Scicchitano
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Annalidia Donato
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Edoardo Ferlazzo
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Sara Gasparini
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Vittoria Cianci
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| | - Chiara Mignogna
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Giuseppe Donato
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Umberto Aguglia
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
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Hippocampal neurogenesis response: What can we expect from two different models of hypertension? Brain Res 2016; 1646:199-206. [DOI: 10.1016/j.brainres.2016.05.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/11/2016] [Accepted: 05/24/2016] [Indexed: 01/17/2023]
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17
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Comparative power spectrum analysis of EEG activity in spontaneously hypertensive and Wistar rats in kainate model of temporal model of epilepsy. Brain Res Bull 2016; 124:62-75. [DOI: 10.1016/j.brainresbull.2016.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/23/2016] [Accepted: 03/30/2016] [Indexed: 11/23/2022]
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Shih YH, Tsai SF, Huang SH, Chiang YT, Hughes MW, Wu SY, Lee CW, Yang TT, Kuo YM. Hypertension impairs hippocampus-related adult neurogenesis, CA1 neuron dendritic arborization and long-term memory. Neuroscience 2016; 322:346-57. [PMID: 26921651 DOI: 10.1016/j.neuroscience.2016.02.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/02/2016] [Accepted: 02/18/2016] [Indexed: 02/07/2023]
Abstract
Hypertension is associated with neurodegenerative diseases and cognitive impairment. Several studies using spontaneous hypertensive rats to study the effect of hypertension on memory performance and adult hippocampal neurogenesis have reached inconsistent conclusions. The contradictory findings may be related to the genetic variability of spontaneous hypertensive rats due to the conventional breeding practices. The objective of this study is to examine the effect of hypertension on hippocampal structure and function in isogenic mice. Hypertension was induced by the '2 kidneys, 1 clip' method (2K1C) which constricted one of the two renal arteries. The blood pressures of 2K1C mice were higher than the sham group on post-operation day 7 and remained high up to day 28. Mice with 2K1C-induced hypertension had impaired long-term, but not short-term, memory. Dendritic complexity of CA1 neurons and hippocampal neurogenesis were reduced by 2K1C-induced hypertension on post-operation day 28. Furthermore, 2K1C decreased the levels of hippocampal brain-derived neurotrophic factor, while blood vessel density and activation status of astrocytes and microglia were not affected. In conclusion, hypertension impairs hippocampus-associated long-term memory, dendritic arborization and neurogenesis, which may be caused by down-regulation of brain-derived neurotrophic factor signaling pathways.
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Affiliation(s)
- Y-H Shih
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - S-F Tsai
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - S-H Huang
- Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, Taiwan
| | - Y-T Chiang
- Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, Taiwan
| | - M W Hughes
- International Research Center of Wound Repair & Regeneration, Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan
| | - S-Y Wu
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - C-W Lee
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
| | - T-T Yang
- Department of Chinese Medicine for Post-Baccalaureate, I-Shou University, Kaohsiung, Taiwan
| | - Y-M Kuo
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan; Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, Taiwan.
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Tchekalarova J, Shishmanova M, Atanasova D, Stefanova M, Alova L, Lazarov N, Georgieva K. Effect of endurance training on seizure susceptibility, behavioral changes and neuronal damage after kainate-induced status epilepticus in spontaneously hypertensive rats. Brain Res 2015; 1625:39-53. [PMID: 26319691 DOI: 10.1016/j.brainres.2015.08.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/28/2015] [Accepted: 08/05/2015] [Indexed: 02/02/2023]
Abstract
The therapeutic efficacy of regular physical exercises in an animal model of epilepsy and depression comorbidity has been confirmed previously. In the present study, we examined the effects of endurance training on susceptibility to kainate (KA)-induced status epilepticus (SE), behavioral changes and neuronal damage in spontaneously hypertensive rats (SHRs). Male SHRs were randomly divided into two groups. One group was exercised on a treadmill with submaximal loading for four weeks and the other group was sedentary. Immediately after the training period, SE was evoked in half of the sedentary and trained rats by KA, while the other half of the two groups received saline. Basal systolic (SP), diastolic (DP) and mean arterial pressure (MAP) of all rats were measured at the beginning and at the end of the training period. Anxiety, memory and depression-like behaviour were evaluated a month after SE. The release of 5-HT in the hippocampus was measured using a liquid scintillation method and neuronal damage was analyzed by hematoxylin and eosin staining. SP and MAP of exercised SHRs decreased in comparison with the initial values. The increased resistance of SHRs to KA-induced SE was accompanied by an elongated latent seizure-free period, improved object recognition memory and antidepressant effect after the training program. While the anticonvulsant and positive behavioral effects of endurance training were accompanied by an increase of 5-HT release in the hippocampus, it did not exert neuroprotective activity. Our results indicate that prior exercise is an effective means to attenuate KA-induced seizures and comorbid behavioral changes in a model of hypertension and epilepsy suggesting a potential influence of hippocampal 5-HT on a comorbid depression. However, this beneficial impact does not prevent the development of epilepsy and concomitant brain damage.
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Affiliation(s)
- J Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Bulgaria.
| | - M Shishmanova
- Department of Pharmacology and Drug Toxicology, Medical University - Plovdiv, Bulgaria
| | - D Atanasova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Bulgaria
| | - M Stefanova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Bulgaria
| | - L Alova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Bulgaria
| | - N Lazarov
- Department of Anatomy, Medical University - Sofia, Bulgaria
| | - K Georgieva
- Department of Physiology, Medical University - Plovdiv, Bulgaria
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Tchekalarova J, Loyens E, Smolders I. Effects of AT1 receptor antagonism on kainate-induced seizures and concomitant changes in hippocampal extracellular noradrenaline, serotonin, and dopamine levels in Wistar-Kyoto and spontaneously hypertensive rats. Epilepsy Behav 2015; 46:66-71. [PMID: 25922088 DOI: 10.1016/j.yebeh.2015.03.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 03/20/2015] [Accepted: 03/21/2015] [Indexed: 12/14/2022]
Abstract
In the management of epilepsy, AT1 receptor antagonists have been suggested as an additional treatment strategy. A hyperactive brain angiotensin (Ang) II system and upregulated AT1 receptors are implicated in the cerebrovascular alterations in a genetic form of hypertension. Uncontrolled hypertension could also, in turn, be a risk factor for a seizure threshold decrease and development of epileptogenesis. The present study aimed to assess the effects of the selective AT1 receptor antagonist ZD7155 on kainic acid (KA)-induced status epilepticus (SE) development and accompanying changes in the hippocampal extracellular (EC) neurotransmitter levels of noradrenaline (NAD), serotonin (5-HT), and dopamine (DA) in spontaneously hypertensive rats (SHRs) and their parent strain Wistar-Kyoto (WKY) rats, since monoamines are well-known neurotransmitters involved in mechanisms of both epilepsy and hypertension. Status epilepticus was evoked in freely moving rats by a repetitive intraperitoneal (i.p.) administration of KA in subconvulsant doses. In the treatment group, ZD7155 (5mg/kg i.p.) was coadministered with the first KA injection. Spontaneously hypertensive rats exhibited higher susceptibility to SE than WKY rats, but the AT1 receptor antagonist did not alter the development of SE in SHRs or in WKY rats. In vivo microdialysis demonstrated significant KA-induced increases of the hippocampal NAD and DA levels in SHRs and of NAD, 5-HT, and DA in WKY rats. Although SHRs developed more severe seizures while receiving a lower dose of KA compared to WKY rats, AT1 receptor antagonism completely prevented all KA-induced increases of hippocampal monoamine levels in both rat strains without affecting seizure development per se. These results suggest a lack of direct relationship between KA-induced seizure susceptibility and adaptive changes of hippocampal NAD, 5-HT, and DA levels in the effects of ZD7155 in WKY rats and SHRs.
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Affiliation(s)
- Jana Tchekalarova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
| | - Ellen Loyens
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
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Pietranera L, Brocca ME, Roig P, Lima A, Garcia-Segura LM, De Nicola AF. Estrogens are neuroprotective factors for hypertensive encephalopathy. J Steroid Biochem Mol Biol 2015; 146:15-25. [PMID: 24736028 DOI: 10.1016/j.jsbmb.2014.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/04/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
Abstract
Estrogens are neuroprotective factors for brain diseases, including hypertensive encephalopathy. In particular, the hippocampus is highly damaged by high blood pressure, with several hippocampus functions being altered in humans and animal models of hypertension. Working with a genetic model of primary hypertension, the spontaneously hypertensive rat (SHR), we have shown that SHR present decreased dentate gyrus neurogenesis, astrogliosis, low expression of brain derived neurotrophic factor (BDNF), decreased number of neurons in the hilus of the dentate gyrus, increased basal levels of the estrogen-synthesizing enzyme aromatase, and atrophic dendritic arbor with low spine density in the CA1 region compared to normotensive Wistar Kyoto (WKY) ratsl. Changes also occur in the hypothalamus of SHR, with increased expression of the hypertensinogenic peptide arginine vasopressin (AVP) and its V1b receptor. Following chronic estradiol treatment, SHR show decreased blood pressure, enhanced hippocampus neurogenesis, decreased the reactive astrogliosis, increased BDNF mRNA and protein expression in the dentate gyrus, increased neuronal number in the hilus of the dentate gyrus, further increased the hyperexpression of aromatase and replaced spine number with remodeling of the dendritic arbor of the CA1 region. We have detected by qPCR the estradiol receptors ERα and ERβ in hippocampus from both SHR and WKY rats, suggesting direct effects of estradiol on brain cells. We hypothesize that a combination of exogenously given estrogens plus those locally synthesized by estradiol-stimulated aromatase may better alleviate the hippocampal and hypothalamic encephalopathy of SHR. This article is part of a Special Issue entitled "Sex steroids and brain disorders".
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Affiliation(s)
- Luciana Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428 Buenos Aires, Argentina; Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Paraguay 2155, 1425 Buenos Aires, Argentina
| | - Maria Elvira Brocca
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Paulina Roig
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Analia Lima
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas, Avenida Doctor Arce 37, E-28002 Madrid, Spain
| | - Alejandro F De Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Obligado 2490, 1428 Buenos Aires, Argentina; Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Paraguay 2155, 1425 Buenos Aires, Argentina.
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Brocca M, Pietranera L, Roig P, Lima A, De Nicola A. Effects of 17β-estradiol on the cytoarchitecture of pyramidal CA1 neurons in normoglycemic and diabetic male spontaneously hypertensive rats. Neuroscience 2014; 280:243-53. [DOI: 10.1016/j.neuroscience.2014.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/25/2014] [Accepted: 09/11/2014] [Indexed: 12/20/2022]
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Pietranera L, Brocca ME, Roig P, Lima A, Garcia-Segura LM, De Nicola AF. 17α-Oestradiol-induced neuroprotection in the brain of spontaneously hypertensive rats. J Neuroendocrinol 2014; 26:310-20. [PMID: 24730417 DOI: 10.1111/jne.12151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/20/2014] [Accepted: 03/16/2014] [Indexed: 11/27/2022]
Abstract
17β-oestradiol is a powerful neuroprotective factor for the brain abnormalities of spontaneously hypertensive rats (SHR). 17α-Oestradiol, a nonfeminising isomer showing low affinity for oestrogen receptors, is also endowed with neuroprotective effects in vivo and in vitro. We therefore investigated whether treatment with 17α-oestradiol prevented pathological changes of the hippocampus and hypothalamus of SHR. We used 20-week-old male SHR with a blood pressure of approximately 170 mmHg receiving s.c. a single 800 μg pellet of 17α-oestradiol dissolved in cholesterol or vehicle only for 2 weeks Normotensive Wistar-Kyoto (WKY) rats were used as controls. 17α-Oestradiol did not modify blood pressure, serum prolactin, 17β-oestradiol levels or the weight of the testis and pituitary of SHR. In the brain, we analysed steroid effects on hippocampus Ki67+ proliferating cells, doublecortin (DCX) positive neuroblasts, glial fibrillary acidic protein (GFAP)+ astrocyte density, aromatase immunostaining and brain-derived neurotrophic factor (BDNF) mRNA. In the hypothalamus, we determined arginine vasopressin (AVP) mRNA. Treatment of SHR with 17α-oestradiol enhanced the number of Ki67+ in the subgranular zone and DCX+ cells in the inner granule cell layer of the dentate gyrus, increased BDNF mRNA in the CA1 region and gyrus dentatus, decreased GFAP+ astrogliosis in the CA1 subfield, and decreased hypothalamic AVP mRNA. Aromatase expression was unmodified. By contrast to SHR, normotensive WKY rats were unresponsive to 17α-oestradiol. These data indicate a role for 17α-oestradiol as a protective factor for the treatment of hypertensive encephalopathy. Furthermore, 17α-oestradiol is weakly oestrogenic in the periphery and can be used in males.
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Affiliation(s)
- L Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina; Department of Human Biochemistry, Faculty of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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Petkova Z, Tchekalarova J, Pechlivanova D, Moyanova S, Kortenska L, Mitreva R, Popov D, Markova P, Lozanov V, Atanasova D, Lazarov N, Stoynev A. Treatment with melatonin after status epilepticus attenuates seizure activity and neuronal damage but does not prevent the disturbance in diurnal rhythms and behavioral alterations in spontaneously hypertensive rats in kainate model of temporal lobe epilepsy. Epilepsy Behav 2014; 31:198-208. [PMID: 24440891 DOI: 10.1016/j.yebeh.2013.12.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/14/2013] [Accepted: 12/15/2013] [Indexed: 11/16/2022]
Abstract
Melatonin is involved in the control of circadian and seasonal rhythmicity, possesses potent antioxidant activity, and exerts a neuroprotective and anticonvulsant effect. Spontaneously hypertensive rats (SHRs) are widely accepted as an experimental model of essential hypertension with hyperactivity, deficient sustained attention, and alterations in circadian autonomic profiles. The purpose of the present study was to determine whether melatonin treatment during epileptogenesis can prevent the deleterious consequences of status epilepticus (SE) in SHRs in the kainate (KA) model of temporal lobe of epilepsy (TLE). Spontaneous recurrent seizures (SRSs) were EEG- and video-recorded during and after the treatment protocol. Melatonin (10mg/kg diluted in drinking water, 8weeks) increased the seizure-latent period, decreased the frequency of SRSs, and attenuated the circadian rhythm of seizure activity in SHRs. However, melatonin was unable to affect the disturbed diurnal rhythms and behavioral changes associated with epilepsy, including the decreased anxiety level, depression, and impaired spatial memory. Melatonin reduced neuronal damage specifically in the CA1 area of the hippocampus and piriform cortex and decreased hippocampal serotonin (5-HT) levels both in control and epileptic SHRs. Although long-term melatonin treatment after SE shows a potential to attenuate seizure activity and neuronal loss, it is unable to restore epilepsy-associated behavioral abnormalities in SHRs.
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Affiliation(s)
- Zlatina Petkova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Jana Tchekalarova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
| | - Daniela Pechlivanova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Slavianka Moyanova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Lidia Kortenska
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Rumiana Mitreva
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Deyan Popov
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Petya Markova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Valentin Lozanov
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Dimitrina Atanasova
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Nikolai Lazarov
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Alexander Stoynev
- Institute of Neurobiology, Acad. G. Bonchev Str., Bl. 23, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
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Atanasova M, Petkova Z, Pechlivanova D, Dragomirova P, Blazhev A, Tchekalarova J. Strain-dependent effects of long-term treatment with melatonin on kainic acid-induced status epilepticus, oxidative stress and the expression of heat shock proteins. Pharmacol Biochem Behav 2013; 111:44-50. [DOI: 10.1016/j.pbb.2013.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/10/2013] [Accepted: 08/14/2013] [Indexed: 11/28/2022]
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26
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Daulatzai MA. Neurotoxic Saboteurs: Straws that Break the Hippo’s (Hippocampus) Back Drive Cognitive Impairment and Alzheimer’s Disease. Neurotox Res 2013; 24:407-59. [DOI: 10.1007/s12640-013-9407-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/06/2013] [Accepted: 06/17/2013] [Indexed: 12/29/2022]
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Brocca ME, Pietranera L, Beauquis J, De Nicola AF. Estradiol increases dendritic length and spine density in CA1 neurons of the hippocampus of spontaneously hypertensive rats: a Golgi impregnation study. Exp Neurol 2013; 247:158-64. [PMID: 23628746 DOI: 10.1016/j.expneurol.2013.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/20/2013] [Accepted: 04/12/2013] [Indexed: 02/06/2023]
Abstract
Increased neuronal vulnerability has been described in the brain of spontaneously hypertensive rats (SHR), models of primary hypertension. Previous data indicate that estradiol treatment corrects several dysfunctions of the hippocampus and hypothalamus of SHR. Considering this evidence we analyzed the dendritic arborization and spine density of the CA1 subfield in SHR and Wistar-Kyoto (WKY) normotensive rats with and without estradiol treatment. Five month old male SHR and WKY rats received single estradiol or cholesterol pellets (sham treatment) for 2 weeks. A substantial rise of circulating estradiol (>25 fold) and testicular atrophy was present in all estradiol-receiving rats. In both SHR and WKY rats, estradiol decreased blood pressure by ~20 mm Hg; however, a moderate hypertension persisted in SHR (164 mm Hg). Using a modified Golgi impregnation technique, apical and basal dendrites of the CA1 subfield were subjected to Sholl analysis. Spine density was also statistically analyzed. Apical dendritic length was significantly lower in SHR compared to WKY rats (p<0.01), whereas estradiol treatment increased dendritic length in the SHR group only (SHR vs SHR+estradiol; p<0.01). Apical dendritic length plotted against the shell distances 20-100, 120-200 and 220-300 μm, revealed that changes were more pronounced in the range 120-200 μm between SHR vs. WKY rats (p<0.05) and SHR vs. SHR+estradiol (p<0.05). Instead, basal dendrites were not significantly modified by hypertension or steroid treatment. Spine density of apical dendrites was lower in SHR than WKY (p<0.05) and was up-regulated in the SHR+estradiol group compared to the SHR group (p<0.001). Similar changes were obtained for basal dendritic spines. These data suggest that changes of neuronal processes in SHR are plastic events restorable by estradiol treatment. In conjunction with previous results, the present data reveal new targets of estradiol neuroprotection in the brain of hypertensive rats.
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Affiliation(s)
- María Elvira Brocca
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental, Argentina
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28
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Pietranera L, Brocca ME, Cymeryng C, Gomez-Sanchez E, Gomez-Sanchez CE, Roig P, Lima A, De Nicola AF. Increased expression of the mineralocorticoid receptor in the brain of spontaneously hypertensive rats. J Neuroendocrinol 2012; 24:1249-58. [PMID: 22564091 DOI: 10.1111/j.1365-2826.2012.02332.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mineralocorticoid receptor (MR) has been considered as both neuroprotective and damaging to the function of the central nervous system. MR may be also involved in central regulation of blood pressure. In the present study, we compared the expression of MR and the glucocorticoid receptor (GR) in the hippocampus and hypothalamus of 16-week-old spontaneously hypertensive rats (SHR) and normotensive control Wistar Kyoto (WKY) rats. In the hippocampus, MR expression was studied by in situ hybridization (ISH), quantitative polymerase chain reaction (PCR) and immunohistochemistry, whereas GR expression was analysed using the latter two procedures. Hypertensive animals showed an increased expression of MR mRNA in the whole hippocampus according to qPCR data and also in CA3 by ISH. Immunocytochemical staining for MR of the dorsal hippocampus, however, did not reveal differences between SHR and WKY rats. SHR showed elevated hypothalamic MR mRNA by qPCR, as well as an increased number of MR immunopositive cells in the magnocellular paraventricular region, compared to WKY rats. By contrast, expression levels of GR mRNA or protein in the hippocampus and hypothalamus of SHR were similar to those of WKY rats. Furthermore, we investigated the role of MR in the hypertensive rats by i.c.v. injection of the MR antagonist RU-2831. This compound produced a significant drop in blood pressure for SHR. In conclusion, MR expression is increased in the hippocampus and hypothalamus of SHR. We suggest that pathological MR overdrive may take responsibility for up-regulation of blood pressure and the encephalopathy of hypertension.
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Affiliation(s)
- L Pietranera
- Institute of Biology and Experimental Medicine, CONICET, Obligado, Buenos Aires, Argentina
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29
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Pietranera L, Bellini M, Arévalo M, Goya R, Brocca M, Garcia-Segura L, De Nicola A. Increased aromatase expression in the hippocampus of spontaneously hypertensive rats: effects of estradiol administration. Neuroscience 2011; 174:151-9. [DOI: 10.1016/j.neuroscience.2010.11.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 11/04/2010] [Accepted: 11/20/2010] [Indexed: 12/26/2022]
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Tchekalarova J, Pechlivanova D, Atanasova T, Markova P, Lozanov V, Stoynev A. Diurnal variations in depression-like behavior of Wistar and spontaneously hypertensive rats in the kainate model of temporal lobe epilepsy. Epilepsy Behav 2011; 20:277-85. [PMID: 21277833 DOI: 10.1016/j.yebeh.2010.12.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to explore whether the kainate (KA) model of temporal lobe epilepsy (TLE) can be used as a model of comorbid epilepsy and depression to study diurnal behavioral variations in rats. Development of chronic epilepsy was confirmed by the detection of spontaneous motor seizures (SMS) with video monitoring (24 hours/3-5 months after status epilepticus [SE]). KA-treated spontaneously hypertensive rats (SHRs) exhibited higher seizure frequency than Wistar rats during the light phase in the fourth and fifth months after SE. Although epileptic Wistar rats showed depression-like behavior and reduced anxiety mostly during the light phase, there were no diurnal variations in depression-like patterns in SHRs. Anxiety levels of control and epileptic SHRs were similar. Decreases in serotonin, tryptophan, and dopamine concentrations in the hippocampus were detected in epileptic Wistar rats compared with naive controls. However, monoamine levels of epileptic SHRs were close to those of their controls. Wistar rats and SHRs develop stable depression-like behavior during the chronic epileptic phase with strain-dependent diurnal differences.
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Affiliation(s)
- Jana Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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De Nicola AF, Pietranera L, Bellini MJ, Goya R, Brocca ME, Garcia-Segura LM. Protective effect of estrogens on the brain of rats with essential and endocrine hypertension. Horm Mol Biol Clin Investig 2010; 4:549-57. [PMID: 25961231 DOI: 10.1515/hmbci.2010.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 09/02/2010] [Indexed: 11/15/2022]
Abstract
Estrogen neuroprotection has been shown in pathological conditions damaging the hippocampus, such as trauma, aging, neurodegeneration, excitotoxicity, oxidative stress, hypoglycemia, amyloid-β peptide exposure and ischemia. Hypertensive encephalopathy also targets the hippocampus; therefore, hypertension seems an appropriate circumstance to evaluate steroid neuroprotection. Two experimental models of hypertension, spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats, develop hippocampal abnormalities, which include decreased neurogenesis in the dentate gyrus, astrogliosis, low expression of brain-derived neurotrophic factor (BDNF) and decreased number of neurons in the hilar region, with respect of their normotensive strains Wistar Kyoto (WKY) and Sprague-Dawley rats. After estradiol was given for 2 weeks to SHR and DOCA-treated rats, both hypertensive models normalized their faulty hippocampal parameters. Thus, estradiol treatment positively modulated neurogenesis in the dentate gyrus of the hippocampus, according to bromodeoxyuridine incorporation and doublecortin immunocytochemistry, decreased reactive astrogliosis, increased BDNF mRNA and protein expression in the dentate gyrus and increased neuronal number in the hilar region of the dentate gyrus. A role of local estrogen biosynthesis is suggested in SHR, because basal aromatase mRNA in the hippocampus and immunoreactive aromatase protein in cell processes of the dentate gyrus were highly expressed in these rats. Estradiol further stimulated aromatase-related parameters in SHR but not in WKY. These observations strongly support that a combination of exogenous estrogens to those locally synthesized might better alleviate hypertensive encephalopathy. These studies broaden estrogen neuroprotective functions to the hippocampus of hypertensive rat models.
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Pietranera L, Lima A, Roig P, De Nicola AF. Involvement of brain-derived neurotrophic factor and neurogenesis in oestradiol neuroprotection of the hippocampus of hypertensive rats. J Neuroendocrinol 2010; 22:1082-92. [PMID: 20722975 DOI: 10.1111/j.1365-2826.2010.02058.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The hippocampus of spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats shows decreased cell proliferation and astrogliosis as well as a reduced number of hilar cells. These defects are corrected after administration of 17β-oestradiol (E(2) ) for 2 weeks. The present work investigated whether E(2) treatment of SHR and of hypertensive DOCA-salt male rats modulated the expression of brain-derived neurotrophic factor (BDNF), a neurotrophin involved in hippocampal neurogenesis. The neurogenic response to E(2) was simultaneously determined by counting the number of doublecortin-immunopositive immature neurones in the subgranular zone of the dentate gyrus. Both hypertensive models showed decreased expression of BDNF mRNA in the granular zone of the dentate gyrus, without changes in CA1 or CA3 pyramidal cell layers, decreased BDNF protein levels in whole hippocampal tissue, low density of doublecortin (DCX)-positive immature neurones in the subgranule zone and decreased length of DCX+ neurites in the dentate gyrus. After s.c. implantation of a single E(2) pellet for 2 weeks, BDNF mRNA in the dentate gyrus, BDNF protein in whole hippocampus, DCX immunopositive cells and the length of DCX+ neurites were significantly raised in both SHR and DOCA-salt-treated rats. These results indicate that: (i) low BDNF expression and deficient neurogenesis distinguished the hippocampus of SHR and DOCA-salt hypertensive rats and (ii) E(2) was able to normalise these biologically important functions in the hippocampus of hypertensive animals.
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Affiliation(s)
- L Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Buenos Aires, Argentina
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Morris MJ, Na ES, Johnson AK. Mineralocorticoid receptor antagonism prevents hedonic deficits induced by a chronic sodium appetite. Behav Neurosci 2010; 124:211-24. [PMID: 20364881 DOI: 10.1037/a0018910] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Our laboratory has reported that manipulations that provoke a robust sodium appetite (e.g., sodium depletion, deoxycorticosterone acetate) decrease lateral hypothalamic self-stimulation (LHSS) reward if rats are denied access to hypertonic saline solutions. The following studies investigated the interaction between chronic sodium appetite and the renin-angiotensin-aldosterone system on LHSS reward. In Experiment 1, animals treated with the diuretic furosemide (20 mg/kg) when denied access to saline exhibited an increase in the current required to produce 50% of the maximum LHSS response rate (ECu50) 48 hr after extracellular volume depletion. Furosemide-depleted rats that were allowed to drink 0.3 M saline after depletion, or that were treated with the selective mineralocorticoid receptor (MR) antagonist spironolactone, which significantly reduced sodium appetite, did not show ECu50 changes. In Experiment 2 chronic intracerebroventricular administration of the selective MR antagonist RU 28318 (10 microg/microl/hr) prevented decreases in the ECu50 induced by deoxycorticosterone acetate-no salt treatment. We conclude that an unresolved sodium appetite will reduce responding for rewards and that experimental manipulations that reduce sodium appetite (e.g., access to saline or blockade of MR) decrease hedonic deficits.
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Affiliation(s)
- Michael J Morris
- Department of Psychology, Integrative Physiology and Pharmacology, and the Cardiovascular Center, The University of Iowa, Iowa City, IA 52242-1407, USA
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Biancardi VC, Campos RR, Stern JE. Altered balance of gamma-aminobutyric acidergic and glutamatergic afferent inputs in rostral ventrolateral medulla-projecting neurons in the paraventricular nucleus of the hypothalamus of renovascular hypertensive rats. J Comp Neurol 2010; 518:567-85. [PMID: 20034060 DOI: 10.1002/cne.22256] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An imbalance of excitatory and inhibitory functions has been shown to contribute to numerous pathological disorders. Accumulating evidence supports the idea that a change in hypothalamic gamma-aminobutyric acid (GABA)-ergic inhibitory and glutamatergic excitatory synaptic functions contributes to exacerbated neurohumoral drive in prevalent cardiovascular disorders, including hypertension. However, the precise underlying mechanisms and neuronal substrates are still not fully elucidated. In the present study, we combined quantitative immunohistochemistry with neuronal tract tracing to determine whether plastic remodeling of afferent GABAergic and glutamatergic inputs into identified RVLM-projecting neurons of the hypothalamic paraventricular nucleus (PVN-RVLM) contributes to an imbalanced excitatory/inhibitory function in renovascular hypertensive rats (RVH). Our results indicate that both GABAergic and glutamatergic innervation densities increased in oxytocin-positive, PVN-RVLM (OT-PVN-RVLM) neurons in RVH rats. Despite this concomitant increase, time-dependent and compartment-specific differences in the reorganization of these inputs resulted in an altered balance of excitatory/inhibitory inputs in somatic and dendritic compartments. A net predominance of excitatory over inhibitory inputs was found in OT-PVN-RVLM proximal dendrites. Our results indicate that, along with previously described changes in neurotransmitter release probability and postsynaptic receptor function, remodeling of GABAergic and glutamatergic afferent inputs contributes as an underlying mechanism to the altered excitatory/inhibitory balance in the PVN of hypertensive rats.
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Tchekalarova J, Pechlivanova D, Itzev D, Lazarov N, Markova P, Stoynev A. Diurnal rhythms of spontaneous recurrent seizures and behavioral alterations of Wistar and spontaneously hypertensive rats in the kainate model of epilepsy. Epilepsy Behav 2010; 17:23-32. [PMID: 20006556 DOI: 10.1016/j.yebeh.2009.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/02/2009] [Accepted: 11/03/2009] [Indexed: 10/20/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) can coexist with epilepsy. Spontaneously hypertensive rats (SHRs) are considered to model ADHD with overactivity, impulsiveness, deficient sustained attention, and alterations in circadian autonomic profiles. The present study explored spontaneous recurrent seizures (SRSs) and behavioral diurnal activity rhythms in normotensive Wistar rats and SHRs in the kainate model of epilepsy. Rats were video monitored (24 h/3 months) to detect SRSs. SHRs manifested a lower seizure frequency during the light phase in the 8th and 10th weeks and a lower frequency of SRSs during the night phase accompanied by attenuated responses in hyperexcitability tests. Both epileptic strains were hyperactive, with lower anxiety levels, and their diurnal rhythms were abolished. Epileptic Wistar rats and SHRs exhibited less exploration during the dark phase. This study suggests that SHRs may be useful in modeling some aspects (particularly hypertension-related diurnal rhythm disturbance) of behavior associated with epilepsy.
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Affiliation(s)
- Jane Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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Morris MJ, Na ES, Johnson AK. Salt craving: the psychobiology of pathogenic sodium intake. Physiol Behav 2008; 94:709-21. [PMID: 18514747 PMCID: PMC2491403 DOI: 10.1016/j.physbeh.2008.04.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 04/02/2008] [Indexed: 01/22/2023]
Abstract
Ionic sodium, obtained from dietary sources usually in the form of sodium chloride (NaCl, common table salt) is essential to physiological function, and in humans salt is generally regarded as highly palatable. This marriage of pleasant taste and physiological utility might appear fortunate--an appealing taste helps to ensure that such a vital substance is ingested. However, the powerful mechanisms governing sodium retention and sodium balance are unfortunately best adapted for an environment in which few humans still exist. Our physiological and behavioral means for maintaining body sodium and fluid homeostasis evolved in hot climates where sources of dietary sodium were scarce. For many reasons, contemporary diets are high in salt and daily sodium intakes are excessive. High sodium consumption can have pathological consequences. Although there are a number of obstacles to limiting salt ingestion, high sodium intake, like smoking, is a modifiable behavioral risk factor for many cardiovascular diseases. This review discusses the psychobiological mechanisms that promote and maintain excessive dietary sodium intake. Of particular importance are experience-dependent processes including the sensitization of the neural systems underlying sodium appetite and the effects of sodium balance on hedonic state and mood. Accumulating evidence suggests that plasticity within the central nervous system as a result of experience with high salt intake, sodium depletion, or a chronic unresolved sodium appetite fosters enduring changes in sodium related appetitive and consummatory behaviors.
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Affiliation(s)
- Michael J Morris
- Department of Psychology, The University of Iowa, Iowa City, IA, 52242-1407, USA
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Pietranera L, Saravia FE, Roig P, Lima A, De Nicola AF. Protective effects of estradiol in the brain of rats with genetic or mineralocorticoid-induced hypertension. Psychoneuroendocrinology 2008; 33:270-81. [PMID: 18164826 DOI: 10.1016/j.psyneuen.2007.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 11/12/2007] [Accepted: 11/19/2007] [Indexed: 12/15/2022]
Abstract
Abnormalities of hippocampus and hypothalamus are commonly observed in rats with genetic (SHR) or mineralocorticoid/salt-induced hypertension. In the hippocampus, changes include decreased cell proliferation in the dentate gyrus (DG), astrogliosis and decreased neuronal density in the hilus, whereas in the hypothalamus expression of arginine vasopressin (AVP) is markedly elevated. Here, we report that estradiol treatment overturns these abnormalities. We used 16-week-old male SHR with blood pressure (BP) approximately 190 mmHg and their normotensive Wistar-Kyoto (WKY) controls, and male Sprague-Dawley rats made hypertensive by administration of 10mg deoxycorticosterone acetate (DOCA) every other day plus 1% NaCl as drinking fluid for 4 weeks (BP approximately 160 mmHg). Controls received oil vehicle plus 1% NaCl only. Half of the animals in each group were implanted s.c. with a single estradiol benzoate pellet weighing 14 mg for 2 weeks. Estradiol-treated SHR and DOCA-salt rats showed, in comparison to their respective steroid-free groups: (a) enhanced proliferation in the DG measured by bromodeoxyuridine incorporation; (b) decreased number of glial fibrillary acidic protein (GFAP) immunopositive astrocytes; (c) increased density of neurons in the hilus of the DG, and (d) decreased hypothalamic AVP mRNA expression. These results indicate that neuronal and glial alterations of hypertensive models are plastic events reversible by steroid treatment. The estradiol protective effects may be of pharmacological interest to attenuate the consequences of hypertensive encephalopathy.
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Affiliation(s)
- Luciana Pietranera
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental, Buenos Aires, Argentina
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De Nicola AF, Pietranera L, Beauquis J, Ferrini MG, Saravia FE. Steroid protection in aging and age-associated diseases. Exp Gerontol 2008; 44:34-40. [PMID: 18445514 DOI: 10.1016/j.exger.2008.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 03/08/2008] [Accepted: 03/10/2008] [Indexed: 11/26/2022]
Abstract
Neuroactive steroids are secretory products of peripheral endocrine glands that modulate a variety of brain functions. A close relationship between neuroactive steroid structure and function becomes most evident under pathological circumstances. On one side, overproduction of glucocorticoid and mineralocorticoid neuroactive steroids may be detrimental to the hippocampus, which is enriched in glucocorticoid receptors (GR) and mineralocorticoid receptors (MR). Thus, a dysfunction of the adrenocortical system in aging and age-associated diseases (diabetes, hypertension) is able to cause hippocampal damage. Whereas aging and uncontrolled diabetes show a predominant GR overdrive, a MR overdrive characterizes hypertensive animals. Some abnormalities commonly found in the hippocampus of aging, diabetic and hypertensive animals include decreased neurogenesis, astrogliosis and neuronal loss in the hilus of the dentate gyrus (DG). On the other side, and in contrast to adrenal gland-derived steroids, estrogens qualify as hippocampal neuroprotectants. Given to middle-age mice, estrogens stimulated proliferation and differentiation of newborn cells in the DG, decreased astrogliosis and increased hilar neuronal number. Similar estrogen effects were obtained in mice with streptozotocin-induced diabetes and in spontaneously hypertensive rats (SHR). The results suggest that in aging and age-associated diseases, adrenocortical steroid overdrive sensitizes the hippocampus to the pathological milieu imposed by a pre-existing degeneration or illness. In this setting, estradiol neuroprotection rescues hippocampal parameters previously altered by the pathological environment.
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Affiliation(s)
- Alejandro F De Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental, Department of Human Biochemistry, Obligado 2490, 1428 Buenos Aires, Argentina.
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Bibliography. Current world literature. Adrenal cortex. Curr Opin Endocrinol Diabetes Obes 2007; 14:255-9. [PMID: 17940448 DOI: 10.1097/med.0b013e3281de7489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Siwak-Tapp CT, Head E, Muggenburg BA, Milgram NW, Cotman CW. Region specific neuron loss in the aged canine hippocampus is reduced by enrichment. Neurobiol Aging 2006; 29:39-50. [PMID: 17092609 PMCID: PMC2198929 DOI: 10.1016/j.neurobiolaging.2006.09.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 09/20/2006] [Accepted: 09/30/2006] [Indexed: 11/12/2022]
Abstract
Neuron loss within the hippocampus and entorhinal cortex occurs as a function of age in humans. We first tested the hypothesis that neuron loss occurs in the aged dog. The total unilateral number of neurons in the canine entorhinal cortex and subdivisions of the hippocampus from the left hemisphere were estimated using the optical fractionator. The brains from 5 old (13.0-15.0 years old) and 5 young (3.4-4.5 years old) beagle dogs were analyzed. The hilus of the hippocampus showed a significant loss of neurons (approximately 30%) in the aged dog brain compared to young. Differences were not detected in the remaining hippocampal subfields and entorhinal cortex. We further tested the hypothesis that an antioxidant fortified food or behavioral enrichment would reduce the age-related loss of hilar neurons. Behaviorally enriched aged dogs had more neurons in the hilus (approximately 18%) compared to aged controls. These results suggest that the aged canine hippocampus in the left hemisphere shows selective neuron loss and that behavioral enrichment may reduce this loss.
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Affiliation(s)
- Christina T Siwak-Tapp
- Institute for Brain Aging and Dementia, University of California, 1226 Gillespie Neuroscience Research Facility, Irvine, CA 92697-4540, USA.
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