1
|
Sitnikova E. Behavioral and Cognitive Comorbidities in Genetic Rat Models of Absence Epilepsy (Focusing on GAERS and WAG/Rij Rats). Biomedicines 2024; 12:122. [PMID: 38255227 PMCID: PMC10812980 DOI: 10.3390/biomedicines12010122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/02/2024] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
Absence epilepsy is a non-convulsive type of epilepsy characterized by the sudden loss of awareness. It is associated with thalamo-cortical impairment, which may cause neuropsychiatric and neurocognitive problems. Rats with spontaneous absence-like seizures are widely used as in vivo genetic models for absence epilepsy; they display behavioral and cognitive problems similar to epilepsy in humans, such as genetic absence epilepsy rats from Strasbourg (GAERS) and Wistar Albino rats from Rijswijk (WAG/Rij). Depression- and anxiety-like behaviors were apparent in GAERS, but no anxiety and depression-like symptoms were found in WAG/Rij rats. Deficits in executive functions and memory impairment in WAG/Rij rats, i.e., cognitive comorbidities, were linked to the severity of epilepsy. Wistar rats can develop spontaneous seizures in adulthood, so caution is advised when using them as a control epileptic strain. This review discusses challenges in the field, such as putative high emotionality in genetically prone rats, sex differences in the expression of cognitive comorbidities, and predictors of cognitive problems or biomarkers of cognitive comorbidities in absence epilepsy, as well as the concept of "the cognitive thalamus". The current knowledge of behavioral and cognitive comorbidities in drug-naive rats with spontaneous absence epilepsy is beneficial for understanding the pathophysiology of absence epilepsy, and for finding new treatment strategies.
Collapse
Affiliation(s)
- Evgenia Sitnikova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, 5A Butlerova St., Moscow 117485, Russia
| |
Collapse
|
2
|
Rauch E, Ari C, Kovács Z. Dose-Dependent Beneficial Effect of Ketone Supplement-Evoked Ketosis on Anxiety Level in Female WAG/Rij Rats: Sometimes Less Is More. Nutrients 2023; 15:4412. [PMID: 37892486 PMCID: PMC10610400 DOI: 10.3390/nu15204412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
While one-third of the population can be affected by anxiety disorders during their lifetime, our knowledge of the pathophysiology of these disorders is far from complete. Previously, it has been demonstrated in male animals that exogenous ketone supplement-evoked ketosis can decrease anxiety levels in preclinical rodent models, such as Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Thus, in this study, we investigated whether intragastric gavage of the exogenous ketone supplement KEMCT (mix of 1,3-butanediol-acetoacetate diester/ketone ester/KE and medium-chain triglyceride/MCT oil in 1:1 ratio) for 7 days can alter the anxiety levels of female WAG/Rij rats using the light-dark box (LDB) test. We demonstrated that a lower dose of KEMCT (3 g/kg/day) increased blood R-βHB (R-β-hydroxybutyrate) levels and significantly decreased anxiety levels (e.g., increased the time spent in the light compartment) in female WAG/Rij rats on the seventh day of administration. Although the higher KEMCT dose (5 g/kg/day) increased blood R-βHB levels more effectively, compared with the lower KEMCT dose, anxiety levels did not improve significantly. We conclude that ketone supplementation might be an effective strategy to induce anxiolytic effects not only in male but also in female WAG/Rij rats. However, these results suggest that the optimal level may be moderately, not highly, elevated blood R-βHB levels when the goal is to alleviate symptoms of anxiety. More studies are needed to understand the exact mechanism of action of ketone supplementation on anxiety levels and to investigate their use in other animal models and humans for the treatment of anxiety disorders and other mental health conditions.
Collapse
Affiliation(s)
- Enikő Rauch
- Department of Biology, Savaria University Centre, Eötvös Loránd University (ELTE), Károlyi Gáspár tér 4, 9700 Szombathely, Hungary; (E.R.); (Z.K.)
- Institute of Biology, University of Pécs, Ifjúság Str. 6, 7624 Pécs, Hungary
| | - Csilla Ari
- Behavioral Neuroscience Research Laboratory, Department of Psychology, University of South Florida, Tampa, FL 33620, USA
- Ketone Technologies LLC, Tampa, FL 33612, USA
| | - Zsolt Kovács
- Department of Biology, Savaria University Centre, Eötvös Loránd University (ELTE), Károlyi Gáspár tér 4, 9700 Szombathely, Hungary; (E.R.); (Z.K.)
| |
Collapse
|
3
|
Dyomina AV, Smolensky IV, Zaitsev AV. Refinement of the Barnes and Morris water maze protocols improves characterization of spatial cognitive deficits in the lithium-pilocarpine rat model of epilepsy. Epilepsy Behav 2023; 147:109391. [PMID: 37619464 DOI: 10.1016/j.yebeh.2023.109391] [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: 06/22/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/26/2023]
Abstract
Temporal lobe epilepsy (TLE) often causes cognitive impairment, especially a decline in spatial memory. Reductions in spatial memory and learning are also common in rodent models of TLE. The Morris water maze and the Barnes maze are the standard methods for evaluating spatial learning and memory in rodents. However, animals with TLE may exhibit agitation, distress, and fail to follow the paradigmatic context of these tests, making the interpretation of experimental data difficult. This study optimized the procedure of the Morris water maze and the Barnes maze to evaluate spatial learning and memory in rats with the lithium-pilocarpine TLE model (LPM rats). It was demonstrated that LPM rats required a mandatory and prolonged habituation stage for both tests. Therefore, the experimental rats performed relatively well on these tests. Nevertheless, LPM rats exhibited a slower learning process compared to the control rats. LPM rats also showed a reduction in spatial memory formation. This was more pronounced in the Barnes maze. Also, LPM rats utilized a sequential strategy for searching in the Barnes maze and were incapable of developing a more efficient spatial search strategy that is common in control animals. The Barnes maze may be a better choice for assessing search strategies, learning deficits, and spatial memory in rats with TLE when choosing between the two tests. This is because of the risk of unexpected seizure occurrence during the Morris water maze tests, and the potential risks for animal welfare.
Collapse
Affiliation(s)
- Alexandra V Dyomina
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia
| | - Ilya V Smolensky
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia; Department of Community Health, University of Fribourg, Chemin du Musée 4, 1700 Fribourg, Switzerland; Department of Biomedicine, University of Basel, Hebelstrasse 20, 4056 Basel, Switzerland
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS (IEPhB), 44, Toreza pr., Saint Petersburg 194223, Russia.
| |
Collapse
|
4
|
Midzyanovskaya IS, Birioukova LM, Storvik M, Luijtelaar GV, Tuomisto LM. The prefrontal cortex shows widespread decrease in H3 histamine receptor binding densities in rats with genetic generalized epilepsies. Epilepsy Res 2022; 182:106921. [DOI: 10.1016/j.eplepsyres.2022.106921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/19/2022] [Accepted: 04/01/2022] [Indexed: 11/03/2022]
|
5
|
Midzyanovskaya IS, Petrenko TE, Birioukova LM, Tuomisto LM. Reduced H3 histamine receptor binding densities in the upper layers of motor cortex in rats prone to audiogenic convulsive seizures. Epilepsy Res 2020; 170:106543. [PMID: 33387800 DOI: 10.1016/j.eplepsyres.2020.106543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/03/2020] [Accepted: 12/21/2020] [Indexed: 01/11/2023]
Abstract
Fits of audiogenic seizures in rodents are considered as a model for generalized convulsive epilepsies in humans. The laminar distribution of the H3 histamine receptor binding densities was quantified in the motor cortex of two strains of rats with genetically determined generalized epilepsies, namely KM rats with audiogenic seizures only, and WAGRij rats with both audiogenic seizures and absence seizures. It was found that H3 histamine receptor binding densities in layer 2/3d of the primary and secondary motor cortices of the rats that experienced audiogenic seizure fits were significantly lower than in the cortices of control rats. Possible explanations are discussed.
Collapse
Affiliation(s)
- I S Midzyanovskaya
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Russian Federation; University of Eastern Finland, School of Pharmacy, Finland.
| | - T E Petrenko
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Russian Federation; Pirogov Russian National Research Medical University, Russian Federation
| | - L M Birioukova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Russian Federation; University of Eastern Finland, School of Pharmacy, Finland
| | - L M Tuomisto
- University of Eastern Finland, School of Pharmacy, Finland
| |
Collapse
|
6
|
Midzyanovskaya IS, Shatskova AB, MacDonald E, Luijtelaar GV, Tuomisto L. Brain Aminergic Deficiency in Absence Epileptic Rats: Dependency on Seizure Severity and Their Functional Coupling at Rest. ACTA ACUST UNITED AC 2020. [DOI: 10.4236/jbbs.2020.101003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
7
|
Leo A, Citraro R, Tallarico M, Iannone M, Fedosova E, Nesci V, De Sarro G, Sarkisova K, Russo E. Cognitive impairment in the WAG/Rij rat absence model is secondary to absence seizures and depressive-like behavior. Prog Neuropsychopharmacol Biol Psychiatry 2019; 94:109652. [PMID: 31095993 DOI: 10.1016/j.pnpbp.2019.109652] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/30/2019] [Accepted: 05/12/2019] [Indexed: 01/06/2023]
Abstract
Neuropsychiatric comorbidities are common in patients with epilepsy, remaining still an urgent unmet clinical need. Therefore, the management of epileptic disorders should not only be restricted to the achievement of seizure-freedom but must also be able to counteract its related comorbidities. Experimental animal models of epilepsy represent a valid tool not only to study epilepsy but also its associated comorbidities. The WAG/Rij rat is a well-established genetically-based model of absence epilepsy with depressive-like comorbidity, in which learning and memory impairment was also recently reported. Aim of this study was to clarify whether this cognitive decline is secondary or not to absence seizures and/or depressive-like behavior. The behavioral performance of untreated and ethosuximide-treated (300 mg/kg/day; 17 days) WAG/Rij rats at 6 and 12 months of age were assessed in several tests: forced swimming test, objects recognition test, social recognition test, Morris water maze and passive avoidance. According to our results, it seems that cognitive impairment in this strain, similarly to depressive-like behavior, is secondary to the occurrence of absence seizures, which might be necessary for the expression of cognitive impairment. Furthermore, our results suggest an age-dependent impairment of cognitive performance in WAG/Rij rats, which could be linked to the age-dependent increase of spike wave discharges. Consistently, it is possible that absence seizures, depressive-like behavior and cognitive deficit may arise independently and separately in lifetime from the same underlying network disease, as previously suggested for the behavioral features associated with other epileptic syndromes.
Collapse
Affiliation(s)
- Antonio Leo
- University of Catanzaro, School of Medicine, Science of Health Dept., Catanzaro, Italy
| | - Rita Citraro
- University of Catanzaro, School of Medicine, Science of Health Dept., Catanzaro, Italy.
| | - Martina Tallarico
- University of Catanzaro, School of Medicine, Science of Health Dept., Catanzaro, Italy; CNR, Institute of Neurological Sciences, Pharmacology Section, Roccelletta di Borgia, Catanzaro, Italy
| | - Michelangelo Iannone
- CNR, Institute of Neurological Sciences, Pharmacology Section, Roccelletta di Borgia, Catanzaro, Italy
| | - Ekaterina Fedosova
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, Russia
| | - Valentina Nesci
- University of Catanzaro, School of Medicine, Science of Health Dept., Catanzaro, Italy
| | | | - Karine Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, Russia
| | - Emilio Russo
- University of Catanzaro, School of Medicine, Science of Health Dept., Catanzaro, Italy
| |
Collapse
|
8
|
Leo A, Citraro R, Amodio N, De Sarro C, Gallo Cantafio ME, Constanti A, De Sarro G, Russo E. Fingolimod Exerts only Temporary Antiepileptogenic Effects but Longer-Lasting Positive Effects on Behavior in the WAG/Rij Rat Absence Epilepsy Model. Neurotherapeutics 2017; 14:1134-1147. [PMID: 28653281 PMCID: PMC5722759 DOI: 10.1007/s13311-017-0550-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
One of the major challenges in the epilepsy field is identifying disease-modifying drugs in order to prevent or delay spontaneous recurrent seizure onset or to cure already established epilepsy. It has been recently reported that fingolimod, currently approved for the treatment of relapsing-remitting multiple sclerosis, has demonstrated antiepileptogenic effects in 2 different preclinical models of acquired epilepsy. However, to date, no data exist regarding the role of fingolimod against genetic epilepsy. Therefore, we have addressed this issue by studying the effects of fingolimod in Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats, a well-established genetic model of absence epilepsy, epileptogenesis, and neuropsychiatric comorbidity. Our results have demonstrated that an early long-term treatment with fingolimod (1 mg/kg/day), started before absence seizure onset, has both antiepileptogenic and antidepressant-like effects in WAG/Rij rats. However, these effects were transitory, as 5 months after treatment discontinuation, both absence seizure and depressive like-behavior returned to control levels. Furthermore, a temporary reduction of mTOR signaling pathway activity, indicated by reduced phosphorylated mammalian target of rapamycin and phosphorylated p70S6k levels, and by increased phosphorylated Akt in WAG/Rij rats of 6 months of age accompanied the transitory antiepileptogenic effects of fingolimod. Surprisingly, fingolimod has demonstrated longer-lasting positive effects on cognitive decline in this strain. This effect was accompanied by an increased acetylation of lysine 8 of histone H4 (at both 6 and 10 months of age). In conclusion, our results support the antiepileptogenic effects of fingolimod. However, the antiepileptogenic effects were transitory. Moreover, fingolimod might also have a positive impact on animal behavior and particularly in protecting the development of memory decline.
Collapse
Affiliation(s)
- Antonio Leo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | - Nicola Amodio
- Department of Experimental and Clinical Medicine, Magna Graecia University and Translational Medical Oncology Unit, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Caterina De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | - Maria Eugenia Gallo Cantafio
- Department of Experimental and Clinical Medicine, Magna Graecia University and Translational Medical Oncology Unit, Salvatore Venuta University Campus, Catanzaro, Italy
| | | | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| |
Collapse
|
9
|
Genetic background contributes to the co-morbidity of anxiety and depression with audiogenic seizure propensity and responses to fluoxetine treatment. Epilepsy Behav 2017; 68:95-102. [PMID: 28135595 DOI: 10.1016/j.yebeh.2016.12.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/24/2016] [Accepted: 12/17/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND Anxiety and depression are the most frequent comorbidities of different types of convulsive and non-convulsive epilepsies. Increased anxiety and depression-like phenotype have been described in the genetic absence epilepsy models as well as in models of limbic epilepsy and acquired seizure models, suggesting a neurobiological connection. However, whether anxiety and/or depression are comorbid to audiogenic epilepsy remains unclear. The aim of this study was to investigate whether anxiety or depression-like behavior can be found in rat strains with different susceptibility to audiogenic seizures (AS) and whether chronic fluoxetine treatment affects this co-morbidity. METHODS Behavior in the elevated plus-maze and the forced swimming test was studied in four strains: Wistar rats non-susceptible to AS; Krushinsky-Molodkina (KM) strain, selectively bred for AS propensity from outbred Wistar rats; and a selection lines bred for maximal AS expression (strain "4") and for a lack of AS (strain "0") from KM×Wistar F2 hybrids. Effects of chronic antidepressant treatment on AS and behavior were also evaluated. RESULTS Anxiety and depression levels were higher in KM rats (with AS) compared with Wistar rats (without AS), indicating the comorbidity with AS. However, in strains "4" and "0" with contrasting AS expression, but with a genetic background close to KM rats, anxiety and depression were not as divergent as in KMs versus Wistars. Fluoxetine treatment exerted an antidepressant effect in all rat strains irrespective of its effect on AS. CONCLUSIONS Genetic background contributes substantively to the co-morbidity of anxiety and depression with AS propensity.
Collapse
|
10
|
Midzyanovskaya IS, Birioukova LM, Shatskova AB, van Luijtelaar G, Tuomisto LM. H1 histamine receptor densities are increased in brain regions of rats with genetically generalized epilepsies. Epilepsy Res 2016; 127:135-140. [DOI: 10.1016/j.eplepsyres.2016.08.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/11/2016] [Accepted: 08/23/2016] [Indexed: 10/21/2022]
|
11
|
Sarkissova KY, Fedotova IB, Surina NM, Nikolaev GM, Perepelkina OV, Poletaeva II. Effect of chronic fluoxetine treatment on audiogenic epilepsy, symptoms of anxiety and depression in rats of four lines. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2016; 467:55-8. [PMID: 27193875 DOI: 10.1134/s0012496616020058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Indexed: 11/22/2022]
Abstract
Anxiety (Anx) and depression (Dp) levels were evaluated in rats of 4 lines: 2 of them (KM and "4") exhibited audiogenic seizures (AS), and 2 (Wistar and "0") had no AS. In KM rats (with AS), Anx and Dp levels were higher than in Wistars (without AS), while in "4" and "0" rats with the related genetic background but contrasting in AS severity, Anx and Dp indices were not different. Fluoxetine treatment exerted antidepressant effect in all rat lines irrespective of its effect on AS. Thus, phenotypic expression of AS is not directly associated with the mechanisms of Anx and Dp development.
Collapse
Affiliation(s)
- K Yu Sarkissova
- Institute of Higher Nervous Activity and Neurophysiology, RAS, Moscow, Russia
| | | | | | | | | | | |
Collapse
|
12
|
Srimontri P, Endo S, Sakamoto T, Nakayama Y, Kurosaka A, Itohara S, Hirabayashi Y, Kato K. Sialyltransferase ST3Gal IV deletion protects against temporal lobe epilepsy. J Neurochem 2014; 131:675-87. [PMID: 25066807 DOI: 10.1111/jnc.12838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/23/2014] [Accepted: 07/23/2014] [Indexed: 11/27/2022]
Abstract
Temporal lobe epilepsy (TLE) often becomes refractory, and patients with TLE show a high incidence of psychiatric symptoms, including anxiety and depression. Therefore, it is necessary to identify molecules that were previously unknown to contribute to epilepsy and its associated disorders. We previously found that the sialyltransferase ST3Gal IV is up-regulated within the neural circuits through which amygdala-kindling stimulation propagates epileptic seizures. In contrast, this study demonstrated that kindling stimulation failed to evoke epileptic seizures in ST3Gal IV-deficient mice. Furthermore, approximately 80% of these mice failed to show tonic-clonic seizures with stimulation, whereas all littermate wild-type mice showed tonic-clonic seizures. This indicates that the loss of ST3Gal IV does not cause TLE in mice. Meanwhile, ST3Gal IV-deficient mice exhibited decreased acclimation in the open field test, increased immobility in the forced swim test, enhanced freezing during delay auditory fear conditioning, and sleep disturbances. Thus, the loss of ST3Gal IV modulates anxiety-related behaviors. These findings indicate that ST3Gal IV is a key molecule in the mechanisms underlying anxiety - a side effect of TLE - and may therefore also be an effective target for treating epilepsy, acting through the same circuits.
Collapse
Affiliation(s)
- Paitoon Srimontri
- Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto, Japan
| | | | | | | | | | | | | | | |
Collapse
|
13
|
NK1 receptors antagonism of dorsal hippocampus counteract the anxiogenic-like effects induced by pilocarpine in non-convulsive Wistar rats. Behav Brain Res 2014; 265:53-60. [DOI: 10.1016/j.bbr.2014.01.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 01/28/2014] [Accepted: 01/31/2014] [Indexed: 11/21/2022]
|
14
|
Sawyer NT, Papale LA, Eliason J, Neigh GN, Escayg A. Scn8a voltage-gated sodium channel mutation alters seizure and anxiety responses to acute stress. Psychoneuroendocrinology 2014; 39:225-236. [PMID: 24138934 PMCID: PMC3989103 DOI: 10.1016/j.psyneuen.2013.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 12/30/2022]
Abstract
Stress is known to trigger seizures in patients with epilepsy, highlighting the physiological stress response as a possible therapeutic target for epilepsy treatment. Nevertheless, little is currently known about how a genetic predisposition to epilepsy interacts with the stress response to influence seizure outcome. To address this question, we examined the effect of acute stress on seizure outcome in mice with mutations in the voltage-gated sodium channel (VGSC) gene Scn8a. Scn8a mutants display spontaneous spike-wave discharges (SWDs) characteristic of absence epilepsy. We saw that the baseline frequency of SWDs in Scn8a mutants correlates closely with the diurnal activity of the hypothalamic-pituitary-adrenal (HPA) axis, with a peak in seizure activity occurring at around the same time as the peak in corticosterone (1700-1900h). A 20-min acute restraint stress administered in the morning increases the frequency of spontaneous SWDs immediately following the stressor. Seizure frequency then returns to baseline levels within 3h after stressor exposure, but the subsequent evening peak in seizure frequency is delayed and broadened, changes that persist into the next evening and are accompanied by long-lasting changes in HPA axis activity. Scn8a mutants also show increased anxiety-like behavior in mildly stressful situations. A 20-min acute restraint stress can also increase the severity and duration of chemically induced seizures in Scn8a mutants, changes that differ from wild-type littermates. Overall, our data show that a voltage-gated sodium channel mutation can alter the behavioral response to stress and can interact with the stress response to alter seizure outcome.
Collapse
Affiliation(s)
- Nikki T Sawyer
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Ligia A Papale
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Jessica Eliason
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Gretchen N Neigh
- Department of Physiology and Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, USA.
| |
Collapse
|
15
|
Karson A, Utkan T, Balcı F, Arıcıoğlu F, Ateş N. Age-dependent decline in learning and memory performances of WAG/Rij rat model of absence epilepsy. Behav Brain Funct 2012; 8:51. [PMID: 22998946 PMCID: PMC3514399 DOI: 10.1186/1744-9081-8-51] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Accepted: 09/19/2012] [Indexed: 12/11/2022] Open
Abstract
Recent clinical studies revealed emotional and cognitive impairments associated with absence epilepsy. Preclinical research with genetic models of absence epilepsy however have primarily focused on dysfunctional emotional processes and paid relatively less attention to cognitive impairment. In order to bridge this gap, we investigated age-dependent changes in learning and memory performance, anxiety-like behavior, and locomotor activity of WAG/Rij rats (a valid model of generalized absence epilepsy) using passive avoidance, Morris water maze, elevated plus maze, and locomotor activity cage. We tested 5 month-old and 13 month-old WAG/Rij rats and compared their performance to age-matched Wistar rats. Results revealed a decline in emotional and spatial memory of WAG/Rij rats compared to age-matched Wistar rats only at 13 months of age. Importantly, there were no significant differences between WAG/Rij and Wistar rats in terms of anxiety-like behavior and locomotor activity at either age. Results pointed at age-dependent learning and memory deficits in the WAG/Rij rat model of absence epilepsy.
Collapse
Affiliation(s)
- Ayşe Karson
- Medical School, Department of Physiology, Kocaeli University, Umuttepe, Kocaeli, 41380, Turkey.
| | | | | | | | | |
Collapse
|
16
|
Samotaeva IS, Birioukova LM, Midzyanovskaya IS, Kuznetsova GD, Bazyan AS, Tuomisto L. Metoprine induced behavioral modifications and brain regional histamine increase in WAG/Rij and Wistar rats. Epilepsy Res 2012; 101:148-56. [DOI: 10.1016/j.eplepsyres.2012.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 03/05/2012] [Accepted: 03/19/2012] [Indexed: 11/26/2022]
|
17
|
The prevention of behavioral consequences of idiopathic generalized epilepsy: Evidence from rodent models. Neurosci Lett 2011; 497:177-84. [DOI: 10.1016/j.neulet.2011.02.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 02/15/2011] [Indexed: 12/29/2022]
|
18
|
Sarkisova K, van Luijtelaar G. The WAG/Rij strain: a genetic animal model of absence epilepsy with comorbidity of depression [corrected]. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:854-76. [PMID: 21093520 DOI: 10.1016/j.pnpbp.2010.11.010] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 09/28/2010] [Accepted: 11/09/2010] [Indexed: 01/02/2023]
Abstract
A great number of clinical observations show a relationship between epilepsy and depression. Idiopathic generalized epilepsy, including absence epilepsy, has a genetic basis. The review provides evidence that WAG/Rij rats can be regarded as a valid genetic animal model of absence epilepsy with comorbidity of depression. WAG/Rij rats, originally developed as an animal model of human absence epilepsy, share many EEG and behavioral characteristics resembling absence epilepsy in humans, including the similarity of action of various antiepileptic drugs. Behavioral studies indicate that WAG/Rij rats exhibit depression-like symptoms: decreased investigative activity in the open field test, increased immobility in the forced swimming test, and decreased sucrose consumption and preference (anhedonia). In addition, WAG/Rij rats adopt passive strategies in stressful situations, express some cognitive disturbances (reduced long-term memory), helplessness, and submissiveness, inability to make choice and overcome obstacles, which are typical for depressed patients. Elevated anxiety is not a characteristic (specific) feature of WAG/Rij rats; it is a characteristic for only a sub-strain of WAG/Rij rats susceptible to audiogenic seizures. Interestingly, WAG/Rij rats display a hyper-response to amphetamine similar to anhedonic depressed patients. WAG/Rij rats are sensitive only to chronic, but not acute, antidepressant treatments, suggesting that WAG/Rij rats fulfill a criterion of predictive validity for a putative animal model of depression. However, more and different antidepressant drugs still await evaluation. Depression-like behavioral symptoms in WAG/Rij rats are evident at baseline conditions, not exclusively after stress. Experiments with foot-shock stress do not point towards higher stress sensitivity at both behavioral and hormonal levels. However, freezing behavior (coping deficits) and blunted response of 5HT in the frontal cortex to uncontrollable sound stress, increased c-fos expression in the terminal regions of the meso-cortico-limbic brain systems and greater DA response of the mesolimbic system to forced swim stress suggest that WAG/Rij rats are vulnerable to some, but not to all types of stressors. We propose that genetic absence epileptic WAG/Rij rats have behavioral depression-like symptoms, are vulnerable to stress and might represent a model of chronic low-grade depression (dysthymia). Both 5HT and DAergic abnormalities detected in the brain of WAG/Rij rats are involved in modulation of vulnerability to stress and provocation of behavioral depression-like symptoms. The same neurotransmitter systems modulate SWDs as well. Recent studies suggest that the occurrence and repetition of absence seizures are a precipitant of depression-like behavior. Whether the neurochemical changes are primary to depression-like behavioral alterations remains to be determined. In conclusion, the WAG/Rij rats can be considered as a genetic animal model for absence epilepsy with comorbidity of dysthymia. This model can be used to investigate etiology, pathogenic mechanisms and treatment of a psychiatric comorbidity, such as depression in absence epilepsy, to reveal putative genes contributing to comorbid depressive disorder, and to screen novel psychotropic drugs with a selective and/or complex (dual) action on both pathologies.
Collapse
Affiliation(s)
- Karine Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerov str. 5a, Moscow 117485, Russia.
| | | |
Collapse
|
19
|
Wu YC, Wang YJ, Tseng GF. Ascorbic acid and α-tocopherol supplement starting prenatally enhances the resistance of nucleus tractus solitarius neurons to hypobaric hypoxic challenge. Brain Struct Funct 2011; 216:105-22. [PMID: 21287201 DOI: 10.1007/s00429-010-0300-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 12/30/2010] [Indexed: 12/15/2022]
Abstract
Hypobaric hypoxia, encountered at high altitude, could result in severe consequences. Ascorbic acid (AA) and α-tocopherol (αTC), the two readily available over-the-counter antioxidants, are known to protect nervous tissue against oxidative stress. Here we study whether AA or αTC supplement starting prenatally protects animals against hypobaric hypoxic challenge at adulthood. Expressions of c-fos and the NR1 subunit of the N-methyl-D-aspartate receptors in the nucleus tractus solitarius (NTS) subserving cardiorespiratory functions were investigated. AA and αTC supplement reduced the number of c-fos immunoreactive neurons and intensity of NR1 expression in young and adult animals under normoxia. The treatment, in addition, attenuated the activation of NTS neurons, in terms of c-fos and NR1 expressions, and reduced the anxiety behaviors of adult rats subjected to hypobaric hypoxic challenge. Reduction of c-fos immunoreactive neurons was found concentrated in the chemoreceptor, baroreceptor, and tracheobronchial tree NTS subnuclei that receive corresponding afferents. The protective effect was not found in normal adult animals supplemented with AA or αTC a week before hypobaric hypoxic challenge. In short, prenatal and sustained AA or αTC supplement altered NTS substrate and ameliorated animals' reactions to hypobaric hypoxic insult, suggesting that this may be considered to protect animals from hypoxic insults from young to adult.
Collapse
Affiliation(s)
- Ya-Chieh Wu
- Institute of Anatomy and Cell Biology, College of Medicine, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei, Taiwan
| | | | | |
Collapse
|
20
|
Duarte FS, Gavioli EC, Duzzioni M, Hoeller AA, Canteras NS, De Lima TCM. Short- and long-term anxiogenic effects induced by a single injection of subconvulsant doses of pilocarpine in rats: investigation of the putative role of hippocampal pathways. Psychopharmacology (Berl) 2010; 212:653-61. [PMID: 20803001 DOI: 10.1007/s00213-010-1985-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 08/04/2010] [Indexed: 01/13/2023]
Abstract
RATIONALE Behavioral consequences of convulsive episodes are well documented, but less attention was paid to changes that occur in response to subconvulsant doses of drugs. OBJECTIVES We investigated short- and long-term effects of a single systemic injection of a subconvulsant dose of pilocarpine on the behavior of rats as evaluated in the elevated plus maze. METHODS AND RESULTS Pilocarpine induced an anxiogenic-like profile 24 h later, and this effect persisted for up to 3 months (% of time spent on open arms at 24 h, control = 35.47 ± 3.23; pilocarpine 150 = 8.2 ± 2.6; 3 months, control = 31.9 ± 5.5; pilocarpine 150 = 9.3 ± 4.9). Temporary inactivation of fimbria-fornix with lidocaine 4% promoted an anxiolytic-like effect per se, suggesting a tonic control of this pathway on the modulation of anxiety-related behaviors. Lidocaine also reduced the anxiogenic-like profile of animals tested 1 month after pilocarpine treatment (% of time spent on open arms, saline + phosphate-buffered saline (PBS) = 31.7 + 3.7; saline + lidocaine = 54.4 + 4.7; pilocarpine + PBS = 10.3 + 4.1; pilocarpine + lidocaine = 40.1 + 9.1). To determine whether the anxiogenic-like effect was mediated by septal region or by direct hippocampal projections to the diencephalon, the neural transmission of post-commissural fornix was blocked, and a similar reduction in the anxiogenic-like effect of pilocarpine was observed. CONCLUSIONS Our findings suggest that a single systemic injection of pilocarpine may induce long-lasting anxiogenic-like behavior in rats, an effect that appears to be mediated, in part, through a direct path from hippocampus to medial hypothalamic sites involved in fear responses.
Collapse
Affiliation(s)
- Filipe Silveira Duarte
- Department of Pharmacology, CCB, Federal University of Santa Catarina, Campus Universitário, Trindade, Florianópolis, SC, Brazil
| | | | | | | | | | | |
Collapse
|
21
|
Heinrichs SC. Neurobehavioral consequences of stressor exposure in rodent models of epilepsy. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:808-15. [PMID: 19913590 DOI: 10.1016/j.pnpbp.2009.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 10/22/2009] [Accepted: 11/03/2009] [Indexed: 12/20/2022]
Abstract
Both normal, non-epileptic as well as seizure-prone rodents exhibit a spectrum of anxiogenic-like behaviors in response to stressor exposure. Comparative analysis reveals that the same set of emotionality dependent measures is sensitive to both stress reactivity in normal rodents as well as stress hyperreactivity typically seen in seizure-prone rodents. A variety of unconditioned, exploratory tasks reflect global sensitivity to stressor exposure in the form of behavioral inhibition of locomotor output. Moreover, well chosen stressors can trigger de novo seizures with or without a history of seizure incidence. Seizures may be elicited in response to stressful environmental stimuli such as noxious noises, tail suspension handling, or home cage disturbance. Stress reactivity studies in rodents with a genetic predisposition to seizures have yielded important clues regarding brain substrates that mediate seizure ontogeny and modulate ictogenesis. Brains of seizure susceptible rodents reflect elevated content of the stress-related neuropeptide, corticotropin-releasing factor (CRF) in several nuclei relative to non-susceptible controls and neutralization of brain CRF attenuates seizure sensitivity. Findings outlined in this review support a diathesis-stress hypothesis in which behavioral- and neuro-pathologies of genetically seizure susceptible rodents arise in part due to multifaceted hyperreactivity to noxious environmental stimuli.
Collapse
Affiliation(s)
- Stephen C Heinrichs
- Regis College, Psychology Department, Science Building 103, 235 Wellesley Street, Weston, MA 02493, United States.
| |
Collapse
|
22
|
Sarkisova KY, Kuznetsova GD, Kulikov MA, van Luijtelaar G. Spike-wave discharges are necessary for the expression of behavioral depression-like symptoms. Epilepsia 2009; 51:146-60. [PMID: 19674046 DOI: 10.1111/j.1528-1167.2009.02260.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE The WAG/Rij strain of rats, a well-established model for absence epilepsy, has comorbidity for depression. These rats exhibit depression-like behavioral symptoms such as increased immobility in the forced swimming test and decreased sucrose intake and preference (anhedonia). These depression-like behavioral symptoms are evident in WAG/Rij rats, both at 3-4 and 5-6 months of age, with a tendency to aggravate in parallel with an increase in seizure duration. Here we investigated whether the behavioral symptoms of depression could be prevented by the suppression of absence seizures. METHODS Ethosuximide (ETX; 300 mg/kg/day, in the drinking water) was chronically applied to WAG/Rij rats from postnatal day 21 until 5 months. Behavioral tests were done before the cessation of the treatment. Electroencephalography (EEG) recordings were made before and after cessation of treatment to measure seizure severity at serial time-points. RESULTS ETX-treated WAG/Rij rats exhibited no symptoms of depression-like behavior in contrast to untreated WAG/Rij rats of the same age. Moreover, treated WAG/Rij rats did not differ from control age-matched Wistar rats. ETX treatment led to almost complete suppression of spike-wave discharges (SWDs) in 5-6 month old WAG/Rij rats. Discontinuation of chronic treatment was accompanied by a gradual emergence of SWDs; however, a persistent reduction in seizure activity was still present 47 days after discontinuation of the chronic treatment. DISCUSSION The results suggest that seizure activity is necessary for the expression of depression-like behavioral symptoms and confirm that epileptogenesis can be prevented by early and chronic treatment.
Collapse
Affiliation(s)
- Karine Yu Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerov street 5A, Moscow 117485, Russia.
| | | | | | | |
Collapse
|
23
|
Govic A, Levay EA, Kent S, Paolini AG. The social behavior of male rats administered an adult-onset calorie restriction regimen. Physiol Behav 2009; 96:581-5. [DOI: 10.1016/j.physbeh.2008.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 10/30/2008] [Accepted: 12/17/2008] [Indexed: 11/27/2022]
|
24
|
Heinrichs SC, Bromfield EB. Behavioral measures in animal studies: relevance to patients with epilepsy. Epilepsy Behav 2008; 12:612-21. [PMID: 18166501 DOI: 10.1016/j.yebeh.2007.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 11/23/2007] [Indexed: 11/27/2022]
Abstract
The relevance of behavioral endpoints in animal seizure models to clinical epilepsy is outlined and enhanced in the present review by linking specific preclinical dependent measures with a quality-of-life scale that serves as an index of the health and welfare of patients with epilepsy (Quality of Life in Epilepsy inventory). This preclinical-to-clinical translation is possible based on existing literature within at least three behavioral domains: (1) physical and motor actions, (2) affective and emotional responses to environmental challenge, and (3) social, sexual, and parental functions. Face valid commonalities in observable behaviors are emphasized with the goal of engaging basic and applied researchers in collaborative research projects to accelerate the pace of discovery in the behavioral phenotyping of epilepsy field.
Collapse
Affiliation(s)
- Stephen C Heinrichs
- VA Medical Center, Research 151-Neuropharmacology, 150 South Huntington Avenue, Boston, MA 02130, USA.
| | | |
Collapse
|
25
|
Sarkisova KY, Kulikov MA, Midzyanovskaya IS, Folomkina AA. Dopamine-dependent nature of depression-like behavior in WAG/Rij rats with genetic absence epilepsy. ACTA ACUST UNITED AC 2008; 38:119-28. [PMID: 18197376 DOI: 10.1007/s11055-008-0017-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 11/09/2006] [Indexed: 11/29/2022]
Abstract
WAG/Rij rats given placebo showed a depression-like state as compared with normal Wistar rats (lacking convulsive pathology); this was analogous to the state previously seen in rats of this line, with decreased investigative activity in the open field test, increased immobility in the forced swimming test, and decreased consumption and preference for sucrose solution (anhedonia). Chronic administration of the tricyclic antidepressant imipramine (15 mg/kg, i.p., 15 days) had therapeutic (antidepressant) effects on depression-like behavior in WAG/Rij rats. After withdrawal of antidepressant therapy, the behavior of WAG/Rij rats was not significantly different from that of Wistar rats. Acute (single-dose) administration of the selective dopamine D2/D3 receptor antagonist raclopride (100 microg/kg, i.p., 15 min before the start of behavioral testing) increased the symptoms of depression-like behavior and suppressed the antidepressant effect of chronic administration of imipramine in WAG/Rij rats. Raclopride had no significant effect on behavior in Wistar rats. Administration of the dopamine D2/D3 receptor agonist parlodel (a therapeutic form of bromocriptine) cured the depression-like behavior of WAG/Rij rats and had no significant effect on behavior in Wistar rats, with the exception of a reduction in the duration of immobility in the forced swimming test. Imipramine and raclopride had no significant effect on the levels of total movement activity and anxiety in either WAG/Rij or Wistar rats. These results demonstrate the dopamine-dependent nature of depression-like behavior in WAG/Rij rats and show the possible involvement of dopamine D2 receptors in mediating the antidepressant effect of imipramine on genetically determined depression-like behavior in WAG/Rij rats.
Collapse
Affiliation(s)
- K Yu Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow.
| | | | | | | |
Collapse
|
26
|
Elevated anxiety and depressive-like behavior in a rat model of genetic generalized epilepsy suggesting common causation. Exp Neurol 2008; 209:254-60. [DOI: 10.1016/j.expneurol.2007.09.026] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 09/24/2007] [Accepted: 09/25/2007] [Indexed: 01/04/2023]
|
27
|
Forcelli PA, Orefice LL, Heinrichs SC. Neural, endocrine and electroencephalographic hyperreactivity to human contact: a diathesis-stress model of seizure susceptibility in El mice. Brain Res 2007; 1144:248-56. [PMID: 17320061 DOI: 10.1016/j.brainres.2007.01.100] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 11/11/2006] [Accepted: 01/25/2007] [Indexed: 11/22/2022]
Abstract
The El mouse strain provides a non-induced model of idiopathic, multifactorial epilepsy in which seizures are elicited in response to stressful environmental stimuli such as tail suspension handling. In the present studies, genetically seizure susceptible El and non-susceptible ddY control mice were exposed to tail suspension, foot-shock and social stressors in order to test the hypothesis that neural and physiological responses to such stimuli would be exaggerated in the El strain. The first experiment assessed neural cell density, stress neuropeptide (corticotropin releasing factor--CRF) levels, and plasma corticosterone activation in El and ddY mice in an unhandled control condition or following exposure to tail suspension or foot-shock stressors. The second experiment assessed brain electroencephalographic activity using telemetrically monitored skull surface electrodes in El and ddY mice exposed to tail suspension or social interaction stressors. Assessment of El mouse brains revealed higher cell counts in amygdala and elevated CRF peptide content in the paraventricular thalamic nucleus relative to ddY controls. El mice exhibited significantly elevated plasma corticosterone levels 60 min following exposure to tail suspension and foot-shock stressors relative to ddY controls. Finally, El mice exhibited significantly elevated brain electroencephalographic (1-4 Hz) activity in response to tail suspension, but not social interaction, relative to ddY controls. These results indicate that potentiated neural, endocrine and physiological activation arises in the El strain following exposure to a known seizure trigger stimulus, involuntary tail suspension handling. The findings support a diathesis-stress hypothesis in which genetically seizure susceptible El mice exhibit a multifaceted hyperreactivity to noxious environmental stimuli.
Collapse
Affiliation(s)
- Patrick A Forcelli
- Department of Psychology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA
| | | | | |
Collapse
|
28
|
Midzyanovskaya IS, Kuznetsova GD, van Luijtelaar ELJM, van Rijn CM, Tuomisto L, Macdonald E. The brain 5HTergic response to an acute sound stress in rats with generalized (absence and audiogenic) epilepsy. Brain Res Bull 2006; 69:631-8. [PMID: 16716830 DOI: 10.1016/j.brainresbull.2006.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 03/03/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
The brain serotoninergic (5HTergic) system of epileptic subjects can influence their vulnerability to stress. We studied the putative dependency of 5HT neurotransmission parameters on emotional stress, and the presence, types and severity of seizures using rats with genetic generalized (absence and/or audiogenic) epilepsy, of WAG/Rij and Wistar strains. The animals were stressed by exposure to a short aversive noise or left without sound stimulation. Tissue concentrations of 5HT, tryptophan (TRT) and 5-hydroxyindolacetic acid (5HIAA) were assessed by HPLC. The stressor activated the 5HTergic system within thalamus (5HIAA elevated), frontal cortex (5HT, TRT elevated), hypothalamus (increased TRT) in all rats. However, the normal (non-epileptic) rats displayed the highest response in the frontal cortex and the lowest one in the thalamus, as compared to the epileptic rats. Absence-epileptic rats exhibited higher thalamic 5HIAA increase than their controls. Significant correlations existed between propensity of absence epilepsy and 5HTergic parameters measured in the cortex and hypothalamus of absence-epileptic rats. No major difference was found between groups with and without audiogenic epilepsy. The results imply that the stress response depends on the presence of epileptic pathology and the seizure type and severity. The brain 5HT may be involved in the control of the paroxysms and behaviour in absence-epileptic subjects.
Collapse
Affiliation(s)
- I S Midzyanovskaya
- Department of Pharmacology and Toxicology, University of Kuopio, Finland.
| | | | | | | | | | | |
Collapse
|