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Epps SA, Tabb KD, Lin SJ, Kahn AB, Javors MA, Boss-Williams KA, Weiss JM, Weinshenker D. Seizure susceptibility and epileptogenesis in a rat model of epilepsy and depression co-morbidity. Neuropsychopharmacology 2012; 37:2756-63. [PMID: 22871911 PMCID: PMC3499730 DOI: 10.1038/npp.2012.141] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Although a strong co-morbidity exists clinically between epilepsy and depression, the cause of this co-morbidity remains unknown, and a valid animal model is crucial for the identification of underlying mechanisms and the development of a screening tool for novel therapies. Although some rodent models of epilepsy have been reported to display behaviors relevant to affective disorders, the seizure susceptibility of animals prone to depression-like behavior has not been characterized. Toward this end, we assessed several forms of seizure sensitivity and epileptogenesis in rats selectively bred for vulnerability (Swim Lo-Active; SwLo) or resilience (Swim High-Active; SwHi) to depression-like phenotypes. The SwLo rats exhibit decreased motor activity in a swim test and other depression-like phenotypes, whereas the SwHi rats display increased motor activity in a swim test. SwLo rats exhibited a decreased latency to limbic motor seizures following acute pilocarpine administration in the absence of differences in pilocarpine pharmacokinetics, and also had a decreased threshold to tonic seizures induced by electroshock. Approximately half of the SwLo rats, but none of the SwHi rats, had spontaneous limbic motor seizures 5 weeks following pilocarpine-induced status epilepticus. While the number of stimulations required to achieve full amygdala and hippocampal electrical kindling were similar in the two rat lines, SwLo rats had a lower final hippocampal kindling threshold and more wet dog shakes during both amygdala and hippocampal kindling. Combined, these results indicate that SwLo rats are a model of epilepsy and depression co-morbidity that can be used for investigating underlying neurobiological and genetic mechanisms and screening novel therapeutics.
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Affiliation(s)
- S Alisha Epps
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Kroshona D Tabb
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Sharon J Lin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexa B Kahn
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Martin A Javors
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA
| | | | - Jay M Weiss
- Department of Psychiatry, Emory University School of Medicine, Atlanta, GA, USA
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA,Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael St, Atlanta, GA 30322, USA, Tel: +404 727 3106, Fax: +404 727 3949, E-mail:
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Tabb K, Boss-Williams KA, Weiss JM, Weinshenker D. Rats bred for susceptibility to depression-like phenotypes have higher kainic acid-induced seizure mortality than their depression-resistant counterparts. Epilepsy Res 2007; 74:140-6. [PMID: 17400428 PMCID: PMC1940038 DOI: 10.1016/j.eplepsyres.2007.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Revised: 01/30/2007] [Accepted: 02/26/2007] [Indexed: 11/23/2022]
Abstract
Epidemiological evidence suggests that epilepsy and depression are comorbid diseases. In fact, depression is the most common neuropsychiatric disorder associated with epilepsy, particularly temporal lobe epilepsy, and individuals with a history of depression are at a higher risk for developing epilepsy than the general population. Despite the epidemiological evidence for this link, there has been little experimental evidence to support the connection or elucidate possible underlying mechanisms. In an effort to address this problem and develop an animal model of epilepsy and depression comorbidity, we assessed seizure susceptibility and severity parameters in rats selectively bred for either susceptibility (the SwLo, SUS, and HYPER lines) or resistance (the SwHi, RES, and MON RES lines) to depression-like phenotypes. We found that rats bred for susceptibility to depression-like phenotypes experienced higher mortality following kainic acid-induced seizures than their resistant counterparts. In contrast, most line differences were not recapitulated when flurothyl was used to elicit seizures. Stress reduced kainic acid-induced mortality rates in all lines except the HYPER rats, supporting previously established indications that the stress response of HYPER rats is abnormal. These combined results support a neurobiological link between epilepsy and depression, advancing us towards an animal model of their comorbidity.
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Affiliation(s)
- Kroshona Tabb
- Department of Human Genetics, Emory University School of Medicine, Whitehead 301, 615 Michael Street, Atlanta, GA 30322, USA
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