title: Altered taste preference and loss of limbic-projecting serotonergic neurons in the dorsal raphe nucleus of chronically epileptic rats.
abstract: Mood disorders and major depression are frequently comorbid with epilepsy. While the nature of this comorbidity is not fully understood, multiple lines of evidence suggest that changes in serotonin (5-HT) neurotransmission may be an underlying mechanism. In this study, we tested the hypothesis that chronic epilepsy in rats can be associated with loss of 5-HT neurons in the dorsal raphe (DR) nuclear complex, the main source of 5-HT projections to the cerebral cortex, which would help to explain respective behavioral deficits. Epilepsy was induced using the kainate model of status epilepticus in adult Wistar rats. After a 3-month recovery period, all kainate-treated rats that had experienced status epilepticus showed spontaneous seizures and reduced sucrose preference (anhedonia), a core symptom of depression. No changes in the forced swim test were detected. The total numbers of 5-HT immunoreactive cells were estimated in all DR subdivisions of control and epileptic rats. Interestingly, epilepsy-related loss of 5-HT neurons (approximately 35%) was observed only in the interfascicular part of the DR complex, which is known to innervate brain regions involved in depression. These findings support the notion that mental health impairments observed in epilepsy may be related to loss of a specific population of the DR 5-HT neurons projecting to limbic brain areas.
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal; Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal; Medibrain-Centro de Estudos Neurofisiológicos, Vila do Conde, Portugal.
authors.forename: Gisela H
authors.initials: GH
authors.lastname: Maia
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal; Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal.
authors.forename: Joana I
authors.initials: JI
authors.lastname: Soares
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal; Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Andrade
authors.affiliation: Medibrain-Centro de Estudos Neurofisiológicos, Vila do Conde, Portugal.
authors.forename: Juliana F
authors.initials: JF
authors.lastname: Leite
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.
authors.forename: Liliana L
authors.initials: LL
authors.lastname: Luz
authors.affiliation: Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.
authors.forename: José P
authors.initials: JP
authors.lastname: Andrade
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal; Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal; Medibrain-Centro de Estudos Neurofisiológicos, Vila do Conde, Portugal. Electronic address: luk@med.up.pt.
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Lukoyanov
mesh_terms: D059445:Anhedonia / Q000502:physiology; D000818:Animals; D002452:Cell Count; D002908:Chronic Disease; D003866:Depressive Disorder / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D065847:Dorsal Raphe Nucleus / Q000473:pathology* / Q000503:physiopathology; D000069280:Electrocorticography; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology*; D007150:Immunohistochemistry; D007608:Kainic Acid; D008297:Male; D011897:Random Allocation; D017208:Rats, Wistar; D012640:Seizures / Q000473:pathology / Q000503:physiopathology; D059326:Serotonergic Neurons / Q000473:pathology* / Q000502:physiology; D013226:Status Epilepticus / Q000473:pathology / Q000503:physiopathology; D055697:Taste Perception / Q000502:physiology*
chemical_list: D007608:Kainic Acid
keywords: 5-Hydroxytriptophan; Depression; Epilepsy; Interfascicular nucleus; Kainic acid; Stereology