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Neurochemical differences in two rat strains exposed to social isolation rearing

Published online by Cambridge University Press:  24 June 2014

Luigia Trabace*
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Margherita Zotti
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Marilena Colaianna
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Maria G. Morgese
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Stefania Schiavone
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Paolo Tucci
Affiliation:
Department of Biomedical Sciences, University of Foggia, Foggia, Italy
Brian H. Harvey
Affiliation:
Unit for Drug Research and Development, Division of Pharmacology, School of Pharmacy, North-West University, Potchefstroom, South Africa
Gregers Wegener
Affiliation:
Centre for Psychiatric Research, University of Aarhus, Aarhus, Denmark
Vincenzo Cuomo
Affiliation:
Department of Human Physiology and Pharmacology, Vittorio Erspamer, University of Rome “La Sapienza”, Rome, Italy
*
Luigia Trabace, PhD, Department of Biomedical Sciences, Faculty of Medicine c/o OO.RR., University of Foggia, Viale L. Pinto, 71100 Foggia, Italy. Tel: +39 0881 588056; Fax: +39 0881 712366; E-mail: [email protected]

Extract

Objective: Isolation rearing of rats provides a non-pharmacological method of inducing behavioural changes in rodents that resemble schizophrenia or depression. Nevertheless, results are variable within different strains. We focused on neurochemical changes in several in vivo and post-mortem brain regions of Wistar (W) and Lister Hooded (LH) rats following post-weaning social separation.

Methods: Experiments were conducted after 6–8 weeks of isolation. For post-mortem studies, prefrontal cortex (PFC), nucleus accumbens (NAC), hippocampus (Hipp) and striatum (St) were collected by tissue dissection. In vivo experiments were conducted by microdialysis in the PFC. Analyses of dopamine (DA), serotonin (5-HT) levels and relative turnover were performed by using high-performance liquid chromatography.

Results: We found significant strain-related differences in biogenic amine content. LH rats were characterised by markedly raised DA, along with its turnover reduction, in all the post-mortem brain regions examined as well as in microdialysis samples, while in W rats 5-HT tissue concentration was lower in PFC and St and higher in NAC and Hipp. Cortical extracellular 5-HT concentrations were increased in group housed and decreased in isolated W animals. Moreover, isolation increased DA concentrations in the PFC of LH rats, and decreased 5-HT in W rats in NAC and Hipp. Lately, 5-HT turnover was also affected by both strain and isolation conditions.

Conclusions: This study suggests that W and LH rats have markedly different neurochemical profiles in response to isolation, resulting in altered monoamine levels that vary according to brain area and rat strain. These findings highlight the importance of selecting an appropriate rat strain when considering isolation rearing to model symptoms of schizophrenia and/or depression.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2012

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