title: Maternal care affects the phenotype of a rat model for schizophrenia.
abstract: Schizophrenia is a complex mental disorder caused by an interplay between genetic and environmental factors, including early postnatal stressors. To explore this issue, we use two rat lines, apomorphine-susceptible (APO-SUS) rats that display schizophrenia-relevant features and their phenotypic counterpart, apomorphine-unsusceptible (APO-UNSUS) rats. These rat lines differ not only in their gnawing response to apomorphine, but also in their behavioral response to novelty (APO-SUS: high, APO-UNSUS: low). In this study, we examined the effects of early postnatal cross-fostering on maternal care and on the phenotypes of the cross-fostered APO-SUS and APO-UNSUS animals later in life. Cross-fostered APO-UNSUS animals showed decreased body weights as pups and decreased novelty-induced locomotor activity as adults (i.e., more extreme behavior), in accordance with the less appropriate maternal care provided by APO-SUS vs. their own APO-UNSUS mothers (i.e., the APO-SUS mother displayed less non-arched-back nursing and more self-grooming, and was more away from its nest). In contrast, cross-fostered APO-SUS animals showed increased body weights as pups and reduced apomorphine-induced gnawing later in life (i.e., normalization of their extreme behavior), in line with the more appropriate maternal care provided by APO-UNSUS relative to their own APO-SUS mothers (i.e., the APO-UNSUS mother displayed more non-arched-back nursing and similar self-grooming, and was not more away). Furthermore, we found that, in addition to arched-back nursing, non-arched-back nursing was an important feature of maternal care, and that cross-fostering APO-SUS mothers, but not cross-fostering APO-UNSUS mothers, displayed increased apomorphine-induced gnawing. Thus, cross-fostering not only causes early postnatal stress shaping the phenotypes of the cross-fostered animals later in life, but also affects the phenotypes of the cross-fostering mothers.
authors.affiliation: Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen, Netherlands.
authors.forename: Ruben W M
authors.initials: RW
authors.lastname: van Vugt
authors.affiliation: Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen, Netherlands.
authors.forename: Francisca
authors.initials: F
authors.lastname: Meyer
authors.affiliation: Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen, Netherlands.
authors.forename: Josephus A
authors.initials: JA
authors.lastname: van Hulten
authors.affiliation: Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen, Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Vernooij
authors.affiliation: Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre Nijmegen, Netherlands.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Cools
authors.affiliation: Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre Nijmegen, Netherlands ; Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute La Jolla, CA, USA.
authors.forename: Michel M M
authors.initials: MM
authors.lastname: Verheij
authors.affiliation: Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen, Netherlands.
authors.forename: Gerard J M
authors.initials: GJ
authors.lastname: Martens
keywords: (non-) arched-back nursing; apomorphine-induced gnawing; apomorphine-susceptible/apomorphine-unsusceptible rats; cross-fostering; early-postnatal stress; maternal care; novelty-induced locomotor activity; schizophrenia