András Hugó Lékó1,2, Edina Udvari3, Árpád Dobolyi1,3
1 Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University
2 Department of Psychiatry and Psychotherapy, Semmelweis University
3 MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungarian Academy of Sciences and Eötvös Loránd University
Introduction: Postpartum physiological and behavioural changes are important parts of reproduction and require an adaptation of the central nervous system. This adaptation is regulated by a complex neuronal network, which includes parts of the hypothalamus. Rodent mothers have been considered an excellent model system. Lesions of their preoptic area abolish maternal behaviours while its electrical and optogenetic stimulation enhances maternal responsiveness.
Aims: Our objective was to identify genes responsible for maternal adaptation of the central nervous system. Therefore, we compared gene expression on 10th postpartum day in the preoptic area of lactating rat mothers, mothers whose pups were taken away right after delivery (pup-deprived mothers), and mothers separated from pups on 7th postpartum day (3-day pup-deprived mothers).
Methods: To measure motivations of the rat mothers, we characterized their maternal responsiveness with pup-retrieval test, anxiety-like and depression-like behaviour with elevated plus-maze and forced swim test, respectively, in the three experimental groups. We dissected the preoptic area on the 10th postpartum day and performed RNA sequencing. We identified the genes, whose expression level showed significant alterations between the experimental groups.
Results: Pup-deprived mothers did not take care of pups and 3-day pup-deprived mothers showed impaired maternal responsiveness in the pup-retrieval test compared to lactating mothers. Pup-deprived and 3-day pup-deprived rat dams did not lactate. In addition, pup-deprived mothers showed elevated depression-like behaviour. After analysing the RNA sequencing results considering false discovery rate, we found 9 differentially expressed genes comparing lactating and pup-deprived mothers, 32 genes comparing lactating and 3-day pup-deprived mothers and 12 genes comparing pup-deprived and 3-day pup-deprived mothers.
Conclusion: We determined genes in the maternal preoptic area, whose expression is dependent on lactation and maternal responsiveness. These genes are involved in the maternal adaptation of the central nervous system and may be responsible for behavioural changes demonstrated by the mothers.
Doctoral School: Neuroscience
Program: Neuromorphology and Cell Biology
Supervisor: Árpád Dobolyi