Neonatal handling alters the structure of maternal behavior and affects mother–pup bonding

• Published in: Behavioural brain research 2014-05, Vol.265, p.216-228
• Main Authors: Reis, A.R., de Azevedo, M.S., de Souza, M.A., Lutz, M.L., Alves, M.B., Izquierdo, I., Cammarota, M., Silveira, P.P., Lucion, A.B.
• Format: Article
• Language: English
• Subjects: Age Factors; Analysis of Variance; Animals; Animals, Newborn; Attachment; Behavioral psychophysiology; Biological and medical sciences; Brain-Derived Neurotrophic Factor - metabolism; CREB; CREB-Binding Protein - genetics; CREB-Binding Protein - metabolism; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; Handling (Psychology); Male; Maternal Behavior - physiology; Maternal Behavior - psychology; Neonatal intervention; Neurotrophic signaling; Object Attachment; Odorants; Olfactory Bulb - metabolism; Olfactory learning; Olfactory system and olfaction. Gustatory system and gustation; Pregnancy; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats, Wistar; Sex Factors; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2014.02.036

•Neonatal handling affects maternal care and alters mother–pups relationship.•Handling desynchronizes mother–pup interactions by changing maternal behavior sequence.•Neonatal handling induces sex-dependent changes in the nest odor preference.•Handling affects CREB and BDNF levels in pup's olfactory bulb, in a sex-specific manner.•Results suggest a differential olfactory learning and preference for nest odor in pups. During early life, a mother and her pups establish a very close relationship, and the olfactory learning of the nest odor is very important for the bond formation. The olfactory bulb (OB) is a structure that plays a fundamental role in the olfactory learning (OL) mechanism that also involves maternal behavior (licking and contact). We hypothesized that handling the pups would alter the structure of the maternal behavior, affect OL, and alter mother–pup relationships. Moreover, changes in the cyclic AMP-response element binding protein phosphorylation (CREB) and neurotrophic factors could be a part of the mechanism of these changes. This study aimed to analyze the effects of neonatal handling, 1min per day from postpartum day 1 to 10 (PPD 1 to PPD 10), on the maternal behavior and pups’ preference for the nest odor in a Y maze (PPD 11). We also tested CREB's phosphorylation and BDNF signaling in the OB of the pups (PPD 7) by Western blot analysis. The results showed that handling alters mother–pups interaction by decreasing mother–pups contact and changing the temporal pattern of all components of the maternal behavior especially the daily licking and nest-building. We found sex-dependent changes in the nest odor preference, CREB and BDNF levels in pups OB. Male pups were more affected by alterations in the licking pattern, and female pups were more affected by changes in the mother–pup contact (the time spent outside the nest and nursing).