Anxiety-like, novelty-seeking and memory/learning behavioral traits in male Wistar rats submitted to early weaning.
The most frequently used animal models of early weaning (EW) in rodents, maternal deprivation and pharmacological inhibition of lactation, present confounding factors, such as high stress or drug side effects, that can mask or interact with the effects of milk deprivation per se. Given these limitations, the development of new models of EW may provide useful information regarding the impact of a shortened period of breastfeeding on the endocrine and nervous systems, both during development and at adulthood. Using a model of EW in which lactating Wistar rat dams are wrapped with a bandage to block access to milk during the last three days of lactation, we have recently shown that the adult offspring presented higher body mass, hyperphagia, hyperleptinemia, leptin as well as insulin resistance, and higher adrenal catecholamine content at adulthood. Here, we used this EW model, which involves no pharmacological treatment or maternal separation, to analyze anxiety-like, novelty-seeking and memory/learning behavioral traits in the adult male offspring. To that end, animals were tested in the elevated plus maze, in the hole board arena and in the radial arm water maze. Except for an increased number of rearing events (a measure of vertical activity), no other behavioral differences were observed between EW and control animals. The contrasting behavioral results between the three EW models may be associated with differences in HPA axis function in the offspring at weaning, since it has been observed that bandaging does not affect corticosteronemia while maternal separation and pharmacological EW increase it.
Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Centro Biomédico, Universidade do Estado do Rio de Janeiro, Brazil; Laboratório de Fisiologia Endócrina, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Centro Biomédico, Universidade do Estado do Rio de Janeiro, Brazil.
Mabel Carneiro
MC
Fraga
Egberto Gaspar
EG
de Moura
Natália
N
da Silva Lima
Patrícia C
PC
Lisboa
Elaine
E
de Oliveira
Juliana Oliveira
JO
Silva
Sylvio
S
Claudio-Neto
Cláudio C
CC
Filgueiras
Yael
Y
Abreu-Villaça
Alex C
AC
Manhães
D000818:Animals; D001007:Anxiety / Q000523:psychology*; D005106:Exploratory Behavior; D008297:Male; D018782:Maze Learning; D008568:Memory; D023421:Models, Animal; D051381:Rats; D014886:Weaning
Anxiety; Early weaning; Learning; Memory; Motor activity; Novelty-seeking