Mother-pup interactions during a short olfactory deprivation period in young rats.

The effects of short-term bilateral naris occlusion (inducing olfactory deprivation) on mother-pup interactions, suckling behavior and hormonal status during post-natal development in Wistar rats were studied. Bilateral naris occlusion was performed on 8-day-old rat pups and its effects were evaluated at Day 9 and at Day 15. The narins opened spontaneously between Day 12 and 14. Olfactory-deprived pups exhibited a greater level of corticosterone at both ages versus untreated or sham animals. Olfactory deprivation via naris occlusion, in young rats, alters mother-pup interactions with a decrease in the duration of mother-pup retrieving and an increase in pup licking. Olfactory-deprived pups showed also a lower mean duration of nursing and a decrease in nipple attachment, which appeared related to difficulties in finding the nipple. Olfactory-deprived pups had difficulty recognizing their nest. These behavioral alterations were accompanied by a diminution in milk ingested and growth retardation associated with a reduced level of thyroxin at both 9 and 15 days of age.

Effects of early olfactory deprivation on novelty-seeking behavior and primary and secondary lymphoid organs in young rats.

The aim of this study was to investigate the effects of an early olfactory deprivation on novelty-seeking behavior and lymphoid organs during post-natal development in rats. Therefore, we performed a bilateral nasal obstruction on 8-day-old rats and we studied its effects at 21 days of age. Animals exposed to nasal obstruction presented an increased plasma corticosterone level, an adrenal hypertrophy more marked in females (+68% in females and +29% in males compared to sham group), a reduced growth of olfactory bulbs only in females (-43% compared to sham group) and an impaired novelty-seeking behavior, which seemed also more marked in females. Moreover, thymus specific weight and ConA-induced proliferative activity of thymocytes were diminished after induction of nasal obstruction in females but not in males. At last, spleen specific weight was not affected by nasal obstruction, although mitogen-induced proliferative activity of splenocytes was diminished in both sexes. These data showed that early olfactory deprivation by nasal obstruction was associated with some behavioral, endocrine and immunological alterations, which may have serious consequences for the health and the social status of the individuals.