Related Experiment Video
Updated: Aug 14, 2026
Assessing Activity-based Anorexia in Mice
Published on: May 14, 2018
Nutritionally small-for-dates rats: their subsequent growth, regional brain 5-hydroxytryptamine turnover, and
Insights
Nutritional growth restriction in rats impacts brain development and behavior. Early restriction (fetal and neonatal restriction) caused brain weight deficits, while later restriction (infantile restriction) showed greater deficits in specific brain regions and altered adult behavior.
Area of Science:
- Neuroscience
- Developmental Biology
- Nutritional Science
Background:
- Nutritional growth retardation can affect brain development.
- Understanding the long-term consequences of early-life undernutrition is crucial.
Purpose of the Study:
- To investigate the effects of different timing of nutritional growth retardation on rat brain development and adult behavior.
- To compare the impact of fetal and neonatal restriction (FNR) versus infantile restriction (IR) on brain regions and neurotransmitter systems.
Main Methods:
- Rats were subjected to FNR (conception to 5 days postnatal) or IR (5 to 25 days postnatal).
- Brain weights of cerebellum, midbrain, and cerebrum were measured at 20 weeks.
- Turnover of 5-hydroxytryptamine in the hippocampus was assessed.
- Behavioral tests, including open field exploration and response to a loud noise, were conducted.
Main Results:
- FNR and IR groups showed reduced brain weights compared to controls, with IR having greater deficits in cerebellum and midbrain.
- Hippocampal 5-hydroxytryptamine synthesis rate was significantly faster in both FNR and IR groups.
- Undernourished rats exhibited reduced venturesomeness in the open field and prolonged freezing behavior after a loud noise stimulus.
Conclusions:
- The timing of nutritional growth retardation influences the extent of brain weight deficits.
- Early-life undernutrition leads to altered neurotransmitter turnover and behavioral changes in adulthood.
- These findings provide insights into the long-term neurological and behavioral consequences of growth restriction.
Abstract:
Rats were subjected to nutritional growth retardation either from conception to 5 postnatal days of age (fetal and neonatal restriction (FNR) group), or from 5 to 25 postnatal days of age (infantile restriction (IR) group). The FNR group may serve as a model for the human small-for-dates baby. At 20 weeks of age cerebellum, midbrain, and cerebrum were significantly reduced in weight by 4%, 5%, and 4%, respectively, in FNR animals when compared with controls. Only cerebellum and midbrain were affected in IR rats of the same age, but in both regions the percentage deficits (8% and 9%, respectively) were greater than in FNR animals. Both cerebellum and midbrain weighed significantly less in IR than in FNR rats. The timing of nutritional growth retardation appeared to be of little consequence to the regional brain turnover of 5-hydroxytryptamine in adulthood. The rate of synthesis in the hippocampus of both FNR and IR animals was significantly faster (67% and 75% respectively) than in controls. The increased turnover could perhaps represent "overactivity" of those 5-hydroxytryptaminergic neurons terminating in the hippocampus. Some differences in the behavior of the previously undernourished adult animals were also evident. On the fifth day of testing, control rats were most venturesome in the open field. Eighteen control rats left the edge zone within 2 min, whereas only 8 FNR and 11 IR rats did so. Most animals froze immediately after a 7-sex exposure to a loud electric bell. The delay before moving about again differentiated the three groups. FNR rats took longest to move out of the area in which they froze.
