Gestational physical exercise prevents early-life behavioral impairments in the offspring of a rat model of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a developmental condition characterized by symptoms of inattention, hyperactivity, and impulsivity. Spontaneously hypertensive rats (SHRs) comprise an ADHD rodent model that exhibits behavioral impairments recapitulating phenotypes observed in humans. SHRs further develop dopaminergic hypofunction in frontostriatal circuits and an imbalance in dopamine and norepinephrine systems. Maternal physical exercise, such as swimming, during pregnancy was shown to enhance offspring angiogenesis and neurogenesis, and to improve memory in rodents. Herein we determined the impact of gestational swimming on behavioral and dopaminergic parameters in childhood (1-2 week-old rats) and adolescence (4-5 week-old rats) of SHR and Wistar Kyoto rats (WKYs), used as a control group. The results showed that gestational swimming prevented neurodevelopmental impairments in behavior, assessed by the righting reflex and olfactory recognition tests, in the offspring. Furthermore, during adolescence, SHRs from exercised dams exhibited reduced novelty-seeking behavior, an important behavioral trait during this developmental period. Finally, D₂R and DAT mRNA content was reduced in the frontal cortex of adolescent SHRs whose mothers were exercised. Results indicate that gestational exercise could be an effective preventative strategy against ADHD-associated behavioral and molecular phenotypes in the offspring.