Related Experiment Video
Updated: May 19, 2026
A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
Early adult-onset undernutrition drives duration-dependent changes in locomotion, exploration and pain sensitivity in
Safae Hassab1, Zineb Hassab2, Ahmed Omar Touhami Ahami3
1Research Unit in Physiology and Physiopathology, Research Center for Genomics of Human Pathologies, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
Abstract:
Controlled dietary restriction, including calorie restriction and undernutrition, can modulate behavior and brain function; however, the effects of undernutrition initiated in adulthood and maintained over prolonged periods remain poorly understood. This study investigated how the duration of early adult-onset undernutrition differentially affects locomotor and exploratory behavior, responsiveness to dopaminergic blockade, and nociceptive sensitivity in rats. Starting at two months of age, animals were maintained at approximately 80 % of control body weight for 4, 25, and 32 weeks. Locomotor and exploratory activity were assessed in the open-field test. Dopaminergic responsiveness was evaluated using the D₂ receptor antagonist haloperidol, and nociceptive sensitivity was measured using the tail flick test after short- and long-term undernutrition. Undernourished rats exhibited domain- and duration-specific behavioral adaptations. Locomotor speed and distance increased early without a parallel rise in crossings, whereas crossings and exploratory rearing increased only after prolonged undernutrition. This dissociation became particularly evident under dopaminergic blockade: while haloperidol robustly suppressed locomotion at all stages, its inhibitory impact on exploratory behavior was diminished after prolonged undernutrition, consistent with selective adaptations in motivational and dopaminergic systems. In contrast, tail-flick latencies were reduced from early time points and remained stable thereafter, indicating an early and sustained increase in nociceptive sensitivity. Together, these findings demonstrate that early adult-onset undernutrition induces distinct temporal adaptations across behavioral domains, highlighting differential sensitivity of pain-related and motivational circuits to chronic energetic stress and the role of dopaminergic systems in shaping brain responses to prolonged undernutrition.
