Leptin and Other Hormonal Responses to Different Stress Levels: Implications for Stress-Induced Memory Deficits

Background: Leptin plays a critical role in the body’s response to stress, influencing both learning and memory processes. Objective: The study investigates the effects of different stimuli on memory retrieval along with associated changes in the levels of corticosterone, leptin and serotonin in the bloodstream of rats. Methodology: Twenty-four albino Wistar rats were divided into four groups, with six animals in each group: (i) Control group, (ii) Oscillation-exposed group, (iii) Rock music-exposed group and (iv) Immobilization-exposed group. The animals were exposed to 2h of rock music, oscillation, or immobilization stressors. Memory retention was assessed at 1h and 24h after the termination of the stressors using the water maze test and 24h food intake was also monitored. The animals were decapitated 24h after exposure to the stressors to measure serum levels of leptin, corticosterone, and serotonin. Result: Memory retrieval was impaired 1h after exposure to oscillation, rock music, and immobilization. Immobilization also impaired memory retrieval 24h after exposure, accompanied by increased serum corticosterone levels, while serum leptin and serotonin levels decreased in rats. The anorectic effect was more pronounced in the immobilization group compared to the rock music or oscillation groups. Conclusion: The reduction in serum leptin levels and memory deficits observed in animals decapitated 24h after immobilization suggests that an inadequate amount of endogenous leptin may contribute to stress-related memory disorders.