Effects of different dark chocolate diets on memory functions and brain corticosterone levels in rats under chronic stress

Abstract

Introduction: Stress influences cognitive behavior adversely, whereas dark chocolate exhibits positive effects on memory processes. This study investigated the effects of different dark chocolate diets on various aspects of brain functions in rats under chronic stress Methods: Thirty-five rats were randomly allocated into five groups: control, stress, stress with different (compulsory, optional and restricted) dark chocolate diets. Latency, dark stay (DS) time and the number of entrance to the dark compartment were respectively evaluated as memory, memory consolidation and locomotor activity by passive avoidance test. Results: There were significant differences between initial latency and latency after 1 day in all groups. In the stress-compulsory and restricted dark chocolate diet groups, latency after 1 day increased significantly. Moreover, the DS time was not significantly higher in the stressed group than the control group. The DS time and number of entrance to dark compartment decreased significantly in the stress-compulsory dark chocolate diet group compared to the stressed group. Furthermore, the number of entrance to dark compartment was significantly higher for the stress- optional dark chocolate diet compared to those with the compulsory diet. Additionally, serum and hippocampal corticosterone levels, except in the frontal cortex, were significantly lower only in the stress-compulsory dark chocolate diet group compared to the stressed group. Conclusion: Different dark chocolate diets had various effects on brain functions under chronic stress. Respectively, the compulsory and optional dark chocolate diets had the best and least effects on brain function improvement. Only the compulsory dark chocolate diet could improve brain functions such as memory, memory consolidation and locomotor activity.

The protective effects of escitalopram on chronic restraint stress-induced memory deficits in adult rats

“…Therefore, different drug doses seem to usually affect locomotor activity in normal conditions but not under stress conditions. These paradoxical results may indicate the influence of treatment duration, drug consumption manner, drug dose and the type of behavioral tests (Kalantarzadeh et al, 2020;Kaminska and Rogoz, 2016).…”

“…The shuttle box (20 × 25 × 64cm) was used as the passive avoidance apparatus for measuring different aspects of cognitive functions, such as learning, memory, consolidation and locomotor activity (Kalantarzadeh et al, 2020). This apparatus had two identical light and dark compartments with sliding guillotine doors and a grid floor.…”

“…Also, the latency time of entry to the dark compartment was measured after 1 day (up to a maximum delay of 300s). The difference between the IL and latency after 1 day was interpreted as the occurrence of learning in the experiment (Kalantarzadeh et al, 2020;Radahmadi et al, 2015). Also, the total dark stay (DS) time was considered as either the memory consolidation or storage of new information.…”

“…Also, the total dark stay (DS) time was considered as either the memory consolidation or storage of new information. In addition, the number of entrances to the dark compartment was recorded as the locomotor activity (Kalantarzadeh et al, 2020;Shabani et al, 2012;Vohora et al, 2000).…”

Comparing the Therapeutic Effects of Crocin, Escitalopram and Co-Administration of Escitalopram and Crocin on Learning and Memory in Rats with Stress-Induced Depression

“…Subsequently, on day 28, the PA memory trial was conducted. Further details of the PA test were based on our previously published reports ( 18 , 24 ). The initial latency time to enter the dark compartment was recorded before inducing the electric shock.…”