What is it about?

This study was performed to investigate, in the developing rat brain, the effect of early-in-life administration of two different doses of exogenous MLT on behavioral (anxiety and memory) and electrophysiological (CSD analysis) aspects of brain function. Additionally, brain levels of malondialdehyde (MDA) and superoxide dismutase (SOD), both cellular indicators of redox balance status, were evaluated. We hypothesize that MLT differentially affects the behavioral and CSD parameters as a function of the MLT dose.

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Why is it important?

For the first time, we have documented, in the brains of developing rats, the differential, dose-dependent effects of MLT treatment on behavioral (anxiety and memory) and electrophysiological (spreading depression) aspects of brain function. Our data from the anxiety and memory tasks suggest an anxiolytic effect of the lower dose but not the higher dose of MLT (see Figures 3, 4). In addition, our CSD findings indicate that MLT may act differentially in the brain at low and high doses, decelerating and accelerating CSD propagation, respectively.


Based on the behavioral, electrophysiological, and biochemical pieces of evidence, we suggest that, in addition to the receptor-mediated MLT actions, MLT acts as an antioxidant when given in low doses and may act as a prooxidant when given in high doses, as occurred with CSD under treatment with ascorbic acid (Mendes-da-Silva et al., 2014). However, confirming this suggestion requires a more detailed evaluation of the redox imbalance in the brain. It is still uncertain whether this new effect of MLT can be extrapolated from the rat to the developing human brain (Vine et al., 2022; Reiter et al., 2023). However, the clinical evidence suggests that melatonin may improve sleep disorders, cognitive functioning (Sumsuzzman et al., 2021), and neonatal hypoxic–ischemic brain lesions (Cardinali, 2019). In addition, melatonin may benefit classical migraine patients (Ebert et al., 1999) and improve blood glucose levels in diabetes (Delpino et al., 2021). Interestingly, melatonin levels are reduced in some metabolic, cardiovascular, and neurological diseases (Cardinali, 2020). This evidence suggests a possible relevant implication of our novel findings in the developing rat brain.

Professor Rubem C. A. Guedes
Universidade Federal de Pernambuco

Read the Original

This page is a summary of: Effect of neonatal melatonin administration on behavioral and brain electrophysiological and redox imbalance in rats, Frontiers in Neuroscience, October 2023, Frontiers,
DOI: 10.3389/fnins.2023.1269609.
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