Sub-chronic Administration of Fearless Energy Drink Alters Hippocampal Expression of DRD2, COMT, and OPRM1 in Albino Rats

Abstract

Increasing consumption of energy drinks has raised concerns regarding their effects on neurobiological pathways involved in reward processing and addiction. This study evaluated the effect of sub-chronic administration of Fearless Energy Drink (FED) on hippocampal expression of dopamine D2 receptor (DRD2), catechol-O-methyltransferase (COMT), and mu-1 opioid receptor (OPRM1) genes in albino rats. Twenty-four adult albino rats were randomly assigned to four groups (n = 6). The control group received distilled water, while the treatment groups received FED orally at 7, 14, and 21 mL/kg body weight daily for 60 days. On day 61, hippocampal tissues were collected for gene expression analysis using quantitative real-time polymerase chain reaction (qRT-PCR). Relative gene expression was determined using the 2^-ΔΔCt method. FED administration altered hippocampal expression of all three genes. DRD2 expression was reduced in the low-, medium-, and high-dose groups, with fold-change values of 0.01, 0.02, and 0.61, respectively. COMT expression was also down-regulated across treated groups, with fold-change values of 0.005, 0.008, and 0.007. OPRM1 exhibited marked reductions, with fold-change values of 0.0002, 0.0018, and 0.0018 in the respective dose groups. Although all genes were down-regulated, the dose-response pattern was not consistently linear. Sub-chronic FED exposure was associated with down-regulation of DRD2, COMT, and OPRM1 expression in the hippocampus of albino rats. These findings suggest that prolonged energy drink consumption may influence gene-regulatory pathways linked to reward-related neurobiology. Further studies incorporating behavioural and protein-level assessments are warranted.