Ebru AFŞAR
Kastamonu Medical Journal - 2026;6(2):120-126
Aims: The present work was designed to evaluate how alterations in serotonin (5 -hydroxytryptamine, 5 -HT), 5 -HT re ceptor subtype 2B (5 -HT2BR), and neuropeptide Y (NPY) are associated with body weight regulation in a rat model of brain insulin resistance (B -IR) that mimics the early pathological features of Alzheimer's disease (AD). Methods : B-IR was induced in rats t hrough intracerebroventricular (i.c.v.) administration of amyloid -beta?-?? oligomers at a dose of 2.5 nmol in a total volume of 10 muL. 5-HT concentrations were quantified in brainstem and hypothalamic samples, while hypothalamic levels of 5 -HT2BR and NPY were determined using enzyme -linked immunosorbent assay (ELISA) methods. Body weight variation for each animal was defined as the difference between post -experimental and initial measurements. Group comparisons were conducted using the Mann -Whitney U test, and statistical significance was accepted at p < 0.05. Results: Rats in the B -IR group showed a tendency toward increased 5 -HT levels in brainstem tissue compared to the control group (p > 0.05), whereas hypothalamic 5 -HT levels were significantly decreased i n the B -IR group compared to controls (p < 0.01); body weight was significantly reduced in the B -IR group compared to the control group (p<0.01). In addition, rats in the B -IR group showed a downward trend in hypothalamic 5 -HT2BR and NPY levels compared wi th the control group (p > 0.05 for both). Conclusion: These findings suggest that decreased hypothalamic 5 -HT levels in the B -IR group may be associated with the observed reduction in body weight. Additionally, the downward trends observed in 5 -HT2BR and N PY levels may also be related to this change.
