Brain Serotonin 5-HT2α Receptor Density in Male Rats Can Be Affected by Bisphenol A and Passive Avoidance Learning

Abstract

Background: Bisphenol A (BPA) may adversely affect the nervous system. Objectives: This study aimed to assess the effects of passive avoidance learning on BPA-induced toxicity, as indicated by serotonin 5-HT2α receptor density in the cerebellum, basolateral amygdala, and hippocampus of male rats. Methods: Thirty male rats (200 - 220 g) were allocated to six experimental groups. BPA was administered orally for 15 consecutive days. Learning and memory performance were assessed using a passive avoidance shuttle-box paradigm. Serotonin 5-HT2α receptor density was evaluated by immunohistochemistry in the selected brain regions. Immunohistochemical labeling was quantified by measuring color parameters using image-analysis software. Results: BPA at both doses reduced 5-HT2α serotonin receptor density in the examined brain structures. Passive avoidance learning mitigated the toxic effects of BPA on 5-HT2α receptor density in these structures. Conclusions: Overall, BPA exposure downregulated 5-HT2α receptors in the hippocampus, amygdala, and cerebellum of male rats, whereas passive avoidance learning and memory were associated with an increased receptor density.