Objective: We aimed to investigate the effects of ghrelin and its receptor GHS-R1a on the regulation of taste aversion-associated emotional memory. Methods: We studied the effect of selective and reversible inactivation of emotion-associated neurons on emotions processed by the local neuronal loop of the lateral amygdala and insular cortex. We used intraperitoneal clozapine-N oxide (CNO) injection, local brain microinjection, and taste aversion test. Results: Microinjection of ghrelin into the lateral amygdala blocked the acquisition of taste aversion memory in mice. However, microinjection of ghrelin did not affect memory consolidation. Adeno-associated virus (AAV) microinjection into the lateral amygdaloid nucleus blocked the acquisition of taste aversion memory in mice. Moreover, intraperitoneal injection of CNO inhibited taste aversion memory formation, altering the aversion index. Conclusion: Microinjection of ghrelin and AAV-CaMKII-hM4Di-2A-GHS-R1a-GFP into the lateral amygdala inhibited the acquisition of conditioned taste aversion in mice. The inhibition of the memory formation was achieved through the activation of growth hormone secretagogue receptor 1a (GHS-R1a).
Ghrelin, insular cortex, CNO, CTA, GI-DREADD System
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