Browsing by Author "Luarte, L."

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    Control of motivation for sucrose in the paraventricular hypothalamic nucleus by dynorphin peptides and the kappa opioid receptor
    (2024) Sandoval-Caballero, C.; Jara, J.; Luarte, L.; Jimenez, Y.; Teske, J. A.; Perez-Leighton, C.
    The dynorphin peptides are the endogenous ligands for the kappa opioid receptor (KOR) and regulate food intake. Administration of dynorphin-A1-13 (DYN) in the paraventricular hypothalamic nucleus (PVN) increases palatable food intake, and this effect is blocked by co-administration of the orexin-A neuropeptide, which is coreleased with DYN in PVN from neurons located in the lateral hypothalamus. While PVN administration of DYN increases palatable food intake, whether it increases food-seeking behaviors has yet to be examined. We tested the effects of DYN and norBNI (a KOR antagonist) on the seeking and consumption of sucrose using a progressive ratio (PR) and demand curve (DC) tasks. In PVN, DYN did not alter the sucrose breaking point (BP) in the PR task nor the elasticity or intensity of demand for sucrose in the DC task. Still, DYN reduced the delay in obtaining sucrose and increased licks during sucrose intake in the PR task, irrespective of the co-administration of orexin-A. In PVN, norBNI increased the delay in obtaining sucrose and reduced licks during sucrose intake in the PR task while increasing elasticity without altering intensity of demand in the DC task. However, subcutaneous norBNI reduced the BP for sucrose and increased the delay in obtaining sucrose in the PR task while reducing the elasticity of demand. Together, these data show different effects of systemic and PVN blockade of KOR on foodseeking, consummatory behaviors, and incentive motivation for sucrose and suggest that KOR activity in PVN is necessary but not sufficient to drive seeking behaviors for palatable food.
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    Increased BMI is associated with an altered decision-making process during healthy food choices in males and females
    (Academic Press, 2025) Larenas Barrera, Gabriela Paz; Luarte, L.; Kerr, B.; Ossandón, Tomás; Cortés Mora, Víctor Antonio; Baudrand Biggs, René; Pérez Leighton, Claudio
    Unhealthy diets (rich in calories, sugar, fat, and sodium) are a major cause of obesity. Why individuals struggle to make healthy food choices remains unclear. This study examined how body mass index, biological sex, and eating context influence food attribute perception, the food choice process, and the percentage of healthy food choices. In an online study, males and females with and without obesity (n = 910) rated food images for healthiness and tastiness and made food choices after prompts directing them to choose foods they considered healthy (healthy prompt) or to choose as they would in their daily lives (typical prompt), which aimed to model healthy and typical eating contexts. When foods were classified as healthy or unhealthy using nutritional labeling information, all participants rated healthy foods with larger healthiness ratings, but females rated healthy foods as healthier and tastier than males. Still, participants with obesity had fewer healthy choices (i.e., choosing the food with the largest healthiness rating) regardless of sex and prompt. Further, tastiness differences were more relevant than healthiness differences during healthy food choices among participants with obesity, and more so after the typical prompt. On the contrary, healthiness differences were more relevant among participants with healthy weight regardless of prompt type. Our findings highlight the importance of eating contexts in how individuals use their perception of food attributes during healthy food choices and suggest that increasing the presence of healthy prompts and perceived tastiness of healthy foods may promote healthy food choices among individuals with obesity.