Kursa, M. | Search bioRxiv

bioRxiv2024

Hormetic curve of dietary mono- and disaccharide content determines weight gain, gut microbiota composition and cognitive ability in mice

Hormesis is defined as dose response phenomenon characterized by low-dose stimulation and high-dose inhibition (Calabrese & Mattson, 2017). To date, low doses of several stressors (intermittent fasting, caloric restriction or selected phytochemicals) have been shown to exert beneficial effects on health (Martin et al., 2006). In the present study, we aimed to determine hormetic factors in a series of diets used in mice. We found that animals fed high-sugar diet (HSD) or high-fat diet (HFD) containing relatively high amounts of mono- and disaccharides become obese compared to animals fed standard diet (STAND) or ketogenic diet (KD) containing low doses of these compounds. Underlying the observed metabolic phenotype may be changes in the composition of the intestinal microbiota, showing u-shaped features in selected species. It is noteworthy that a short-term dietary regimen of several weeks resulted in difficulties in achieving effective scores on a complex cognitive test based on spatial procedural acquisition in the HSD and HFD groups. Our data identify dietary mono- and disaccharide content (commonly known as sugars) as a critical hormetic factor with beneficial/harmful effects at multiple levels of body function.

neuroscience↗

bioRxiv2020

More than a feeling: central amygdala mediates social transfer of information about proximity of danger

To survive, an animal must adequately respond to challenges presented by the environment. Social animals can learn about danger from fear of conspecifics which allows them to avoid predation and other threats without costly, first-hand experience. However, it remains unclear as to whether animals can transmit specific information that helps an individual avoid harm or whether the transmitted social signals simply increase vigilance in a non-specific manner. Here we demonstrate that animals can select appropriate defensive strategies in a novel environment depending on cues from the conspecific and, using opsins targeted to behaviorally activated neurons, identify distinct neuronal circuits in the central amygdala (CeA) that are crucial for choosing a context-appropriate reaction. The identified circuits differ in molecular markers and patterns of connectivity. Thus, we show that social signals carry explicit information about proximity of danger, necessary for choosing a context-appropriate reaction, and that the choosing process is mediated by the CeA circuits.

neuroscience↗