Biology subjects

Yonekura, T.

Publications and source records attributed to Yonekura, T..

3 recordsLinked to original sources

bioRxiv2022

Expectation for sweet taste changes peripheral glucose metabolism via basolateral amygdala

Anticipatory physiological responses to food were first reported by Ivan Pavlov a century ago but the associated neural mechanism is still ill-defined. Here, we identified two types of neurons in the basolateral amygdala (BLA), which are activated by sweetener (saccharin) or water after sucrose conditioning, representing expected sweet taste and unmet expectation, respectively. Saccharin-induced met-expectation of sweet taste enhances, while H2O-induced unmet-expectation deteriorates, glucose metabolism in peripheral tissues. Deletion of saccharin-responsive neurons in BLA impaired saccharin-induced increase in insulin sensitivity. Deletion of H2O-responsive neurons in BLA improved glucose intolerance by unmet-expectation. Saccharin- and H2O-responsive neurons had different gene expressions. Our data suggest that the gap between the expected incoming sugar and sweet taste is evaluated by distinct BLA neurons to control peripheral glucose metabolism. One-Sentence SummaryNeurons in the basolateral amygdala control blood glucose levels by comparing anticipated sugar intake and sweet taste

physiology↗

bioRxiv2021

A new mathematical model of phyllotaxis to solve the genuine puzzle spiromonostichy

The view is widely accepted that the inhibitory effect of existing leaf primordia on new primordium formation determines phyllotactic patterning. Previous studies have shown that mathematical models based on such inhibitory effect can generate most of phyllotactic patterns. However, a few types of phyllotaxis still remain unaddressed. A notable example is costoid phyllotaxis showing spiromonostichy, which is characterized by a steep spiral with a small divergence angle and is unique to Costaceae plants. Costoid phyllotaxis has been called a "genuine puzzle" because it seems to disagree with the inhibitory effect-based mechanism. In an attempt to produce a steep spiral pattern, we developed a new mathematical model assuming that each leaf primordium emits not only the inhibitory effect but also some inductive effect. Computer simulations with the new model successfully generated a steep spiral pattern when these two effects met a certain relationship. The obtained steep spiral matched the real costoid phyllotaxis observed with Costus megalobractea. We also found by the mathematical model analysis that the early phyllotactic transition in the seedlings of this plant can be explained by the SAM enlargement.

plant biology↗

bioRxiv2020

Activation of prodynorphin neurons in the dorsomedial hypothalamus inhibits food intake and promotes positive valence

The regulation of food intake is one of the major research areas in the study of metabolic syndromes such as obesity. Gene targeting studies have clarified the roles of hypothalamic neurons in feeding behaviour. However, our understanding of neural function under physiological conditions is still limited. Immediate early genes, such as activity-regulated cytoskeleton-associated protein (Arc/Arg3.1), are useful markers of neuronal activity. Here, we investigated the role of Arc/Arg3.1 gene-expressing neurons in the hypothalamus after refeeding using the targeted recombination in active populations method. We identified refeeding-responsive prodynorphin/cholecystokinin neurons in the dorsomedial hypothalamus that project to the paraventricular hypothalamic nucleus. Chemogenetic activation of these neurons decreased food intake and promoted positive valence. Our findings provide insight into the role of newly identified hedonic neurons in the process of feeding-induced satiety.

physiology↗