The132th KARC Colloquium
| Date&Time | 22 October 2018(Mon) 13:30-15:00 |
| Place | Conference Room, 3F, Research Building 2, Advanced ICT Research Institute |
| Lecturer | Feeding, Nutrient Sensing in Flies and Mice |
| Speaker | Dr. Greg Suh KIST, Korea/New York University, USA |
| Abstract | Sugars in the natural environment can be detected through taste-dependent and taste-independent modalities. Taste-dependent modalities consist mainly of peripheral chemosensory neurons such as sweet taste receptors, which primarily detect the orosensory value of sugar (i.e. sweetness). Evidence of a taste-independent modality - a post-ingestive sugar sensor - that detects the nutritional value of sugar has been shown in insects and mammals. However, the identity of the post-ingestive sugar sensor and the mechanism by which animals respond to the nutritional content of sugar independently of orosensory value is unknown. My laboratory identified six neurosecretory cells in the Drosophilabrain that produce Diuretic hormone 44 (Dh44), a homologue of the mammalian corticotropin-releasing hormone (CRH), were activated by nutritive sugars and not by nonnutritive sugars. Flies in which the activity of these neurons or the expression of the Dh44gene was disrupted failed to select nutritive sugars over nonnutritive ones after periods of starvation. Notably, artificial activation of Dh44 receptor-1 neurons dramatically increased the rate of proboscis extension reflex (PER) responses, promoting food intake. This manipulation also resulted in frequent episodes of gut contraction and excretion. Together, we propose that the Dh44 system directs the detection, ingestion, and digestion of nutritive sugar through a positive feedback loop to continue consumption of nutritive sugar. Given its strong sequence homology, CRH and CRH-expressing neurons in the hypothalamus would offer similar functions in mammals. I will discuss the findings from our recent studies with mice. |
| Language | English |
| Admission | Free |
| Organizer | Motojiro Yoshihara, Researcher, Frontier Creative Research Laboratory, Frontier Creative Research laboratory, KARC, NICT |