▶Subject: Regulation of feeding by peptide hormones in C elegans

▶Speaker: Prof. Leon Avery (Department of Physiology and Biophysics Virginia Commonwealth University)

▶Date: 4:00PM/October/18(Fri)/2013

 

▶Place: Auditorium(1F),Postech Biotech Center

*Abctract

C elegans is nematode that eats bacteria in rotting organic matter. It takes in bacteria by pumping the muscles of the pharynx.
A well-fed worm pumps its pharyngeal muscles when bacteria are present, but not when they are absent. This response depends on the pharyngeal MC motor neurons. A hungry worm, however, will pump even in the absence of food, and this pumping occurs even without MC.
We find that this MC-independent pumping depends on neuropeptide signals. We have identified the neuropeptides NLP-3, NLP-24, and NLP-3 and the neuropeptide receptor NPR-17. Based on their sequences and pharmacology, we believe that these gene products may be the endogenous opioid system in C elegans.
How do these peptides cause MC-independent pumping? Another peptide, DOD-6, is turned out during starvation, and we have evidence that DOD-6 can stimulate MC-independent pumping. DOD-6 is a small secreted peptide whose sequence resembles that of toxins that block potassium channels. Furthermore, we have evidence that synthetic DOD-6 can block the C elegans potassium channel EGL-36.
We propose that opioid peptides such as NLP-24 act on the receptor NPR-17 to stimulate production of DOD-6. DOD-6, by blocking EGL-36, excites neurons that stimulate MC-independent pumping.

▶Inquiry: Prof. Seung-Jae Lee(279-2351)