ИСТИНА

Abstract. Rhythmic behaviors are usually controlled by the nervous system, but the defecation program of C. elegans is a distinguished exclusion. About once per minute a signal is generated and propagates through the chain of gut cells recruiting a wave of muscle contractions that cause defecation. All signaling functions of this process are produced by endoderm cells without the participation of the nervous system. The small size of C. elegans cells impairs the use of standard electrophysiological methods. We propose a new model organism H. megidis to overcome this problem. It is closely related to C. elegans, but has a bigger gut cells suitable for electrophysiological studies. Our study demonstrates that intestinal cycling in H. megidis is associated with unusual all-or-none hyper-polarization action potential with a fixed duration of about one minute and a period of up to 15 minutes and amplitude about 60 mV.