ИСТИНА

Caenorhabditis elegans is one of the most investigated organisms in the world. This nematode is continuously eating. While eating it is rhythmically defecating with the stable period of 45-50 seconds. The nervous system usually controls rhythmic behaviors, but the defecation program of C. elegans is a distinguished exclusion. A signal is generated and spread through the gut cells. Intestine cells release protons to the lumen, activating and recruiting muscle cells into the process that causes defecation. All signaling functions of this process is 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 suggest a new model organism Heterorhabditis megidis that is closely related to C. elegans but has bigger gut cells that are suitable for electrophysiological methods. By using microelectrode techniques, we have recorded rhythmical changes of membrane potential related to the defecation cycle in the gut cells of H. megidis isolated intestine preparation. Our study demonstrates that intestinal cycling in H. megidis is associated with unusual all-or-none hyperpolarization action potential with a fixed duration of about one minute and a period of up to 15 minutes and amplitude about 60 mV. In addition, it is shown that gut cells are closely electrically coupled via gap junctions.