ИСТИНА

Slow circadian сentral pattern generators (CPGs) can function within a single cell and depend on positive and negative autoregulatory feedback loops of transcription and translation. On the other hand, well studied CPGs for the “fast” rhythmical behaviours such as running, scratching are shown to be driven by neuronal networks while voltage gated channels in individual cells from these networks play crucial role in rhythm generation. Calcium wave CPG in the nematode Caenorhabditis elegans gut is a leading biological model for ultradian rhythms studies and the role of different cellular and molecular mechanisms underlying its function are currently under investigation. The small size of C.elegans intestinal cells complicated the use of classical electro-physiological approaches in this species. We introduced a different yet related to C.elegans nematode species (Heterorhabditis megidis) with noticeably bigger gut cells in order to facilitate electro-physiological studies in nematodes and to elucidate some intestine CPG features that are difficult to resolve in C.elegans. We show that intestine CPG cycling could be perturbed by shifting gut cells membrane potential, suggesting participation of plasma membrane voltage gated channels. At the same time, we demonstrate, that CPG cycling persist in experiments were membrane potential was continuously clamped at steady voltage levels, that excludes the involvement of plasma membrane voltage gated mechanisms by definition. We suggest that two distinct pacemakers, one based on plasma membrane channels and another based on intrinsic calcium release mechanisms coordinate intestinal CPG cycling.