２種類の誘引物質の同時提示に対する線虫C. elegansの行動

In order to clarify the mechanism underlying the integration of multiple sensory stimuli in the neuronal network, the chemotactic responses of the nematode Caenorhabditis elegans to simultaneous presentation of water-soluble sodium acetate and an odorant diacetyl, which were sensed by different sensory neurons and integrated by common interneurons, were examined. The fraction of animals that gathered at the 0.7 M sodium acetate location was greater than that at the 0.1% diacetyl location in the presence of both attractants (p<0.05), although the chemotaxis indexes for 0.7 M sodium acetate and 0.1% diacetyl were similar in the presence of a single attractant. On the other hand, the fraction of animals that gathered at the 0.02% diacetyl location was greater than that at the 0.1 M sodium acetate location in the presence of both attractants (p<0.05), although the chemotaxis indexes for 0.02% diacetyl and 0.1 M sodium acetate were similar in the presence of a single attractant. These results suggest the existence of excitatory and/or inhibitory connections in the neuronal circuit for attractant selection, and that the efficacy of these connections may change according to the concentrations of both attractants. [Jpn J Physiol 55 Suppl:S157 (2005)]