Chemosensory behavior of semi-restrained Caenorhabditis elegans.

A new behavioral assay is described for studying chemosensation in the nematode Caenorhabditis elegans. This assay presents three main characteristics: (1) the worm is restrained by gluing, preserving correlates of identifiable behaviors; (2) the amplitude and time course of the stimulus are controlled by the experimenter; and (3) the behavior is recorded quantitatively. We show that restrained C. elegans display behaviors comparable to those of freely moving worms. Moreover, the chemosensory response of wild-type glued animals to changes in salt concentration is similar to that of freely moving animals. This glued-worm assay was used to reveal new chemosensory deficits of the potassium channel mutant egl-2. We conclude that the glued worm assay can be used to study the chemosensory regulation of C. elegans behavior and how it is affected by neuronal or genetic manipulations. (c) 2005 Wiley Periodicals, Inc.