Abstract
C. elegans produces motion in appropriate response to each chemicals, for example, the moving toward attractive chemicals and the avoiding of noxious ones. The animal also has associative learning ability, i.e., after conditioning of NaCl (a soluble attractant) without food chemotaxis changes as to avoid NaCl when it perceives NaCl. Recently, a new research paradigm of "learning" and "stress" by using C. elegans, such as actions of aging and oxidation stress on learning, has been started. Under such circumstance, we revealed stress responses by gamma-irradiation during associative learning of NaCl without food as follows: 1) disturbance in chemotaxis of NaCl is induced and 2) chemotaxis of benzaldehyde (a volatile attractant) does not change. Soluble and volatile chemicals are perceived by separate sensory neurons that respectively connect with multiple interneurons and motoneurons. However, since several interneurons connect with these sensory neurons, neuronal circuits with respect to chemotaxis of NaCl and benzaldehyde are partially overlapped. Therefore, although it is indicated that the change by irradiation is induced on some parts of the neuronal circuit of NaCl chemotaxis, the change has never been clarified. Then, we modeled the neuronal circuit of chemotaxis based on actual connections in order to find certain parts that are induced to change by irradiation. Through the computer simulation of the responses before and after irradiation, we tried to predict the change on the neuronal circuit. In this report, we will discuss the preliminary results.
