Modulatory effect of ionizing radiation on salt chemotaxis learning; The Role of G protein subunit in

Hamada, Nobuyuki*; Sakashita, Tetsuya; Ikeda, Daisuke*; Yanase, Sumino*; Suzuki, Michiyo; Ishii, Naoaki*; Kobayashi, Yasuhiko

Well-fed adult animals were exposed to cobalt-60 -rays, followed by the chemotaxis assay. A decrease in chemotaxis toward NaCl occurred only after combined starvation and exposure to NaCl. Irradiation led to an additional decrease in chemotaxis immediately after an acute dose in the transition stage of salt chemotaxis learning. Strikingly, chronic irradiation induced negative chemotaxis in the exposed animals, i.e., the primary avoidance response. Radiation-induced additional decreases in chemotaxis following acute and chronic irradiations were significantly suppressed in the mutant, which was defective in GPC-1 (one of the two subunits of the heterotrimeric G protein). The data suggest that radiation behaves as a modulator in salt chemotaxis learning via GPC-1 and a specific neuronal network, and may shed light on the modulatory effect of radiation on learning.