Anesthetic-resistant spontaneous mutant of drosophila melanogaster: intensified response to 60Cobalt radiation damage.

Accumulating evidence suggests that the extent of acute damage by ionizing irradiation is closely related to the state of membrane orderliness. Decreased orderliness apparently protects organisms from ionizing irradiation. Because anesthetics decrease membrane orderliness, anesthesia is expected to affect damages caused by ionizing irradiation. The present study compared the effects of 60Co irradiation on Drosophila melanogaster between an anesthetic-resistant spontaneous mutant and an anesthetic-sensitive strain. We have previously established an anesthetic-resistant mutant strain, Eth-29, of Drosophila melanogaster. Eth-29 is resistant to diethylether, chloroform and halothane. The anesthetic-resistant strain was found to be radiosensitive when evaluated by survival at the eighth day after irradiation or by dyskinesia (knock-down) at the second day. The results indicate that anesthetic resistance may be related to an increase in orderliness. The findings in reciprocal crosses between Eth-29 and the control strain indicate that the mechanism of survival is different from that of knock-down. Presumably, knock-down is the direct sequela of irradiation, and the present result suggests that membrane damage may be involved in inducing knock-down.