BEHAVIORAL AND ELECTROPHYSIOLOGIC RESPONSES OF DROSOPHILA-MELANOGASTER TO PROLONGED PERIODS OF ANOXIA

Sensitivity to anoxia varies tremendously among phyla and species, Mos t mammals are exquisitely sensitive to low concentrations of inspired oxygen, while some fish, turtles and crustacea are very resistant, To determine the basis of anoxia tolerance, it would be useful to utilize a model system which can yield mechanistic answers, We studied the fr uit fly, Drosophila melanogaster, to determine its anoxia resistance s ince this organism has been previously studied using a variety of appr oaches and has proven to be very useful in a number of areas of biolog y, Flies were exposed to anoxia for periods of 5-240 min, and, after 1 -2 min in anoxia, Drosophila lost coordination, fell down, and became motionless, However, they tolerated a complete nitrogen atmosphere for up to 4 h following which they recovered, In addition, a nonlinear re lation existed between time spent in anoxia and time to recovery, Extr acellular recordings from flight muscles in response to giant fiber st imulation revealed complete recovery of muscle-evoked response, a resp onse that was totally absent during anoxia, Mean O-2 consumption per g ram of tissue was substantially reduced in low O-2 concentrations (20% of control), We conclude from these studies that: (1) Drosophila mela nogaster is very resistant to anoxia and can be useful in the study of mechanisms of anoxia tolerance; and (2) the profound decline in metab olic rate during periods of low environmental O-2 levels contributes t o the survival of Drosophila. (C) 1997 Elsevier Science Ltd.