Effect of metabolic inhibition on sodium ion exchange in the ventral nerve cord of Melanoplus differentialis.

l. Radioisotopic studies with 22Na were conducted in vitro on nerve cords of the grasshopper Melanoplus differentialis. 2. The total uptake of 22Na by nerve cords is significantly decreased by the presence of 5 mM azide in the incubation medium. 3. Six components were extracted from desaturation curves of nerve cords, after which some residual radioactivity remained in the majority of cases. 4. The size of the third efflux component is decreased significantly and that of the fourth efflux component is increased significantly by metabolic inhibition during incubation. 5. It was concluded that the intact nerve cord of M. dzyeerentiulis actively absorbs Naf from the bathing medium.