Electrophysiological analysis of the temperature-sensitive paralytic Drosophila mutant, para^ts

Paralysis of flight in the temperature-sensitive Drosophila mutant para^ts was found to be dependent on the rate of heating (Fig. 2). The gradual nature of the onset of paralysis during the temperature elevation was revealed by recording the electrical responses of the thoracic flight muscle fibers, evoked by cervical stimulation (Figs. 3,4). A neural focus of the mutation was indicated by intracellular current injections into identified flight muscle fibers during paralysis (Fig. 5) and by electrical activity recorded from gynandromorph flies, mosaic for para^ts (Table 1). Recording from picrotoxin-treated flies excluded a previous explanation of paralysis by a temperature-induced augmentation of GABAergic inhibition (Fig. 6). Under the same treatment, evidence was presented for a heterogeneous increase of excitation threshold for spike generation in certain neurons.