Figure 4.

The rbo TS mutation specifically blocks synaptic transmission. a, Representative series of EJP traces from the DLM evoked by 0.1 Hz brain or thoracic stimulation (arrow) during temperature shift from 25 to 37°C. The numbers indicate order of the evoked response. Response amplitudes are reduced slightly in both genotypes during the temperature shift but persist in wt (left) and fail in an abrupt manner in rbo (rbo^ts1/rbo²) mutants when evoked by brain stimulation (middle). However, rbo DLM EJP shows gradual loss when induced by direct-simulating DLM motor neuron (right). b, Representative series of TTM EJP traces from wt and rbo transgenic rescue [(rbo^ts1/rbo²; rbo-egfp/+ (left) and rbo (middle and right)]. The left and middle panels show EJP responses during temperature shift from 25 to 37°C, whereas the right shows the EJP recovery when temperature is returned to 25°C. Note the graded loss of EJP amplitude after shift to restrictive temperature (middle) and the graded recovery of EJP amplitude after shift back to permissive temperature (right). c, Reversible block of EJC in DLM NMJs in rbo mutants. Representative traces at 25°C (1), 36°C (2), and after return to 25°C (3) in both wt (left) and rbo (middle) mutants are shown. d, Quantification of EJC amplitudes; n = 5 for each genotype. e, Quantification of latency of DLM EJPs evoked by brain stimulation in wt and rbo mutants during temperature shift from 25 to 37°C. * and ** indicate significant (p < 0.05) and highly significant (p < 0.01) change, respectively; n = 5 for each genotype. The bars show the mean ± SEM. stim, Stimulation.