Figure 7.

DPKQDFMRFamide partially restores propensity for fictive locomotion. A, Diagram of restrained third instar wandering larvae attempting to crawl (arrow indicates direction of peristaltic wave of locomotor muscle contractions). The rhythm frequency (number of contractions per second averaged over consecutive 2 min time bins) during a 20 min recording period was examined in both intact (Ai) and semi-intact larvae (Aii). Bi, Rhythm frequency remained stable in pinned intact larvae (n = 6) but decreased steadily in semi-intact larvae following replacement of hemolymph with the hemolymph-like saline HL3 and, after 20 min, was significantly reduced (n = 20; p > 0.001). When hemolymph-like saline contained (5 × 10⁻⁶ m) peptide, the rhythm frequency in the semi-intact larvae was significantly higher than without peptide (n = 20; p = 0.002) and significantly lower than in intact larval preparations (p < 0.05). Bii, RNAi interference of either DPKQDFMRFamide-sensitive receptor mitigated the peptide-induced partial rescue of fictive locomotor activity. The fictive rhythm in genetic control lines was significantly higher than both UAS FR^MBO4659 × elav-Gal4 (p = 0.02) and UAS DmsR-2^MBO5984 × elav-Gal4 (p > 0.05). UAS and Gal-4 lines were combined because they were not significantly different at any time point (circle, n = 10; square, n = 5; triangle, n = 5). MH, Mouth hooks.