A) Diagram of expression pattern of p2rx3.2(4.0):gal4vp16;UAS:nsfB-mcherry (referred to as Ntr). Projection of axons indicated with closed arrow. Terminal field in hindbrain (plexus) labeled with open arrow. B) Epifluorescent image of 4 dpf Ntr with labeling as in A. Projections of axons indicated with closed arrow; plexus indicated with open arrow. Select images from a time lapse video of 4 dpf Ntr in 10 mM Met at B) 0 hr, B′) 5 hr, and B′′) 18 hr. Puncta along axons (arrowheads) was seen at 5 hrs. By 18 hrs, motile cells containing cellular debris (asterisks) were seen around the ganglia and axons. C) 4 dpf Ntr imaged before Met treatment and C′) after 3 hrs in 10 mM Met (arrowheads point to puncta in axons). Met was then washed out of the larva, followed by imaging at C′′) 5 dpf and C′′′) 6 dpf (arrowheads point to degenerating ganglia and axons; asterisks indicate red motile cells containing debris). Same fish imaged at each time point. D) Dose response of 4 dpf Ntr given fish water (control vagal ganglia labeled gX), D′) 1 mM, D′′) 5 mM, or D′′′) 10 mM Met overnight for 18 hrs, followed by imaging at 5 dpf. Arrowheads point to degenerating ganglia and axons; asterisks indicate debris. Anterior is to the left; dorsal is at the top. Eye and otic vesicle (OV) are outlined. Cranial sensory ganglia labeled gV, gVII, gIX, and gX in panels A,B; vagal ganglia labeled gX in panels C,D.