HNSCC induces neuronal P2X2/3 plasticity that is reversed by anti-NGF. a. Sustained ATP current (top panel) is enhanced and prolonged following SCC co-culture; anti-NGF added into the co-culture reduced the sustained ATP current. Transient ATP current (lower panel) is not affected by either co-culture or anti-NGF. b. Sustained ATP current density is increased by co-culture (One-way ANOVA), and is reversed by anti-NGF. c. Dot plot of sustained ATP current in different diameter neurons. Co-culture increased current in medium-sized TG neurons; this increased current was reversed by anti-NGF. d. Representative immunofluorescence images of P2X2 and P2X3 expression in TG neurons. e. HNSCC co-culture increased the percentage of neurons expressing P2X2 and P2X3 subunits. Anti-NGF treatment significantly reduced percentage of neurons expressing P2X3 but not P2X2 subunits. The significant increase in the percentage of neurons that express both subunits following co-culture was reversed by anti-NGF application (One-way ANOVA). f. P2X2 immunofluorescence intensity was not changed after co-culture or anti-NGF treatment. P2X3 immunofluorescence intensity was significantly increased following co-culture, and was reduced by anti-NGF (one-way ANOVA). g. In mice with tongue HNSCC, mRNA expression for P2X2 was increased, while P2X3 expression was unchanged in TG neurons (Student’s t-test).