STZ treatment enhances the membrane protein expression of P2X3Rs. (A) Total and (B) membrane expression of P2X3R proteins in DRGs of control and STZ-treated rats. The total P2X3R protein expressions were normalized with their respective ERK1. The low expression of ERK1 in membrane fractions suggests a minimal contamination of cytoplasmic P2X3Rs in protein samples. (C) The total expression of P2X3Rs did not change with STZ treatment. On the other hand, the expression of membrane P2X3Rs was significantly increased (*P < 0.05, n = 5). (D) Membrane/total ratio of P2X3R expression. The membrane expression of P2X3Rs was normalized to the total P2X3R expression in its respective rat group. The membrane/total P2X3R expression ratio in control rats was 18.1 ± 0.8% (n = 5) in control rats and was 33.6 ± 5.8% (n = 5) in STZ rats. The membrane expression of P2X3Rs was significantly enhanced with STZ treatment (P < 0.05).