TRPV4 and overactive bladder: However, importantly, the quantity of ATP released by TRPV4 agonist in OAB samples was greater than that in control bladders; the peak ATP level and the net increase in ATP release were much higher from the overactive bladders (peak ATP levels, ρmoles/g tissue/min; OAB, 693 ± 239 (n = 6) vs. control, 190 ± 98 (n = 14), P < .05; net increase: OAB, 190 ± 98 (n = 6) vs. control, 88 ± 49 (n = 14), P < .05, Figure 12C).