Void volume was significantly increased in female and male control rats, male and female rats with chronic cyclophosphamide (CYP)-induced cystitis, and female rats with acute (4 h) CYP-induced cystitis (n = 6–8). After VEGF/VEGF receptor 2 (VEGFR2) signaling blockade with Ki-8751, void volume significantly increased in control female rats (P ≤ 0.01) and female rats with acute (P ≤ 0.05) and chronic (P ≤ 0.05) CYP-induced cystitis as well as in control male rats (P ≤ 0.05) and male rats with chronic CYP-induced cystitis (P ≤ 0.01). Values are means ± SE. *P < 0.05, **P < 0.01. ns, not significant.