Previous sections have described the following key observations concerning PACAP/receptor signaling in the LUT: (1) PAC1-immunoreactive fibers and neurons are present in the LUT including the urinary bladder and DRG (Braas et al., 2006); (2) PAC1 receptor is expressed by the DRG, urothelium, and detrusor smooth muscle (Braas et al., 2006); (3) PACAP increases detrusor contractions (Braas et al., 2006) and (4) PAC1 receptor antagonists, delivered intrathecally or intravesically, reduce voiding frequency in rodents with CYP-induced cystitis (Braas et al., 2006). This evidence concerns the gene ADCYAP1R1 and chronic cystitis.