Rat spinal cord slices were incubated at 35 °C for 10 min with 100 nM NPY, alone (control), with the dipeptidyl-peptidase IV inhibitors Ala-pyrrolidine-2-CN (Ala-Pyrr-2CN, 10 μM) or Ile-Pro-Ile (10 μM), or with a mixture of peptidase inhibitors (PI mix) consisting of Ala-pyrrolidine-2-CN, amastatin, captopril and thiorphan (all 10 μM). Slices were fixed and a Y1 receptor antibody was used for immunofluorescence. Y1 receptor neurons were counted in laminae I and II. ANOVA, p=0.0306. Holm-Sidak’s post-hoc test: *p=0.0166 compared to control.