BNP functions independently of GRPR. A, B) BNP (1 nmol, i.t.) induced comparable scratching behavior in WT and Grpr KO mice as shown in 10 min time-course (A) and total (B). n = 6. C, D) Co-injection of GRP inhibitor 77427 (100 nmol, i.t.) significantly blocked 1 nmol GRP-induced scratching behavior (C) while it had no effect on scratching behavior induced by 1 nmol BNP (D). n = 5. ***p < 0.001 versus saline, unpaired t test. E) BNP-induced scratching behavior did not differ between WT and Grp KO mice. n = 7–10. F, G) Comparison of scratching behaviors induced by i.t. injection of BNP and GRP as shown in 10 min time-course (F) and total (G). n = 7.