Effects of intrathecal administration of bombesin-related peptides and morphine on scratching behavior.

Left panels show duration of scratching response and right panels show total number of scratching bouts for bombesin (A,B), GRP (C,D), NMB (E,F) and morphine (G,H). Mice were observed immediately after the intrathecal injections up to 1 h. Each value represents mean ± SEM (n = 6). Symbols represent different dosing conditions. An asterisk (*) represents significant difference from the vehicle controls (open bars; 0 µg) (P