The experimental design is illustrated at the top of the figure. Subjects that received bumetanide (BUM) or its vehicle (Veh) are shown in black and white, respectively. Groups given bicuculline (Bic) or its vehicle (Veh) administration are depicted as squares and circles, respectively. The y-axis depicts the change from baseline after BUM and bicuculline treatment (Post Drug), and 0, 1, 2, 3 hr after the application of capsaicin (Post Cap). The error bars depict ± SEM.