Fig. 2.

Dose-related apneic responses to Cap, PBG, and AITC in anesthetized, spontaneously breathing mice after pretreatments with TNF-α and its vehicle. Treatments were made 24 h before the experiments; Veh: intratracheal instillation of vehicle (PBS, 0.03 ml); TNF-α: intratracheal instillation of TNF-α (10 μg/ml, 0.03 ml). Apneic ratio was calculated as (apneic duration/20-breath average of baseline expiratory duration). Responses to Cap, PBG, and AITC were tested in different groups of mice; n = 6 in each group (except in the Veh group response to AITC, n = 5). Data are means ± SE. *Significantly different from lowest dose in each group (P < 0.05); †significantly different from corresponding data in the Veh group (P < 0.05).