FIG. 3.

Increased AHR after long-term 4-OPA exposure. Analysis of AHR after nonspecific challenge in BALB/c mice following dermal and pulmonary exposure to 4-OPA. Mice received 4 days of dermal exposure (concentration indicated on graph) followed by four pulmonary challenges of 4-OPA (1%). Data presented represent nonspecific challenge with MCh. Bars represent means ± SE of 7 mice per group. Levels of statistical significance are denoted as *p ≤ 0.05 and **p ≤ 0.01 as compared with vehicle control (no dermal or pulmonary exposure to 4-OPA).