Tumor Necrosis Factor Alpha Inhibits L-Type Ca²⁺ Channels in Sensitized Guinea Pig Airway Smooth Muscle through ERK 1/2 Pathway

Figure 4

The Ba²⁺ current reduction induced by TNF-α is not mediated by a synthetic pathway activation in guinea pig tracheal myocytes. Ba²⁺ current evoked by step depolarization from −60 to 50 mV in tracheal cells from nonsensitized guinea pigs added with fetal bovine serum (NS + FBS, ) were significantly diminished when myocytes were grown with TNF-α (). Neither actinomycin D (Act D, ) nor cycloheximide (Cyclohex, ) addition during myocyte growth altered TNF-α induced effect on the Ba²⁺ current. Inset represents original recordings. , , when compared with TNF-α group. Symbols represent mean ± SEM.