(a) Original trace representing the effect of hemin (0.01 µmol.L-1) on the FES-evoked relaxation in non-treated guinea-pig gastric fundus strips. (b) Original trace representing the effect of hemin (0.01 µmol.L-1) on the FES-evoked relaxation in treated guinea-pig gastric fundus strips.  – adding PgF2α (0.5 ηmol.L-1) to evoke contractile response. Incubation with hemin is for 20 min., with Vitamin E – 10 min. before hemin application. The responses of the strips to EFS were registered in the presence of atropine (1 µmol.L-1).