Fig. 6. Effects of genistein, a selective tyrosine kinase antagonist. (A) Two control responses to 10 µmol l^-1 levamisole (Lev) and two responses in the presence of 90 µmol l^-1 genistein. Notice that the responses in the presence of genistein are smaller than the control responses. (B) Two control responses to 10 µmol l^-1 acetylcholine (ACh) and two responses in the presence of 90 µmol l^-1 genistein. The effect is a small, statistically significant reduction in the size of the peak (see Table 1).