Fig. 8. The protein tyrosine kinase inhibitor genistein (Gen; 0.1 mmol l^-1) if added to membranes with high levels of current (salt water) caused a significant inhibition (^**P<0.01, unpaired t-test) compared to vehicle controls. However, if the current was inhibited first by clonidine (Clon; ₂ adrenergic agonist, 1.0 µmol l^-1), genistein instead increased the current to an intermediate level (^*P<0.05). The inactive analogue daidzein (0.1 mmol l^-1) has no inhibitory effect (Marshall et al., 2000).