Effects of NGEN on I
recorded from motor neuron-like NSC-34 cells. In (A), superimposed current traces obtained in the absence (left) and presence (right) of 10 μM NGEN. In these experiments, cells were bathed Ca2+-Tyrode’s solution which contained 200 nM iberiotoxin, 200 nM apamin and 1 μM tetrodotoxin. The I K(M) was elicited from -20 mV to different potentials which ranged from -50 to +10 mV with 10-mV increments. (B) Effect of NGEN on the averaged I-V relations of I K(M) in NSC-34 cells (mean ± SEM; n = 9-13 for each point). ■: control; □: 10 μM NGEN. Current amplitude was measured at end of each voltage pulse. (C) Voltage dependence of I K(M) conductance in the absence (■) and presence (□) of 10 μM NGEN (mean ± SEM; n = 8-12 for each point). Note that there is a leftward shift in the activation curve of I K(M) conductance during cell exposure to NGEN, although the slope factor remains unchanged.