Figure 9.

Effect of dendrotoxin on late-spiking neurons

A, firing pattern of a late-spiking neuron with a short 1st ISI (31.1 ± 5.2 ms, n = 4) in control solution (1) and in the presence of 200 nm dendrotoxin (2). B, plots of the ratio of the 1st ISI to the 2nd ISI in the absence and presence of dendrotoxin. Individual symbols represent the plots obtained from individual neurons. The dashed line indicates the ratio value of 1.0. C, whole-cell outward currents in control solution (1) and in the presence of 200 nm dendrotoxin (2) in a class I late-spiking neuron. C 3 shows a dendrotoxin-sensitive current obtained by subtraction of C 2 from C 1. Note that both inactivating and non-inactivating currents are sensitive to dendrotoxin. D, firing pattern in a late-spiking neuron with a long ISI (212.9 ± 24.2 ms, n = 4) in control solution (1) and in the presence of 200 nm dendrotoxin (2). E, plots of the ratio of the 1st ISI to the 2nd ISI in the absence and presence of dendrotoxin.