FIG. 3.

The tyrosine receptor kinase (Trk) receptor inhibitor K252a depresses excitability in both Control and Axotomized neurons. A₁: response of a Control neuron treated with K252a to a depolarizing current pulse on Day 1. A₂: response of the same Control neuron on Day 2. There was a decrease in the number of spikes elicited. B₁: response of an Axotomized neuron treated with K252a to a depolarizing current pulse on Day 1. B₂: response of the Axotomized neuron on Day 2 (24 h after axotomy). The neuron did not exhibit the hyperexcitability typically observed after axotomy. C: change in number of spikes from Day 1 to Day 2 in Control and Axotomized groups. Both groups exhibited decreased excitability; the difference between the groups was not significant.