Fig. 4.

Action potentials elicited by depolarizing currents (duration, 93 msec). The neuron was cultured for 13 days from a 10-day-old rat. The neuron was probably serotonergic because of the response to 8-OH-DPAT. Arrow indicates the zero current level. The first action potential (marked by an arrowhead) was elicited by the depolarizing current of 150 pA and the second and third action potentials were activated by 170 pA and 190 pA currents, respectively. The resting potential was −71 mV. The whole-cell version of patch-clamp under constant current was used. The experiment was conducted at 32° C.