Fig. 11.

Exposure to 1S,3R-ACPD ultimately reduces the delay to onset of repetitive firing in response to sustained depolarizing current injection. Before application of 1S,3R-ACPD, a depolarizing current injection rapidly shifted voltage from the resting potential (−74 mV, indicated by the dotted line) to a slowly rising plateau from which an action potential was eventually generated. In the presence of 1S,3R-ACPD, a small positive shift in the resting potential resulted in initial generation of an action potential during the rapid depolarizing phase, but there was a long delay until the next action potential. After removal of ACPD (2 min wash) the delay to firing was completely eliminated, and the neuron fired steadily during the depolarizing current injection. Note that the response to the hyperpolarizing current injection (−80 mV, indicated by the second dotted line) was not altered during or after exposure to 1S,3R-ACPD. Records are representative of seven neurons that were similarly examined.