(A) To displace the membrane potential, the holding current (dotted lines) was shifted to negative (−600 to −1000 pA) or positive (+800 to +1200 pA) values in the middle of a burst firing (200 ms from the onset). The traces are from a single cell.
(B) At the last trough of oscillatory bursting, membrane potential and time from burst onset were measured to examine their relationships. Burst width (i.e., time from burst onset to the last trough) was not significantly affected by changes in membrane potential (n=4; p>0.2, one-way repeated measures ANOVA). Each connected line represents one cell. Circle, no current; triangle, negative current; square, positive current.
(C) Low dose (0.2 µM) of NBQX shortened burst width in a reversible manner. The traces are from one cell.
(D) The mean reduction of burst width is 65.5±7.9% (n=4; **, p<0.01, paired t-test). In three cells, reversibility of NBQX was examined (94.6±10.3% of pre-NBQX value; p>0.5, t-test between Control and Wash). The recovery of burst width was significant (*, p<0.05, t-test between NBQX and Wash). Each connected line represents one cell.