FIGURE 2.
Decreased temporal summation and increased theta resonance and phase lead in ventral hippocampus. A, temporal summation is decreased in ventral versus dorsal dendrites. The difference is abolished in the presence of ZD7288 (ZD). B, left and right panels, impedance magnitude as a function of the input frequency in a ventral (left) or dorsal (right) distal dendrite before (black trace) and after 10 μm ZD7288 (red trace). Insets, histograms of resonance parameters. C, same as B for phase responses. rad, radian. D, Ih activation curves in ventral and dorsal dendrites, same dendrites as in B, showing a larger Ih current in ventral dendrites. Ih activation was blocked by ZD7288. Inset, histograms of Ih amplitude measured at −140 mV and −90 mV. E, HCN1 and HCN2 mRNA levels are similar in the dorsal and ventral hippocampus. F, Western blots demonstrate that HCN1 and HCN2 protein levels are increased in ventral versus dorsal hippocampus. *, p < 0.05; **, p < 0.01.