Figure 4
E2 effect on I A in PVN-RVLM neurons. A, representative images illustrate IA isolated in PVN-RVLM neurons from the oil-group (left) and the E2-group (right). The left inset indicates the voltage protocol used to isolate IA. The right inset indicates the reduction in IA by 4-aminopyridine (4-AP), the blocker of IA. B, Plots of IA current densities versus command step potentials. The current density was calculated by dividing the current amplitude of IA by cell capacitance. The E2 group (filled squares) displayed significant reductions in current densities of IA, compared to the oil-group (open squares). *P < 0.05. C, activation curve plotted with the mean normalized chord conductance (open squares for the oil-group and filled squares for the E2-group) and inactivation curve plotted with the mean normalized amplitude (open circles for the oil-group and filled circles for the E2-group). The curves were fitted with the Boltzmann equation. There were no significant differences in either the activation or the inactivation properties of IA. D, the maximal current density (at +25 mV step potential) was compared between the two groups. (a) In the E2-group, the maximal current density of IA significantly decreased, compared to that of the oil-group. When the differences between the two groups were compared according to subdivisions, a significant difference was detected only in the DC (b), not in either the PaV (c) or the PaPo (d). *P < 0.05. Insets in (b), (c) and (d) indicate the locations of the PVN-RVLM neurons used for IA recording in each subdivision. DC, the dorsal cap subdivision; PaV, the ventral parvocellular subdivision; PaPo, the posterior parvocellular subdivision.