E2 effects on mRNA expression density of Kv channel subunits in single PVN-RVLN neurons. For relative quantification of Kv4.2 and Kv4.3 mRNA expression in the PVN-RVLM neurons between the oil- and the E2- groups, single-cell real-time RT-PCR was performed. A, the location of the PVN-RVLM neurons used for single-cell real-time RT-PCR in each subdivision. DC, the dorsal cap subdivision; PaV, the ventral parvocellular subdivision; PaPo, the posterior parvocellular subdivision. B, The mRNA expression density of the target genes of PVN-RVLM neurons was compared between the oil-group and the E2-group using the formula 2-ΔCt. C, the mRNA density of Kv4.2 and Kv4.3 was analyzed using the 2-ΔΔCt method and was finally expressed as n-fold that of the oil-group. The Kv4.2 significantly decreased, 0.54 ± 0.06 fold, in the E2-group (n = 21, *P < 0.05) compared to that of the oil-group (n = 19). However, Kv4.3 was not expressed differently between the two groups. The mRNA expression densities of Kv4.2 and Kv4.3 were compared in the three different subdivisions: the DC, the PaV, and the PaPo. In the DC, Kv4.2 mRNA expression significantly decreased in the E2-group, compared to that of the oil group, and decreased more dominantly than in overall expression. In the PaV and PaPo, no significant differences were detected. Kv4.3 mRNA expressions were not statistically different between the two groups for any subdivisions.