Fig. 2.

Effect of dietary Na⁺ and K⁺ intake on BK channel α-subunit splice variant expression in single CCDs. Real-time PCR was used to examine expression of total BK α, stress-axis-regulated exon (STREX), and zero variant mRNA in single CCDs isolated from animals fed a HS or LS (A) or high-K⁺ (HK) or low-K⁺ (LK) (B) diet. Channel variant-specific mRNA abundance was normalized to that of 18S measured in the same sample and then normalized to the HS (A) or LK (B) ratio for that variant. A: expression levels of total BK α (n = 7), STREX (n = 7), and zero (n = 7) variant mRNA in CCDs isolated from HS-fed animals did not differ from those detected in LS-fed animals (n = 7, 7, 8, respectively). B: in contrast, CCDs isolated from animals fed a HK diet exhibited significantly greater mRNA abundance for total BK α (n = 9), STREX (n = 10), and zero (n = 9) variants than detected in LK-fed rabbits (n = 9, 9, 9, respectively). Values are means ± SE. *P < 0.03 compared with LK.