Figure 8.

Northern blot analysis: distinct effects of A23187 and TG treatment on Na⁺ channel α- and β₁-subunit mRNA levels in adrenal chromaffin cells. (A) Cells were treated with DMSO (−), 1 μM A23187 (+) or 100 nM TG (+) for up to 48 h; poly(A)⁺ RNA was extracted, separated by electrophoresis on agarose gel, and transferred to membrane. The membrane was sequentially hybridized to each ³²P-labelled cDNA probe for hNE-Na (top), rat brain β₁-subunit (middle), and GAPDH (bottom) after removal of the former probe. Data shown are typical one from three independent analyses with similar results. (B) Levels of α- and β₁-subunit mRNAs and GAPDH mRNA in (A) were quantified by a Bioimage analyser, and the relative amount of α- or β₁-subunit mRNA GAPDH mRNA⁻¹ in A23187- or TG-treated cells is shown. A value of 100% represents the relative level obtained in DMSO-treated cells at the left lane of each incubation time. Mean±s.e.mean (n=3). ^*P<0.05, compared with DMSO-treated cells.