Molecular investigations of BKCa channels and the modulatory β-subunits in porcine basilar and middle cerebral arteries.

Large conductance calcium-activated potassium (BKCa) channels are fundamental in the regulation of cerebral vascular basal tone. We investigated the expression of the mRNA transcripts for the BKCa channel and its modulatory β-subunits (β1–β4) in porcine basilar and middle cerebral arteries using reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR. Western blotting was used to detect immunoreactivity for the porcine BKCa channel α-subunit and β-subunit proteins. The BKCa channel α-subunit RNA and protein distribution patterns were visualized using in situ hybridization and immunofluorescence studies, respectively. The study verified that the BKCa channel α-subunit is located to smooth muscle cells of porcine basilar and middle cerebral arteries. The mRNA transcript for β1-, β2- and β4-subunit were shown by RT-PCR in porcine basilar and middle cerebral arteries. However, at the protein level, only, the β1-subunit protein was found by western blotting.