Figure 2.

Maintained expression and properties of BK channel currents in cerebral artery myocytes after SAH. (A) Representative BK single-channel recordings from inside-out membrane patches in the presence of 100 nmol/L free Ca²⁺. Closed state (C) and individual channel open states (O1 to O5) are included in each record. (B) Ca²⁺ and voltage sensitivity of BK channels in control (n=6 to 16 patches from 4 animals) and SAH myocytes (n=12 to 19 patches from 4 animals). Free Ca²⁺ concentration calculated for the ‘Zero' Ca²⁺ solution was <1 nmol/L. Open-state probability curves were obtained from Boltzman's fit of data. (C) BK channel densities shown as channel number per patch at +80 mV in control (n=25) and SAH cerebral myocytes (n=27). NS: P>0.05. (D) Current–voltage relationship of paxilline-sensitive currents in myocytes from control (open circles, n=5) and SAH rabbits (closed circles, n=6). (E) Summary of quantitative real-time PCR for α- and β₁-subunits of the BK channel, normalized to GAPDH. BK, large-conductance Ca²⁺-activated potassium; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; SAH, subarachnoid hemorrhage.