Figure 6. Inosine activity is blocked by BK channel inhibition.

(A,B) The attenuation of SA by inosine was reversed by the large conductance Ca²⁺-activated potassium channel blocker iberiotoxin (IBTX, 100 nM, n = 7). The SK3 channel blocker apamin (100 nM, n = 7) and the K_ATP channel blocker repaglinide (10 μM, n = 8) did not prevent the attenuation of SA induced by inosine (**p < 0.01, **p < 0.001, Baseline versus Ino; *p < 0.05, Apamin versus Apamin + Ino, Regap versus Repag + Ino). (C) The attenuation of SA by the A_2B agonist BAY60-6583 (100 μM) was blocked by IBTX (100 nM, n = 5). Data are expressed as mean ± SEM, but with values normalised to drug alone, as opposed to baseline, as described in Methods.