Figure 2. Activation of mitoK_ATP channels increased the electrical coupling of directly coupled astrocytes in slice.

(A) Representative recordings of a recorded astrocyte pair after addition of DIZ, 5-HD, or both for 5 min. The coupling ratio was increased with DIZ but decreased with 5-HD. (B) Time course of changes in the electrical coupling ratio under the following conditions: control (n = 16), DIZ (n = 13), 5-HD (n = 8), DIZ+5-HD (n = 9), internal solution containing DIZ (IS + DIZ, n = 10), and internal solution containing 5-HD (IS + 5-HD, n = 8). The duration for each treatment was 10 min, followed by a 10-min recovery in control aCSF solution. The increased electrical coupling ratios, already apparent 3 min after exposure to DIZ, reached peak level at 5 min, and then lasted with little adaptation till the end of treatment. Blocking the astrocytic mito-K_ATP channel with 5-HD immediately inhibited electrical coupling, and after 10 min, the coupling was inhibited to 71% of the initial control level. The coupling ratio with DIZ/5-HD treatment was the same as that with control in the 10-min duration. Also, we did not find any difference in the coupling ratios between slices treated with an internal solution containing astrocytic mitoKATP channel modulator (DIZ or 5-HD) and the DIZ or 5-HD treated slices respectively, during the recording period (0 to 10 min). All the paired astrocyte recordings were obtained in P21–25 rats and from the CA1 stratum radiatum region. Mean ± SEM; * P<0.05 compared to the control. DIZ, Diazoxide; 5-HD, 5-hydroxydecanoate.