Figure 8.

XE991 increases the excitability of whole hepatic portal veins. (a) Examples of isometric tension recordings in the absence and presence of (i) 10 μM XE991 and (ii) 50 μM linopirdine. Upward deflections represent spontaneous increase in tone. XE991 was applied at the downward arrow and was present for the remainder of the trace. (b) Bar chart showing the mean contraction interval in the absence (solid bars) and presence of two KCNQ channel blockers (hatched bars). The 10 μM XE991 (n=5 tissues) and 50 μM linopirdine (n=3 tissues) both significantly (P<0.001) reduced the interval. (c) Application of 10 μM XE991 in the presence of 5 mM4-AP still resulted in a reduction of the mean contraction interval (^***P<0.001).