Novel K V 7 ion channel openers for the treatment of epilepsy and implications for detrusor tissue contraction

Neuronal voltage-gated potassium channels, K 7s, are the molecular mediators of the M current and regulate membrane excitability in the central and peripheral neuronal systems. Herein, we report novel small molecule K 7 openers that demonstrate anti-seizure activities in electroshock and pentylenetetrazol-induced seizure models without influencing Rotarod readouts in mice. The anti-seizure activity was determined to be proportional to the unbound concentration in the brain. K 7 channels are also expressed in the bladder smooth muscle (detrusor) and activation of these channels may cause localized undesired effects. Therefore, the impact of individual K 7 isoforms was investigated in human detrusor tissue using a panel of K 7 openers with distinct activity profiles among K 7 isoforms. KCNQ4 and KCNQ5 mRNA were highly expressed in detrusor tissue, yet a compound that has significantly reduced activity on homomeric K 7.4 did not reduce detrusor contraction. This may suggest that the homomeric K 7.4 channel plays a less significant role in bladder contraction and further investigation is needed.