Results S1

Comment on reversibility We and others have observed differences in the reversibility measured by the QPatch instrument and by manual patch clamp: washout of lipophilic compounds is delayed in the QPatch. The probable reason for this is the presence of unrecorded cells within the chip. One major difference as compared to manual patch clamp is that QPatch does not allow continuous flow of extracellular medium. It is hypothesized, that because each chip contains about a thousand unrecorded cells attached to the chip surface besides the single recorded one, lipophilic compounds saturate the membrane phase of un-recorded cells, from which the drug may leak even after removal of the drug-containing extracellular solution. Reversibility nevertheless is an additional parameter that can be used for exploration of different types of SCIs, most probably it reflects the lipophilicity of the compounds.