Sham trained males were kept alone in the mating chamber for the first hour then paired with a tester. Memory index is calculated by dividing CI at test by the mean of sham CIs ; CItest/mCIsham. If memory index = 1, it indicates that there has been no learning since the courtship level of trained males is equivalent to that of sham trained males. $20 males were tested for each condition. For experiments using intact females, a male was paired with a female in a slit-cell chamber under white lights or dim-red lights and latencies of courtship and copulation, time lags until the first courtship performance or the successful copulation, were recorded. A latency value 1800 sec was given when no courtship or copulation was performed during 30 min (+)-JQ1 observation. 24 males were tested for each genotype and experimental condition. When introducing pheromone extracts, a two-part chamber with a fine nylon mesh was used to block direct contact with the pheromonecontaining filter paper. In order to collect female pheromones, a mature female was put on a wet filter paper in a chamber for to transfer odors to the filter. For the experiment using female pheromone deposits inside a large chamber, three intact females were introduced and kept for 10 min before the test then discarded before introducing a test male and a decapitated silent female. Shaker K + channels represent an important model system for OTX015 Epigenetic Reader Domain inhibitor studying the molecular basis of how inactivation is coupled to activation and recovery. Most of our knowledge of Kv channels comes from voltage clamp studies on the Shaker K + from Drosophila and its mammalian homologs. The recent determination of the crystal structure of the mammalian Shaker Kv1.2 channel-b subunit complex by MacKinnon and collaborators provides for the first time the possibility to clarify relationships between ion channel structure, molecular biophysics, and in vivo function. One important feature of the Kv1.2 structure is that it includes the intra-cellular domain preceding the trans-membrane domains. Namely, before the S1 helix from each of the four channel subunits, the N terminal domains come together to form the tetrameric T1 domain that has been shown to mediate voltage sensitivity. This domain is located directly under the pore entrance and as clearly shown in the structure together with the S1-T1 linker forms the pathways through which not only the flow of K + ions takes place, but also the channel N terminal peptide, which function as an inactivation mechanism in some Shaker family channels, can easily fit in. Fast N-type inactivation was first described in the context of Na + channels by Armstrong and Bezanilla ��ball and chain�� model.