, 1982). In some cases, schizophrenia can result from a single rare but highly penetrant mutation (McClellan et al., 2007). hSK3Δ is a rare mutation and does not represent a common cause of the disorder (Bowen et al., 2001). Nonetheless, exploring the effects of rare mutations, such as hSK3Δ, on neural function provides considerable information that

could point to common cellular and circuit-level alterations underlying specific dimensions of the disease. The extent to which KCNN3 is involved in schizophrenia is currently debated ( Chandy et al., 1998, Cardno et al., 1999, Brzustowicz et al., 2000, Glatt et al., 2003 and Grube et al., 2011). Interestingly, in addition to being expressed in the ventral midbrain, KCNN3 is also highly expressed in the striatum and thalamus ( Köhler et al., 1996), two additional brain

RG7420 regions broadly linked to schizophrenia ( Grace, 2000 and Lisman, 2012). Further exploration of the impact of hSK3Δ expression in these brain regions will help to define how disease-related ion channel mutations may alter activity patterns or circuit function independently of dopamine neurons. It is important to note that reduced SK function is not the only route to altered dopamine firing patterns. This can also be achieved through developmental alterations in corticostriatal feedback loops to the VTA (Grace, 1991), reduced GABAergic transmission (Parker et al., 2011), or potentially through hypo-NMDA receptor-mediated suppression of GABAergic tone (Moghaddam et al., 1997). Our results suggest that therapeutics targeted toward normalization of dopamine activity patterns are likely to prove more Y-27632 supplier effective and have fewer side effects than current antipsychotics, which chronically suppress dopamine receptor signaling. All experiments were approved by the University of Washington Animal Care and Use Committee. Slc6a3Cre/+ (DAT-Cre) Fazadinium bromide mice were as described (

Zhuang et al., 2005). TRPV1-DA mice were as described ( Güler et al., 2012). Male and female mice were used in this study. For details on viral injections, see Supplemental Experimental Procedures. Primary antibodies used were against TH (monoclonal, 1:1,000, Millipore), GFP (polyclonal, 1:1,000, Invitrogen), and HA (monoclonal, 1:1,000, ABM). Secondary antibodies (donkey anti-rabbit or mouse) were conjugated to DyLight488 or CY3 (1:200, Jackson Immunolabs). Dopamine neurons were identified by fluorescence. For electrophysiology solutions and additional information see Supplemental Experimental Procedures. Neurons were held at −70 mV in voltage-clamp mode and tail currents were evoked with a 500 ms depolarization to 0 mV. Apamin (300 nM, Tocris) was bath applied to a subset of neurons to block SK3 channels. Recordings were made in current-clamp mode; frequency, CV-ISI, and average waveforms were taken from a 2.5 min recording window. Neurons were held at −60 mV in ACSF with 0 mM Mg2+ containing picrotoxin (100 μM, Ascent Scientific).