Synaptic responses were abrogated by a combination of low-calcium aCSF (0.5 mM CaCl2, 3.5 mM MgCl2), picrotoxin, and the ionotropic glutamate receptor antagonist kynurenic acid (2 mM). In neuroblastoma N1E115 cells transfected with a TTX-resistant Nav1.6, sodium currents carried by the TTX-resistant Nav1.6r mutant were isolated by adding 1 μM TTX (Biotrend, Wangen/Zurich, Switzerland) to the bath. Current signals were recorded in whole-cell voltage-clamp mode at room temperature (21°C ± 1°C). Recordings were

sampled at 20 kHz (low-pass filter check details 5 kHz) using an Axopatch 200A amplifier in conjunction with a Digidata 1322A interface and pClamp10 software. For details on the measurement protocols and the solutions used, please refer to the Supplemental Experimental Procedures. Guide cannulae (MAB6.14, Microbiotech) were implanted into male Sprague-Dawley rats targeting the medial PFC, caudate-putamen, and NAc, as described in Pum Torin 1 solubility dmso et al. (2008). After 5–6 days of recovery, osmotic minipumps (Samaha et al., 2007) were implanted and used to deliver HAL (0.5 mg/kg/d; i.p.) over a period of 14 days. During the experiments a 100 mM K+ challenge was applied for 80 min by reverse dialysis, before the perfusion medium was changed back to aCSF.

HAL analysis was performed by LC-MS/MS with online extraction. DA and 5-HT analysis was performed by high-performance liquid chromatography with electrochemical detection (Pum et al., 2008). The accumulation of APDs in synaptic vesicles was assessed using a mathematical model based on the Fick-Nernst-Planck equation (Trapp et al., 2008)

(Zhang et al., 2010), as described in detail in the Supplemental Experimental Procedures. Properties of the test compounds given in Table 1 were estimated using ACD (ACD/LogD Suite version 10.04, 2007; Advanced Chemistry Development, Toronto), and therapeutic plasma levels for CPZ, HAL, CLO, and RSP were taken from Baumann et al. (2004). Statistical analysis was performed using MATLAB. Error bars indicate SEM unless otherwise indicated. To analyze the effects of treatment, PAK6 ANOVA was used. For single-group comparisons, unpaired t tests were applied. These tests were performed using built-in routines in MATLAB. We would like to thank Drs. Erwin Neher and Peter Uhlhaas for critically reading this manuscript and Katrin Ebert for expert technical assistance. This work was supported by the Erlanger Leistungsbezogene Anschubfinanzierung und Nachwuchsförderung ELAN Grant Nr. PS-08.09.22.2 and by the Interdisciplinary Center of Clinical Research (IZKF) in Erlangen (Project J5) (both to T.W.G.). E.M.W. was supported by a stipend from the Erlanger Leistungsbezogene Anschubfinanzierung und Nachwuchsförderung ELAN. The funders had no role in the study design, the data collection and analysis, the decision to publish, or the preparation of the manuscript.