To first determine whether migrating GAD65-GFP+ interneurons expressed adrenergic receptors, we used FACS to isolate a population of GAD65-GFP+ cortical interneurons from cortical slices. To label and isolate excitatory pyramidal precursors using FACS, in utero electroporation of a TOM+-expressing plasmid in the ventricular zone of the dorsal pallium was performed at E14.5 (Fig. 1A). This method is widely used to specifically label excitatory pyramidal neurons in vivo (Chen et al., 2008). Electroporation

in the GAD65-GFP+ mice confirmed that TOM+ cells did not overlap with cortical interneurons LGK-974 chemical structure (Fig. 1A). Real-time PCR performed on amplified mRNA extracted from FACS-isolated GAD65-GFP+ cells revealed that GAD65-GFP+ cells expressed a pattern of adrenergic receptors: the alpha1d adrenergic receptor (adra1d), the alpha2a adrenergic receptor (adra2a), the alpha2c adrenergic receptor

(adra2c) and the beta1 adrenergic receptor (adrb1; Fig. 1B). None of the other adrenergic receptor subtypes were detected an the mRNA level (data not shown). Quantitative PCR did not reveal any major differences Pictilisib between the expressions of adrenergic receptors in FACS-isolated GAD65-GFP+ interneurons and TOM+ pyramidal neurons (Fig. 1C), indicating that adrenergic receptor numbers are not specifically raised in GAD65-GFP+ cortical interneurons. Among the four adrenergic receptors expressed in GAD65-GFP+ cells, adra2a, adra2c and adrb1 were expressed at higher levels than adra1d (Fig. 1D). To determine whether migrating interneurons could respond to adrenergic stimulation, we used time-lapse imaging of GAD65-GFP interneurons in cortical slices combined with pharmacological drug applications. Imaging of cortical interneurons was performed between E17.5 and E18.5. Migrating cortical interneurons Thymidine kinase located in the cortical plate and intermediate

zone were randomly selected and tracked initially during a control period of 95 min. After 95 min of time-lapse imaging, drugs targeting adrenergic receptors expressed in GAD65-GFP+ cells were applied to the bath medium and effects on migration were analysed. Using this slice assay, application of an adrb agonist (isoproterenol, 500 μm) did not significantly modify the mean speed of neuronal migration whereas application of an adra1 agonist (cirazoline 500 μm) and an adra2 agonist (medetomidine 500 μm) significantly reduced the mean migratory speed of GAD65-GFP interneurons (P < 0.01 for both drugs vs. control, one-way anova, Tukey multiple comparison test; Fig. 1, E1, E2–G and Movies S1 and S2). Application of cirazoline and medetomidine shifted the speed distribution of GAD65-GFP+ interneurons to lower migratory speeds and a greater proportion of cells migrating at < 15 μm/h were observed during exposure to medetomidine and cirazoline than during control conditions (Fig. 1G).