3B and C). These effects were also observed after application of guanfacine. When guanfacine was washed out from the medium, the
speed of interneuron migration significantly increased and gradually reached control values (P < 0.01 at the first time interval after the drug wash when comparing guanfacine vs. no-wash medetomidine, one-way anova, Tukey’s multiple comparison test; Fig. 3C). Interestingly, we observed that although the migratory speed of GAD65-GFP+ cells was gradually restored during the removal of either medetomidine or guanfacine, the directionality of GAD65-GFP+ cells was modified by adra2 stimulation (Fig. 3B). Quantification revealed that during Selleckchem Cetuximab the washout period a significant proportion of GAD65-GFP+ cells modified their directionality following medetomidine or guanfacine application. The percentage of GAD65-GFP+ interneurons that made directionality changes in the range > 120–180° after the medetomidine wash or the guafancine wash was significantly increased compared to control GAD65-GFP+ interneurons (P < 0.01 for guanfacine compared to control click here and P < 0.05 for medetomidine vs. control, one-way anova Tukey’s multiple comparison
test; Fig. 3D), suggesting that adrenergic stimulation of cortical interneurons may alter their responsiveness to guidance cues. To determine whether cortical interneuron migration is altered in adra2a/2c-ko mice, we analysed the cortical distribution of GAD65-GFP+ interneurons before at postnatal day 21 in GAD65-GFP mice and in adra2a/2c-ko GAD65-GFP mice. Quantification revealed that the distribution of GAD65-GFP+ cortical interneurons in the somatosensory cortex was significantly altered in adra2a/2c-ko mice (n = 6) compared to the
control mice (n = 6; P < 0.05, χ2 test; Fig. 4). A significant increase in the percentage of GAD65-GFP+ cells was observed in upper cortical layers II/III in adra2a/2c-ko mice (P < 0.05, unpaired t-test), indicating that adrenergic receptors are necessary for the proper positioning of cortical interneurons in vivo. Quantification of the distribution of GAD65-GFP+ cells at P21 in the somatosensory cortex of adra2a-ko or of adra2c-ko mice was not significantly different from control GAD65-GFP+ mice (data not shown), suggesting that constitutive deletion of adra2a or adra2c during development may be compensated for by the presence of the other subtype. In this study we found that migrating cortical interneuron subtypes preferentially derived from the caudal ganglionic eminences express a specific pattern of adrenergic receptors and that pharmacological activation of these receptors affects the dynamic migration of cortical interneurons as they invade the developing cortical plate. Effects of adrenergic stimulation were most effective after adra2 stimulation, and they were concentration-dependent and reversible. Furthermore, effects of adra2 activation on the migration of cortical interneurons were significantly reduced in adra2a/2c-ko mice.