Fig. 6

Glutamate negatively influences THN migration.

(A) Following THNs along the MHB suggested a cell speed increase upon AMPA receptor block, whereas NMDA causes a speed decrease. CNQX and hexamethonium applied simultaneously produced no speed change in ventral tracks. Progress over time is indicated. Elapsed time is given at the top. Scale bar: 25 μm. See also S11 and S13 Videos. (B) Individual tracks (orange, dark blue) are represented after tracking and correction (cyan markers) in SIMI°BioCell. See also S12 and S14 Videos. (C) Migration speed analysis shows that blocking AMPA receptors increases speeds strongly in the ventral part of the MHB. NMDA produces the opposite effect again in the ventral region. Blocking AMPA and nicotinic ACh receptors simultaneously leads to an increase in THN speed in dorsal tracks, whereas in the ventral part, the effects outbalance each other. Control values from experiment shown in Figs 4D and 6C. Means ± SEM are plotted per 10% MHB bin. (D) Statistic analysis confirms that the effects on THN speeds by the glutamate system are confined mostly to the ventral part of the MHB; control values from experiment shown in Fig 4E. Bars are means ± SEM. Data depicted in the graphs can be accessed in S3 Data. ACh, acetylcholine; AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor; CNQX, 6-cyano-7-nitroquinoxaline-2,3-dione; Hexam, hexamethonium; MHB, midbrain-hindbrain boundary; MK801, dizocilpine; NMDA, N-methyl-D-aspartate; THN, tegmental hindbrain nuclei neuron.