Fig. 4

trpm7 mutants are sensitized to MPP⁺. (A–H) Dorsal views of 5-dpf larvae of the indicated genotype, treated with 500 μm MPP⁺ or vehicle control as indicated. Individual panels show distinct groups of Th1 IR cells in the following brain regions: (A–D) pretectal diencephalon (group 7); (E–H) periventricular hypothalamus (group 13); and I and J) bar chart showing average numbers of Th1 IR-positive cells in each group (n=11 animals scored). In the untreated samples, the number of Th1 IR cells was significantly lower in mutants than controls in group 7 (control avg. +/- SEM: 44 +/- 2, mutant: 36 +/- 2; Two way ANOVA with Bonferroni post-hoc test, p<0.001).. In group 13, (control: 56 +/- 1, mutant: 51 +/- 2) there was not a significant difference in the number of Th1 IR cells between untreated controls and untreated mutants. In both groups, MPP⁺ treatment effected a larger reduction in the number of Th1 IR cells in mutants than in controls (group 7, control+MPP⁺: 39 +/- 2, mutant+MPP⁺: 17 +/- 2; group 13, control+MPP⁺: 53 +/- 2, mutant+MPP⁺: 37 +/- 3). In group 7 the effect of MPP⁺ in mutants was almost three times larger than in controls, and in group 13 it was over four times larger; in both groups, mutants were significantly more sensitive to MPP+ treatment than controls (p<0.001). (K and L) Dorsal views of dissected brains from (K) control or (L) trpm7 mutant larvae, processed to reveal th2 mRNA. The pre-optic area (group 3b) is outlined in white. (th2-positive cells: control: 14 +/- 1, n=9; mutant: 7 +/- 5, n=12; p<0.001). Scale bar in A=50 μm, applies to A-H. Scale bar in K, =100 μm, applies to K,L. (M) Schematic illustrating the numbering scheme of Th1 and th2 positive (outlined in black) neuron clusters where darkness indicates more ventral groups (1 olfactory bulb; 2 subpallium; 3–4 preoptic area; 5,6,11 diencephalon; 7 pretectum; 8 anterior paraventricular organ; 9 interior paraventricular organ; 10 posterior paraventricular organ; 12 posterior tuberal nucleus; 13 hypothalamus; 14 locus coeruleus; 15-16 medulla oblongata; 17 area postrema; see Table S1 for additional details)