Fig. 3
From: Cranial radiation disrupts dopaminergic signaling and connectivity in the mammalian brain
Cranial irradiation prolongedly reduces both the number of dopamine neurons with spontaneous activity and dopamine neuron density within the ventral tegmental area (VTA). (A) We used a cells/track technique to evaluate the numbers of dopamine neurons with spontaneous firing at 1 day, 3 days, 7 days, and 28 days after irradiation. The decrease persisted for 4 weeks after radiation exposure (one-way ANOVA, F(4,67) = 7.626, P < 0.001; sham control: 1.72 ± 0.17, n = 18 tracks; day 1: 2.11 ± 0.24, n = 18 tracks; day 3: 1.08 ± 0.19, n = 12 tracks; day 7: 0.85 ± 0.22, n = 13 tracks, P < 0.05 vs. sham control; day 28: 0.82 ± 0.18, n = 11 tracks, P < 0.05 vs. sham control; 5 rats were used in each groups). (B and C) Radiation significantly changed the numbers of tyrosine hydroxylase (TH)-positive neurons within VTA (sham control: 62.59 ± 2.55, n = 17 slices from 5 rats; day 7: 44.00 ± 1.89, n = 12 slices from 5 rats; t test P < 0.01) but not in the substantia nigra (SN) (sham control: 35.88 ± 1.50, n = 16 slices from 5 rats; day 7: 35.83 ± 1.53, n = 12 slices from 5 rats; t test P = 0.98). *P < 0.05; **P < 0.01