Fig. 2

Peripheral SNS activity is necessary for the effect of VTA activation on tumor growth. a Four groups of mice were included: two groups expressing DREADDs and two controls (injected with virus lacking the DREADD gene). Each of them was then treated with 6OHDA or vehicle. All four groups were injected with LLC cells and treated with CNO. After 14 days of VTA activation, the weight of the tumors was analyzed (P < 0.8825; Student’s t-test; mean ± s.e.m; NS not significant; n = 7, 8 in each group). Data are shown as fold change in tumor weights relative to the mean in the control group. Data represent two independent repeats. b Weights of tumors isolated from DREADDs-expressing mice and their controls (injected with virus lacking the DREADD gene) that were treated daily with CNO and injected (intraperitoneal) daily with Nadolol, or a vehicle starting the day of tumor cell injection (P < 0.4283; Student’s t-test; mean ± s.e.m; NS not significant; n = 5, 4 for vehicle and n = 9, 10 for β-blocker experiment). Data are shown as fold change in tumor weights relative to the mean of the control. Data represent two independent repeats. c Plasma samples of tumor-bearing, VTA-activated mice and their controls. Samples were analyzed for their corticosterone levels using a standard ELISA kit (P < 0.81; Student’s t-test; mean ± s.e.m; n = 8, 7). Data represent two independent repeats. d Noradrenaline levels measured by ELISA in the plasma (P < 0.89; Student’s t-test; mean ± s.e.m; n = 6, 7), e spleen (P < 0.16; Student’s t-test; mean ± s.e.m; n = 7, 8), f tumor (P < 0.107; Student’s t-test; mean ± s.e.m; n = 5, 6), and g bone marrow (P < 0.044; Student’s t-test; mean ± s.e.m; n = 6, 7) of tumor-bearing VTA-activated mice and controls (control virus+CNO). Data are represented as fold change between VTA-activated mice and controls, from two independent repeats. h Immunohistochemical staining for tyrosine hydroxylase (TH; red) in the bone marrow of tumor-bearing VTA-activated mice and controls (control virus+CNO) following 14 days of repeated CNO injections (blue: DAPI staining; scale bar, 100 μm). i Analysis of the percentage of TH-positive areas per field of view (P < 0.047; Student’s t-test; mean ± s.e.m; n = 6). Data represent two independent repeats