Fig. 1. Application of cyclical mechanical intervention to the head by passive motion lowers blood pressure in SHRSPs and AT1R expression in SHRSP RVLM astrocytes.
a, Schematic of the experimental protocol to analyse the effects of PHM on blood pressure (BP) in rats. HR, heart rate. b,c, Time courses (b) and values on day 29 (c) of the MAP in WKY rats and SHRSPs that were treated either with daily PHM or anaesthesia only (SHRSP without versus with PHM: P = 0.1344 (day 15), P = 0.0110 (day 22), P = 0.0463 (day 29); WKY without versus with PHM: P > 0.9999 (day 15, day 22 and day 29) (b); P = 0.9739 (column 1 versus 2), P = 0.0046 (column 3 versus 4) (c)). n = 7 (each group of WKY) and n = 8 (each group of SHRSP) rats. d, Heart rate values on day 29 (P = 0.9650 (column 1 versus 2), P = 0.2362 (column 3 versus 4)). n = 7 (each group of WKY) and n = 8 (each group of SHRSP) rats. e, The relative heart weight (heart weight/whole body weight) measured on day 30 (P = 0.9866 (column 1 versus 2), P = 0.0152 (column 3 versus 4)). n = 10 (WKY, −PHM), n = 13 (WKY, +PHM), n = 10 (SHRSP, −PHM) and n = 14 (SHRSP, +PHM) rats. f, The 24 h (day 29 to day 30) urinary noradrenaline excretion (P = 0.9854 (column 1 versus 2), P = 0.0085 (column 3 versus 4)). n = 8 (each group of WKY), n = 16 (SHRSP, −PHM) and n = 13 (SHRSP, +PHM) rats. g,h, Micrographic images of anti-NeuN (blue), anti-GFAP (green) and anti-AT1R (red) immunostaining of the RVLM of WKY rats (g) and SHRSPs (h) that were either left sedentary (top) or treated with PHM (bottom) under anaesthesia (30 min per day, 28 days). The higher-magnification images (centre and right) show the areas indicated by dotted rectangles in the low-magnification images (left). The arrows point to anti-AT1R immunosignals that overlap with anti-GFAP, but not anti-NeuN, immunosignals in the merged images. Scale bars, 50 µm. Images are representative of three rats. i,j, Quantification of AT1R-positive neurons (i) and astrocytes (j) in the RVLM of WKY rats and SHRSPs that were either left sedentary or treated with PHM. A total of 50 NeuN-positive (NeuN+) cells and 100 GFAP-positive (GFAP+) cells was analysed for each rat (P = 0.9602 (column 1 versus 2), P = 0.9215 (column 1 versus 3), P = 0.9313 (column 3 versus 4) (i); P = 0.9455 (column 1 versus 2), P = 0.0004 (column 1 versus 3), P = 0.0002 (column 3 versus 4) (j)). n = 3 rats for each group. Data are mean ± s.e.m. Statistical analysis was performed using two-way repeated-measures analysis of variance (ANOVA) with Bonferroni’s post hoc multiple-comparison test (b) or one-way ANOVA with Tukey’s post hoc multiple-comparison test (c–f, i and j); *P < 0.05, **P < 0.01, ***P < 0.001; NS, not significant.