P2X3 receptor antagonism lowers arterial pressure in conscious spontaneously hypertensive (SH) rats. (a), Intra-venous infusions of a P2X3 receptor antagonist (AF-219, 1–8 mg/kg/h) showing dose-dependent responses in systolic blood pressure (SBP). Solid lines indicate the blood pressure responses and dotted lines the predicted PK value based on plasma sampling (see also Supplementary Fig. 5). (b), Comparison of the SBP responses induced with 8 mg/kg/h AF-219 i.v. in SH (n = 7) and Wistar rats (n = 7), and in SH rats before and after carotid body resection (CBR; n = 7). (c), the peripheral chemoreflex evoked pressor responses in SBP during infusion of vehicle and 0.5–8 mg/kg/h AF-219. Data from seven conscious radio-telemetered rats are mean ± s.e.m. One-way ANOVA Dunnett’s post-test. * P < 0.05, ** P < 0.01, *** P < 0.001.