Introduction: A growing body of evidence points to the role of neuroinflammation in the development of hypertension and sympathoexcitation (1), (2), (3). Interleukin 10 (IL-10) is a major anti-inflammatory cytokine. Its concentration correlates inversely with levels of proinflammatory cytokines that have been implicated in pathogenesis of hypertension (4), (5). Aim: In the present study, we aimed at finding out if concentrations of IL-10 and its receptor in the key cardiovascular centres of the brain differ between spontaneously hypertensive (SHR) rats and normotensive Wistar-Kyoto (WKY) rats. Methods: We carried out the study on adult male SHR (n=6) and WKY (n=6) rats. Systolic blood pressure was noninvasively measured with tail-cuff method. Subsequently, rats were deeply anesthetized with urethane (1.5 g/kg b.w., intraperitoneal) and blood was collected. Immediately after euthanasia, brains were snap-frozen in liquid nitrogen. Brains and serum were stored at -80oC for further analysis. The hypothalamus (HTH), the rostral ventrolateral medulla (RVLM) and the nucleus of the solitary tract (NTS) were isolated from coronal sections obtained with a rat brain matrix. Tissues were homogenized and centrifuged for further analysis by the enzyme-linked immunosorbent assays. Concentration of IL-10 was determined in the supernatants of HTH, RVLM and NTS; IL-10R concentration was determined in the precipitates of the respective areas. Concentrations of norepinephrine (NE), IL-10 and IL-10R were determined in serum. Results: SHR rats had significantly higher systolic blood pressure and serum NE than WKY rats, 190±15 vs 146±19 mm Hg (p<0.001, Student’s t-test), 12.60±1.95 vs 3.77±1.44 (p=0.036, Student’s t-test), respectively. Protein expression of IL-10 in RVLM and NTS of SHR rats was significantly higher than in WKY rats, 3281±532 vs 2086±118 pg/g of tissue (p=0.005, Student’s t-test) and 3430±399 vs 2216±171 pg/g of tissue (p=0.001, Student’s t-test), respectively. Concentration of the cytokine in the HTH and serum did not differ significantly between WKY and SHR rats. IL-10R was significantly lower in NTS of SHR than WKY rats, 39.23±18.59 vs 79.29±22.49 ng/g of tissue (p=0.033, Student’s t-test) and lower in RVLM of SHR than WKY rats, 35.81±23.51 vs 75.29±23.65, however without reaching significant level (p=0.056, Student’s t-test). Concentration of IL-10R was similar in HTH of both SHR and WKY rats. Values are expressed as means ± SD. Conclusions: Our results point to the imbalance between increased expression of IL-10 and decreased expression of its receptor in regions of the brain involved in the regulation of cardiovascular system in SHR in comparison to WKY rats, suggesting involvement of the cytokine in the pathogenesis of hypertension.