Introduction: Accumulating evidence suggests that hydrogen sulfide (H2S) is an important biological mediator involved in various physiological processes including the regulation of the circulatory system (1,2,3). Furthermore, it has been postulated that disturbances in H2S homeostasis may result in hypertension (1). This may be due to the involvement of H2S signalling in both peripheral and the brain mechanisms controlling arterial blood pressure (1,2,3). In this study we checked the hemodynamic response to intracerebrovetricular (ICV) infusion of NaHS, a H2S donor in normotensive and hypertensive rats.Methods: We did experiments on 12-14 weeks old, male, normotensive Wistar Kyoto rats (WKY, n=6), spontaneously hypertensive rats (SHR, n=6), angiotensin II – induced hypertensive rats (WKY-Ang II, n=6) and high fructose diet-induced hypertensive rats (WKY-HFD, n=6). The experiments were made according to the Directive 2010/63/EU and approved by the Ethical Committee of the Medical University of Warsaw. In WKY-Ang II rats hypertension was induced by osmotic minipump driven subcutaneous infusion of ANGII (450ng/kg/min) while in WKY-HFD rats by drinking water containing 10% fructose for 8 weeks. The animals were implanted with a stainless steel cannula into the lateral cerebral ventricle and one week later with a catheter into the abdominal aorta. All surgicals procedures were performed under ketamine (100mg/kg i.p.) and xylazine (10mg/kg i.p.) anesthesia. Mean arterial blood pressure (MABP) and heart rate (HR) were continuously recorded at baseline and during ICV infusions of either NaHS at the rate of 300 nmol/h or vehicle (Krebs-Henseleit buffer) in rats freely moving in their home cages, three days after the last surgery.Results: ICV infusions of vehicle did not affect MABP and HR. ICV infusion of NaHS in WKY rats produced an increase in MABP and HR. In contrast, SHR rats as well as WKY-Ang II and WKY-HFD rats showed significant decrease in MABP and HR during ICV infusion of H2S donor. Autonomic ganglia blockade with hexamethonium (30mg/kg, i.v.) blunted response to NaHS in all the experimental groups. Conclusion: The results provide further evidence that H2S is involved in the neurogenic control of blood pressure. Furthermore, this study shows that hypertensive rats have altered responsiveness to H2S, which may suggest that disturbances in H2S signaling in the brain may be associated with hypertension.