Background Endogenous hydrogen sulfide is a new neuromodulator which takes part in the regulation of central nervous system physiology and diseases. Whether endogenous hydrogen sulfide in the central nervous system regulates cardiovascular activity is not known. In the present study, we observed the hemodynamic changes of hydrogen sulfide or its precursor by intracerebroventricular injection, and investigate the possible roles of endogenous digitalis like factors and sympathetic activity in the regulation. Methods Ninety-four Sprague-Dawley rats underwent a right cerebroventricular puncture, then the hydrogen sulfide saturation buffer or its precursor injected by intrcerebroventricular catheter. A heperin-filled catheter was inserted into the right femoral artery or into the left ventricle, and changes of blood pressure or cardiac function recorded by a Powerlab/4S instrument. Phentolamine or metoprolol were pre-injected to observe the possible role in autonomic nerve activity. After rats were sacrificed, plasma was collected and endogenous digitalis-like factors were measured with a commercial radioimmunoassay kit. The aortic, cardiac sarcolemmal vesicles were isolated and the activity of Na＋-K＋-ATPase was measured as ouabain-sensitive ATP hydrolysis under maximal velocity conditions by measuring the release of inorganic phosphate from ATP. Unpaired Student＇s ttest for two groups or analysis of variances （ANOVA） for multiple groups were used to compare the differences of the changes. Results Intracerebroventricular injection of hydrogen sulfide induced a transient hypotension, then dramatic hypertenive effects in a dose-dependent manner. Bolus injection of L-cysteine or beta-mercaptopyruvate also increased mean arterial pressure （P 〈0.01）, whereas hydroxylamine-a cystathionine beta synthase inhibitor decreased the arterial pressure （P 〈0.01）. Hydrogen sulfide and L-cysteine increased mean arterial pressure, left ventricular develop pressure and left-ventricle maximal rate of systolic and di
REN Yong-shengWU Sheng-yingWANG Xing-junYU FangZHAO JingTANG Chao-shuOUYANG Jing-pingGENG Bin
