The post-mortem study included 8 healthy men, aged 18-44 years, and 27 men with the life-time diagnosis of hypertension, stage I-III. Using immunocytochemical method, we studied topography, quantitative distribution and enzyme activity in H2S-positive neurons of some nuclei of the medulla oblongata and pons that are part of the cardiovascular center. Changes in cystathionine-beta-synthase activity and in the number of immunopositive cells were found in arterial hypertension. The intensity of these parameters was correlated with the severity of disease. It has been proposed that changes in morphometric parameters of H2S-positive neurons inside the nuclei reflect the character of between-nuclei interactions as well as the organization of the cardiovascular center in whole.