To determine the role of proteasome proteolysis in the pathogenesis of hypertension, we have studied the proteolytic activity of the proteasome in the aorta and heart tissues of rats with spontaneous hypertension (line SHR), and used quercetin, the drug that can inhibit the activity of this multicatalytic complex. In the aorta of SHR, the activities of the proteasome were not significantly different from that observed in Wistar rats. At the same time, in the heart tissues the trypsin-like (at 40 %, P > 0.05), and chymotrypsin-like (by 1,7 times, P < 0.03) activities were significantly less in SHR. significant morphological changes (fibrosis of the left ventricle was 4.7 %, aorta intima width was increased and heart weight index was higher by 21,6 % (3,7 ± 0,6 mg/g) compared with Wistar rats (2,9 ± 0,4 mg/g, P < 0.004) were observed in these animals functional disorders (reduced stroke volume by 3 times (P < 0.0001), ejection fraction by 2.5 times (P < 0.0001), increased end diastolic pressure by 6.5 times (P < 0.005), end systolic pressure by 15 % (P < 0.004)) were revealed. Pharmacological drug “Qvercetin” effectively inhibited trypsin-like and chymotrypsin-like proteasome activities Вплив кверцетину на протеасомну активність в аорті та серці щурів ISSN 0201-8489 Фізіол. журн., 2014, Т. 60, № 3 9 in the aorta (2.7-fold (P < 0.005) and 2-fold (Р<0,003), correspondingly) and trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing-like activities (2.4 -fold, P > 0.05 and 9.3- fold, P < 0.02, correspondingly) activities in the heart, leading to a significant improvement of morphological and functional parameters of the heart. Whereas the drug “Qvercetin” that is widely used in clinical practice (especially in therapy of acute myocardial infarction) it could be recommended for the use in prevention of cardiac remodeling with high level of blood pressure.