We studied the effects of long-term administration of molsidomine and pentaerythrityl tetranitrate (PETN) on the cardiovascular system of spontaneously hypertensive rats (SHR). One control and three experimental groups of 10-week-old animals were used: 1) control Wistar rats, 2) SHR, 3) SHR treated with molsidomine in tap water (100 mg/kg/day, by gavage), and 4) SHR treated with PETN in tap water (200 mg/kg/day, by gavage). After six weeks, the content of cGMP in platelets and NO synthase (NOS) activity in aortas were evaluated in the experimental groups. For morphological evaluation the rats were perfused at 120 mm Hg with a glutaraldehyde fixative and the arteries were processed for electron microscopy. Blood pressure and heart weight/body weight ratio (HW/BW) were increased in all experimental groups with respect to the controls. HW/BW was lower in the molsidomine group in comparison to both SHR and PETN-treated group. The platelet content of cGMP was increased and the activity of NOS in the aortas was decreased in the molsidomine and PETN-treated groups. Wall thickness and cross-sectional area of thoracic aorta, carotid artery and coronary artery were increased similarly in all experimental groups compared to the controls, but there were no differences among the experimental groups. We summarize that long-term administration of exogenous NO donors did not improve pathological changes of the cardiovascular system in SHR., F. Kristek, V. Fáberová, I. Varga., and Obsahuje bibliografii
Coronary and carotid artery structure was studied in rats in order to analyze the processes in the cardiovascular system in NO-deficient hypertension model. Long-term inhibition of NO synthase was induced by L-nitro arginine methyl ester (L-NAME, 50 mg/kg/day p.o.) for a period of 8 weeks. An increase in blood pressure and heart/body weight ratio confirmed the reliability of the model. The wall thickness as well as the calculated wall area of the coronary artery increased by 70 % and 50 %, respectively, in comparison to control vessels. The wall thickness and the calculated wall area of the carotid artery increased by 73 % and 70 %, respectively. Further analysis indicated that both the tunica intima and tunica media in the coronary and the carotid artery increased quantitatively in a similar manner. Remarkable differences were found in the contribution of cellular and noncellular components in the tunica media of the coronary and carotid arteries of experimental animals. The calculated extracellular area increased by 116 % in comparison to the control coronary artery and by 97 % in comparison to the control carotid artery. The increase in extracellular matrix of the tunica media of coronary and carotid arteries seems to be basic cause of the remodelling of the vessels studied.