[Protective effect of endothelin-1 in goldblatt "one-kidney, one-clip" hypertension].

The aim of the study was to evaluate the effect of chronic inhibition of endothelin-1 (ET-1) synthesis on renovascular hypertension development. Male Wistar rats were subjected to an operation, according to the "1 kidney, 1 clip" method and were given an endothelin-converting enzyme inhibitor PP36 per os with drinking water for 4 weeks. Serum urea rose by 21% in hypertensive rats and by 44% in PP36 treated hypertensive rats.

[Influence of corticotropin-releasing factor fragment CRF4-6 on metabolism in rats].

Influence of corticotropin-releasing factor fragment CRF4-6 on metabolism in the rat was investigated in this study. Tripeptide (10 mkg/rat) after intracerebroventricular infusion to anesthetized animals increased metabolic rate, not affecting the respiratory ratio, induced hyperglycemia and hyperthermia. Synchronously with that heart rate and arterial pressure did also increase.

[Changes in the diaphragm muscle and its feed artery after chronic respiratory airway obstruction in rats].

A chronic respiratory load was produced in Wistar rats by tracheal binding to produce a twofold increase of pleural pressure oscillation amplitude during respiration. Eight weeks after the surgery, a higher proportion of type-I muscle fibers (MFI) in the costal diaphragm along with a greater MFI cross-section area and a higher succinate dehydrogenase activity in MFII in the crural diaphragm were observed. During recording the mechanical activity of ring preparations of diaphragm arteries under isometric conditions, an increase in endothelium-dependent relaxation was found, whereas endothelium-independent relaxation and arterial reactivity to noradrenaline did not change.

Effect of aerobic training on innervation density and neurogenic responses of skin afferent blood vessels.

We studied the effect of 8-week aerobic training (treadmill running) on neurogenic responses and density of sympathetic innervation of subcutaneous artery in rats. In trained rats, the artery response to stimulation of intramural sympathetic nerve decreased, but the sensitivity of vascular smooth muscles to norepinephrine was not changed. The density of adrenergic nerve fibers in the arterial wall after training was also lower than in the control group.

[Comparative analysis of vasomotor responses and sympathetic innervation of feed arteries from locomotor and respiratory muscles in a rat].

The characteristics of feeding arteries of diaphragm and medial gastrocnemius (with a diameter of 200-250 micron) were studied. The registration of the mechanical activity of ring preparations under isometric conditions revealed that diaphragm arteries, like arteries of other muscles with a high content of slow muscle fibers, are highly sensitive to adrenoceptor agonists and acetylcholine. The differences in endothelium-dependent relaxation between diaphragm and gastrocnemius arteries are preserved in the presence of L-NAME and diclofenac.