[The resistive and capacity functions of the subcutaneous vein under blockade of calcium channels and endothelial factors].

In cats, the calcium antagonist Verapamil depressed vein constrictor responses to noradrenaline and angiotensine II both under conditions of wholesome endothelium and physical-chemical and chemical de-endothelisation. Following the de-endothelisation the vein responses recovered. The data obtained suggest that this recovery seems to be due to opening of new calcium channels that are independent of the Verapamil effect.

[Effect of taurine on the microvessel exchange function and adrenergic response of veins and arteries in the cat skeletal muscle]. / Deistvie taurina na obmennuiu funktsiiu mikrososudov i adrenergicheskuiu reaktivnost' arterii i ven skeletnoi myshtsy u koshek.

In cats anesthetized with Uretan and perfused with a constant blood volume, Taurine induced responses of neither arterial nor venous vessels of the skeletal muscle but increased the capillary filtration coefficient without any significant change of the capillary pressure in the skeletal muscle's microvessels. Taurine also increased both the constrictor and the dilatory responses of the arterial and venous vessels. The mechanism of the Taurine effects upon the smooth muscle elements of arteries and veins as well as upon proper mechanisms of capillary pressure control and capillary filtration coefficient, seems to be calcium-dependent.

[Capacity and exchange functions of the kidney blood vessels at various leveles of venous outflow]. / Emkostnaia i obmennaia funktsii krovenosnykh sosudov pri raznykh urovniakh davleniia venoznogo ottoka.

In perfusion of the cat hemodynamically isolated kidney with a constant blood flow volume, responses of venous vessels to noradrenaline did not depend on the venous outflow pressure level and only involved a diminishing of the blood filling which distinguishes kidneys from other organs. The renal veins' capacity decreased in response to noradrenaline practically completely disappears in high values of the venous outflow pressure. The renal capillary filtration coefficient was shown to equal 0.21 +/- 0.11, whereas the effect of changes in renal vein's pressure on implementation of the microvessels' exchange function in determined by the shifts of capillary hydrostatic pressure.

[Dependence of constrictor and dilator humoral responses of arteries and veins in the small intestine on calcium ions entering vascular myocytes]. / Zavisimost' konstriktornykh i dilatatornykh gumoral'nykh reaktsii arterii i ven tonkoi kishki ot vkhoda v sosudistye miotsity ionov kal'tsiia.

Verapamyl administered to the intestine circulation in the dose evoking no shifts in the arterial and venous resistance or in the vascular capacity, decreased 2- or 3-fold both the constrictor and dilatory responses of the arterial vessels. Against the background of Verapamyl, noradrenaline and isoproterenol did not practically change either capacity or resistance in the veins. Responses of veins to angiotensin II increased 10-fold and more, whereas they were absent after administration of atropine into the intestine circulation. Constrictor and dilatory responses of veins need to a greater extent than the arteries penetration of external calcium ions to their myocytes.

[The effect of changes in the blood flow and the level of arterial and venous pressures on the filtration-absorptive processes in the small intestine]. / Vliianie na fil'tratsionno-absorbtsionnye protsessy v tonkom kishechnike izmenenii krovotoka, urovnia ego arterial'nogo i venoznogo davleniia.

Under conditions of perfusion of the small intestine's vessels with constant volume of the auto-blood, stationary shifts of the arterial perfusion pressure by +/- 50 mm Hg and/or blood flow by +/- 50% of the initial level practically did not affect the size of the exchange surface of the organ's microvessel bed (the capillary filtration coefficient) or the average capillary pressure in artificially stabilised pressure of venous outflow at the level of 6 mm Hg. However, under conditions of normo-, hypo- and hypertone of the small vessels' smooth muscles, the shifts of the venous outflow pressure (from 0 to 24 mm Hg) increased the exchange surface of the microvessels and the average capillary pressure. The mechanisms of the shifts in microhemodynamics and transcapillary exchange of fluid are discussed.

[The effect of long-term venous hypertension on the macro- and microhemodynamics in the skeletal muscle]. / Vliianie dlitel'noi venoznoi gipertenzii na makro- i mikrogemodinamiku v skeletnoi myshtse.

Preliminary artificial venous hypertension of hindlimbs for 4-6 weeks was followed by comparison of resistive, capacitance and metabolic functions of the m. gastrocnemius' vessels performed in experimental and control cats with different levels of initial pressure of venous outflow. An increase of precapillary resistance, of the capillary filtration coefficient, a decrease of distensibility of the muscle venous bed, and constancy of postcapillary resistance and mean capillary pressure, were found in experimental animals. Mechanogenic responses of the muscle venous vessels to a rapid increase of the pressure in them were augmented in animals with chronic venous hypertension. The mechanisms of the effect of prolonged venous hypertension on functions of skeletal muscle's vessels, are discussed.

[Functional relationship of venous to metabolic vessels of muscles in experimental venous insufficiency]. / Funktsional'noe sootnoshenie venoznykh i obmennykh sosudov myshtsy pri éksperimental'noi venoznoi nedostatochnosti.

Modelled venous insufficiency of the hind limbs of cats (ligation of the posterior vena cava for 4-6 weeks) led to structural reorganization of the venous walls of the gastrocnemius muscle, which was manifested by a sharp increase of stretchability of the venous bed of the muscle if the activity of the smooth muscles was removed by papaverine, and by significant loss of the sensitivity of the smooth muscles of the intramuscular veins to noradrenaline as regards function. The range of adrenergic changes of postcapillary resistance and capillary pressure was reduced sharply in animals with venous insufficiency. This may be among the causes of disorders of metabolic processes in the skeletal muscles in venous insufficiency.

[The organic macro- and microhemodynamics and the systemic circulation under the combined action of hypoxia and hypothermia]. / Organnaia makro- i mikrogemodinamika i sistemnoe krovoobrashchenie pri sochetannom deistvii gipoksii i gipotermii.

In regimen of the constant blood flow perfusion of shank and small intestine of cat combined effect of hypoxia (10% O2 in N2) and hypothermia (about 30 degrees C) involved a decrease in precapillary resistance, an increase in capillary filtration coefficient in both vascular regions, an increase in postcapillary resistance and in mean capillary pressure in the intestine, and their decrease in the shank. In hypothermia, the hypoxic stimulus induced insignificant shifts in all the parameters under study in both organs. Dependence of hypoxic changes of macro- and microhemodynamics on the activity of adrenergic receptors in the cooled organism was studied on decentralized shank of cat. After cooling of cat and blockade of alpha-adrenoreceptors hypoxic hypoxia caused much greater reduction of precapillary resistance of shank, more striking (by 3 times) increase of capillary filtration coefficient and the increase of capillary pressure and postcapillary resistance in contrast with their decrease to hypoxia under hypothermia before alpha-blockade. Beta-adrenoreceptor blockade had no influence on the changes of the resistance and exchange function of skeletal muscle (shank) blood vessels evoked by hypoxia under cooling. Systemic arterial pressure are diminished during hypoxia under the normothermic conditions of animals. Such kind shifts caused especially by the decreasing of the total peripheral resistance; cardiac output are small raised in this situation. But combined influence of hypoxia and hypothermia evoked the pressor shifts of the systemic arterial pressure because of less decrease of total peripheral resistance and more remarkable rise of cardiac output. Hypoxic stimulus caused both in normothermia and hypothermia conditions caused the rising of venous return.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effectiveness of the joint action of vasodilator humoral stimuli on the arterial and venous vessels of the skeletal muscle]. / Effektivnost' sochetannogo deistviia vazodilatornykh gumoral'nykh stimulov na arterial'nye i venoznye sosudy skeletnoi myshtsy.

Two pairs of stimuli: isoproterenol and histamine, and isoproterenol and papaverine, did not enhance the effect of their separate components on either arterial or venous vessels, the dilatory responses not exceeding the vascular responses to separate agents. However, if the vascular responses to an isolated component of the pairs differed, then the effect of a pair of stimuli was equal to a greater response from the responses to an isolated component. Venous vessels differed from arterial ones in that their response to a combined action of above substances was sharply reduced as compared to responses to isoproterenol.