[Mechanisms of the adaptation of the cardiovascular system to the action of physical loads on the body]. / Mekhanizmy adaptatsii serdechno-sosudistoi sistemy k vozdeistviiu na organizm fizicheskikh nagruzok.

Diastolic BP rose and cardiac output diminished after 6 months of exercises training because of the increase in peripheral resistance of blood vessels in athletes. In result of the training, skeletal muscles became capable of a profound relaxation leading, in its turn, to development of the ability for marked constriction of skeletal muscles' arterioles. After the exercises, the rigidity of femoral and tibial arteries decreased as the result of involvement of the artery walls' smooth muscle cells into peripheral vasodilatation. The functional condition of the skeletal muscles' arterioles seems to be the main factor affecting circulatory changes both during acute effect of exercise and after a prolonged training.

[Effect of nonachlazine on the cardiac component of baroreceptor reflexes in unanesthetized cats]. / Vliianie nonakhlazina na serdechnyi komponent baroretseptivnogo refleksa u nenarkotizirovannykh koshek.

Nonachlazin in doses of 1 and 6 mg/kg provoked a rise in the arterial pressure of cats by 7--20 mm Hg. Administration of 1 mg nonaclazin into the IV ventricle induced a similar elevation of arterial pressure. Premedication with propranolol (1--3 mg/kg) did not prevent the pressor reaction. In half of the experiments, nonachlazin (6 mg/kg) produced an appearance of Meyer's waves and inhibition of the cardiac component of the barorecptor reflex that is not related to the potentiation of the sympathetic effects on the heart.

[Effect of static work on the baroreceptor reflex in cats]. / Vliianie staticheskoi raboty na baroretseptivnyi refleks u koshek.

10 cats were trained to pull a weight for escaping a noxious stimulation. Arterial pressure and heart rate increased during isometric exercise, while cardiac output did not change. Artificial rising of the blood pressure by noradrenaline infusion or by short-lasting occlusion of thoracic aorta was used to test chronotropic component of the baroreceptor reflex. The baroflex bradycardia was partly inhibited during presentation of conditioned stimulus (tone 1000 Hz) and even more during isometric exercise. Mechanisms of the suppression of baroflex during muscular exercise are discussed.

[Hemodynamic reactions in cats exposed to physical loading]. / Gemodinamicheskie reaktsii u koshek pri fizicheskoi nagruzke.

Cats were trained to pull with a force equal to 50--200% of their body weight. The mean arterial pressure and heart rate increased during the exercise. Pressor response was due to the increase of peripheral vascular resistance, as the cardiac output was constant or even decreased. Blockade of vegetative nervous system led to a 2--3 fold decrease of the pressor response. The conditioned stimulus for "work" had no effects in intact cats, but evoked obvious pressor response in curarized cats. Mechanisms of the vegetative changes during static work are discussed.

[Autonomic reactions arising during skeletal muscle contraction in freely moving cats]. / Vegetativnye reaktsii, voznikaiushchie pri sokrashchenii skeletnykh myshts u koshek v usloviiakh svobodnogo povedeniia.

Cardiovascular responses, evoked by n. gastrocnemius stimulation, were studied in intact cats with implanted electrodes. Non-noxious m. gastrocnemius contraction caused a rise of blood pressure and tachycardia. During curarization painless and threshold painful nerve activation failed to lead to vegetative shifts. The reflex vegetative responses during muscle contraction in intact animals may be used as a model of hemodynamic and respiratory changes in man during muscle exercise.

[Inhibition of the cardiochronotropic component of baroreceptor reflexes following activation of somatic afferents]. / Tormozhenie kardiokhronotropnogo komponenta refleksa s baroretseptorov pri aktivatsii somaticheskikh afferentov.

Stimulation of cutaneous or muscle nerve as well as activation of ventral roots L6--S1 led to inhibition of vagal bradycardia evoked by noradrenaline, in unanesthetized decerebrated cats. Unnociceptive stimulation of m. gastrocnemius in unrestrained cats evoked contraction of the muscle and was followed by depression of the cardiac component of baroreceptive reflex. Propranolol had no effect on this response, while methylatropin abolished it completely.

[Depressor reactions to sural nerve stimulation in intact unanesthetized cats]. / Depressornye reaktsii na razdrazhenie ikronozhnogo nerva u intaktnykh nenarkotizirovannykh koshek

Changes in the arterial pressure, in the heart and respiratory rate evoked by the gastrocnemuis nerve stimulation were studied on conscious cats before and during intravenous injection of noradrenaline. Stimulation of the gastrocnemius nerve increased the arterial pressure, the heart and respiratory rates. The same stimulation of the nerve during hypertension caused by noradrenaline injection led to the fall of arterial pressure and tachycardia. The depressor response failed to change under the effect of the beta-adrenoreceptor block and disappeared after the m-cholinoreceptor block with methylatropine. The depressor response was absent in the unanesthetized decerebrated cats. It is supposed that the depressor response of the arterial pressure depended on the strong cholinergic vasodilatation, reflexively evoked by stimulation of the motor nerve in the intact cats.

[Effect of sydnophen and caffeine on reflex shifts in arterial pressure arising during skeletal muscle contraction]. / Vliianie sidnofena i kofeina na reflektornye sdvigi arterial'nogo davleniia, voznikaiushchie pri sokrashchenii skeletnykh myshts

The influence of sydnophen (5-20 mg/kg) and of caffein (10-40 mg/kg) on the pressor reaction of the arterial pressure, provoked by contraction of skeletal muscles following stimulation of the anterior spinal cord roots (L6, L7, S1) was investigated in 17 tests set up on decerebrated non-narcotized cats. The intraveonus injection of sydnophen was attended by a fall of the arterial pressure and inhibition of the pressor reflex. Caffein reduced the intensity of the pressor reflex to a lesser extent and did not modify the initial level of the arterial pressure.

[The pressor reflex induced by skeletal muscle contraction and its influence on the reflex from the sino-aortic zones]. / Pressornyi refleks, vyzvannyi sokrashcheniem skeletnykh myshts, i ego vliianie na refleks s sino-aortal'nykh baroretseptivnykh zon

The cardiovascular response to 10 sec tetanic muscular contractions was studied in the decerebrated cat. A pressor reflex about 30 mm Hg occurred during hindlimb contractions evoked by ventral roots (L6, L7, S1) stimulation. The pressor reflex was associated with a decrease of blood flow in working and resting muscles and a minimal changes of heart rate and left ventricular contractility. An increase of systemic resistance, as a main cause of pressor reflex is suggested. Static contractions of muscles and stimulation of muscle nerve evoked stronger inhibition of baroreflex than cutaneous nerve stimulation of nociceptive stimuli. Inhibition of the cardiac component of baroreflex during muscular exercise was shown.

[Effect of phenamine and gutimine and gutimine on adaptive changes in arterial pressure occurring during skeletal muscle contraction]. / Vliianie fenamina i gutimina na adaptatsionnye izmeneniia arterial'nogo devleniia, voznikaiushchie pri sokrashchenii skeletnykh myshts

Effects of amphetamine (0,1--11 mg/kg) and gutimin (5--50 mg/kg) on the pressor reflex originating in the exercising muscle were studied on nonanesthetized decerebrate cats. Isometric exercise of the hind limb muscles was elicited by stimulating the spinal ventral roots L6--S1. Amphetamine (0.1 mg/kg) increased the level of arterial pressure and the amplitude of the pressor reflex. Higher doses of amphetamine decreased the pressor reflex to exercises and there was a fall of arterial pressure. Gutimin elevated the arterial pressure and failed to alter the pressor reflex to exercises.