Vasoconstriction reactions in tail artery in the rats with regional arterial hypotension

Reactivity of the tail artery to norepinephrine was studied in rats with regional arterial hypotension. Constant-flow perfusion of the artery elicited less pronounced constriction in hypotensive rats in comparison with the controls, while the constant-pressure perfusion evoked stronger vasoconstriction. This is explained by possible involvement of myogenic component in the contractile response. When myogenic reaction was inhibited by enhanced potassium concentration in the perfusion solution, vasoconstriction in hypotensive rats was less pronounced under both perfusion modes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 1, pp. 11–13, January, 1999     

Observance of the optimality principle in the microcirculatory bed of rat brain

An intravital microscopic study of pial microvasculature in the rat cerebral cortex showed that, both in the resting state and when the vessels are dilated as a result of ischemia, the principle of minimal energy expenditure is one of the factors regulating the ratio of arteriolar diameters in arteriolar ramifications. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, No. 8, pp. 134–135, August, 1994     

Reactivity of the conjunctival microcirculatory bed in students from various regions of the world as an indicator of adaptation of the organism

Microcirculatory vessels of the eyeball conjunctiva were examined during exercise in students from Asia, Africa, and Latin America. The reactivity of microvessels was found to be increased at the early stages of adaptation, which indicates a high-level compensatory potential of the organism. An appreciable reduction of microvessel reactivity after 1 to 2 years of university studies indicates a decrease of the compensatory potential in this period of adaptation. After 4–5 years of studies the reactivity of the microvessels is virtually the same in foreign and Russian students, this indicating the formation of a stable phase of adaptation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 423–426, April, 1995 Presented by N. A. Agadzhanyan, Member of the Russian Academy of Medical Sciences     

Changes in the mesenteric microcirculation of rats with acute hypoxic hypoxia

Hypoxia was induced in rats by administration of a gas mixture corresponding to the composition of the atmosphere at an altitude of 6000 m above sea level. Mesenteric arteries and veins measuring from 9 to 43 in diameter were studied. Their diameter and the pressure and velocity of the blood flow in them were measured. The arterial microvessels were dilated in hypoxia. Their diameter was increased by the greatest amount (by 3–5 ) during the first 3–5 min of administration of the gas mixture. The blood pressure and velocity of blood flow in these vessels were reduced throughout the experiment.Department of Normal Physiology, Abu Ali ibn-Sina Tadjik Medical Institute, Dushanbe. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 277–279, March, 1976.     

The state of the microcirculatory bed,microhemodynamics, and oxygen supply of the liver under conditions of disrupted parasympathetic innervation

Vagotomy is shown to result in disturbances of the microcirculation (a reduced rate of blood flow and distortion of its kinetics), the morphological basis of which consists of certain transformations of the microvascular network organization and ultrastructural changes in the cells lining the sinusoidal capillaries. The most pronounced disorders in microhemodynamics and blood supply of the liver are found 5–14 days after vagotomy. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 328–330, September, 1994 Presented by V. V. Kupriyanov, Member of the Russian Academy of Medical Sciences     

Role of microcirculatory disorders in the morphogenesis of fissured ulcers in children with terminal ileitis

Structure and ultrastructure of ileal biopsy specimens were studied in 6 children with Crohn's disease in order to investigate the morphogenesis of fissures. Microcirculatory disorders lead to the formation of microinfarctions which are shaped as long fissures due to tissue vascular architectonics and peristaltic movements of the intestine. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 7, pp. 76–77, July, 1999     

Effects of ischemia on the development of a deafferentation pain syndrome and on microcirculatory disturbances in rats

In a group of rats with transected sciatic nerve, ischemia of the operated limb produced by femoral artery ligation was found to result in an accelerated onset and increased severity of autotomy as compared to a similar group of rats without ischemia. Biomicroscopic examination of the mesenteric microcirculation showed that the ischemia also intensified disturbances of the terminal blood flow, made the venules more permeable, and increased the percentage of degranulated mast cells. The possible mechanisms by which ischemia promotes the development of chronic pain syndromes are discussed. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 3, pp. 235–237, March, 1994 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Thermal adaptation activates HSP70 synthesis, inhibits overproduction of nitric oxide, and protects the body from acute hypotension during heat shock

The role of HSP70 and nitric oxide in antihypotensive effects of thermal adaptation was studied. Western blot analysis and electron paramagnetic resonance were used to determine the contents of HSP70 and nitric oxide. Protective effect of adaptation was evaluated by the limitation of blood pressure drop after heat shock. The formation of protective effects, accumulation of HSP70, and development of the ability to decrease nitric oxide overproduction had similar dynamic patterns and appeared at the same period. Quercetin, an inhibitor of HSP70 synthesis, prevented the development of protective effects. The data suggest that HSP70 accumulated during adaptation prevents heat shock-induced hypotension by restricting NO over-production and interfering with its cytotoxic effects. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 11, pp. 507–510, November, 1999     

The sympathetic nervous system is not involved in the development of atropine tachycardia

There is a consensus that the vagus nerve produces a permanent (tonic) inhibitory effect on heart activity. However, some recent experimental findings attest that the vagus tone is not pronounced and suggest that excittion of the sympathico-adrenal system is the cause of atropine tachycardia. We found in acute and chronic experiments that the blockage of the sympathetic nervous system does not abolish atropine- and methacin-induced tachycardia. At rest heart activity is regulated by the vagus as well as by humoral agents circulating in the blood. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 234–237, September, 1994 Presented by A. A. Ado, Member of the Russian Academy of Medical Sciences     

Myogenic tone and neurogenic vasoconstriction in microcirculatory bed of rat cerebral cortex

The reaction of rat parietal cortical vessels to stimulation of the sympathetic ganglion was studied by intravital microscopy. stimulation induced constriction of cerebral arterioles. Clamping of one or both carotid arteries led to myogenic vasodilatation in the majority of cases. Constrictive response of brain arterioles to ganglion stimulation under conditions carotid occlusion did not differ from that under conditions of baseline cerebral blood supply.     

The microcirculatory bed of hamster cheek pouches after occlusion of the common carotid arteries

The responses of hamster cheek pouch microvessels after occlusion of the common carotid artery on the ipsilateral side are compared. It is found that under conditions of limited inflow the microvessels preserve the inflow on the left side and the outflow on the right side, with venular constriction predominating in the left cheek and arteriolar in the right. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 144–147, February, 1996 Presented by V. V. Kupriyanov, Member of the Russian Academy of Medical Sciences)     

Status of adrenergic nerve supply to the ventricular myocardia in experimentally produced massive pulmonary embolism

The production of massive pulmonary embolism in dogs initially results in elevated norepinephrine levels in the stellate ganglion and ventricular myocardia. Six hours after its onset, destructive changes in the stellate ganglion nerve cells are more pronounced than at 1 h and their functional activity is decreased, as are norepinephrine levels in the adrenergic neurons and their terminals. A characteristic feature of compensated massive pulmonary embolism is the presence of many neurons showing pronounced hyperchromatosis and pyknomorphic shrinkage. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N^no 10, pp. 368–373, October, 1994 Presented by V. S. Savel'ev. Member of the Russian Academy of Medical Sciences     

Neurohormonal changes in acute pulmonary embolism (an experimental and clinical study)

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 7, pp. 29–31, July, 1993.     

Pathological integrations in the central nervous system

Damage to the nervous system is a causal and conditioning event leading to the development of pathological processes mediated via such endogenous mechanisms as the formation of integrative complexes from damaged and secondary changed nervous structures that are pathological by their nature, mechanisms, and effects. At the level of neural relationships such pathological integrative complex (PIC) is formed by an aggregate of hyperactive neurons (generator of pathologically enhanced excitation, GPEE) producing uncontrollable ongoing flow of nerve impulses. At the systemic level, PIC is a new pathodynamic system composed of various subdivisions of the CNS, which acts as a pathological system. The subdivision of the CNS containing GPEE assumes the role of a pathological determinant due to its enhanced activity. This pathological determinant induces the formation of a pathological system and controls its activity at the early period of its genesis. Every neuropathological syndrome is a clinical or behavioral manifestation of pathological system activity. Pathological determinant and pathological system are general biological categories that fall outside the scope of nervous disorders. They can arise in various systems at the micro- and macroscopic levels and induce systemic pathology. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 3, pp. 244–247, March, 1999 Original article submitted October 5, 1998     

Posthypoxic changes in the cerebral cortex of dogs in the late recovery period after hypovolemic hypotension for 4 hours

On the 14th–21st day of the recovery period after hypovolemic hypotension lasting 4 h the total RNA level in the tissue of the gray matter of the brain fell by 20.9% and the DNA level by 13%. In the postmitochondrial supernatant the concentration of prealbumins fell by 26.5%, of -globulins by 19.2%, and of -globulins by 59.8%; the concentration of albumins and -globulins increased by 12.6 and 50% respectively. Activity of acid cathepsins rose by 50% and of acid phosphatase by 44%. Activity of total lactate dehydrogenase (LD) and glutamate dehydrogenase did not differ significantly from the control values. However, the LD isozyme spectrum showed a decrease in LD₃₊₄₊₅ from 31.9 to 14.2%. Analysis of densitograms of electrophoresis in polyacrylamide gel showed changes in the physiocochemical properties of the protein molecules similar to denaturation in nature. The number of Purkinje cells in the cerebellar cortex was 41.3% below the control level.Laboratory of Experimental Physiology of Resuscitation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 933–936, August, 1976.