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Biomedical subjects

I M Rodionov

Publications and source records attributed to I M Rodionov.

At least 73 records · Page 4Linked to original sources
PubMed1980

[Cholinergic sympathetic influences on blood flow and cyclic nucleotide concentration in skeletal muscles].

The content of 3.5 cGMP increased twofold and the content of 3.5 cAMP remained unchanged in the cat skeletal muscle during vasodilatation evoked by hypothlalamic stimulation. Cholinergic vasodilatation increased also phosphorylase activity by 90%. These effects were blocked by atropine. Possible existence of an interrelationship among the vasodilator effect, phosphorylase activity and increase in cGMP, is discussed.

Animals↗
PubMed1978

Cholinergic and adrenergic influences upon cat skeletal muscle performance induced by stimulation of the anterior hypothalamus.

The influence exerted by stimulation of the anterior hypothalamus (zone of cholinergic vasodilatation) on the performance of triceps surae during tetanic contraction has been investigated. Hypothalamic stimulation, if combined with indirect muscle stimulation, improves muscle performance, i.e. slows down the rate of decrease of contraction. The effect is abolished by atropine (0.5 mg/kg) and insensitive to propanolol (0.1 mg/kg). The cholinergic influence is only effective if hypothalamic stimulation coincides with the beginning of motor nerve stimulation. In some of our experiments stimulation of the same central structures elicited another influence on muscle performance, associated with the release of adrenaline into the blood. In this case, contrary to the cholinergic influence, the force of contraction increases only when hypothalamic stimulation does not start earlier than 100 s after the initiation of contraction (phase of slow decline of tension). The effect is insensitive to atropine (0.1 mg/kg) and abolished by propanolol (0.1 mg/kg).

Animals↗
PubMed1978

On the mechanism of an increase of muscle performance and of vasodilation during emotional stress in man.

The mechanism of the increase of muscle performance and of vasodilation during emotional stress was studied. The "emotional" increment of voluntary performance does not depend on the level of blood supply to the working muscles, and the effect is maintained under conditions of cessation of arterial inflow. Augmentation of muscle performance is also observed during emotional stress when isometric contraction is evoked by electrical tetanic stimulation of the nerve, when the number of muscle fibres participating in the evoked response does not increase during emotional stress. The "emotional" vasodilation is greatly reduced in patients suffering from McArdle's syndrome, in whom the normal course of glycolysis in muscles is disrupted. It is suggested that acetylcholine liberated from sympathetic fibres causes the activation of glycolysis in muscles, which in its turn induces vasodilation in resting skeletal muscles and increase of muscle performance during emotional stress.

Adolescent↗
PubMed1977

[Study of the destruction of the sympathetic ganglia by the administration of guanethidine to newborn rats and mice].

Following the injection of guanethidine (25 mg/kg) to rats from the first day of life during 2 weeks, over 70% of sympathic neurons in the stellate ganglion die. If the injections are carried out during 4 weeks, over 99% of neurons die. The injection of guanethidine to mice during 5 weeks did not result in the destruction of nerve elements in the ganglion, as compared with the control.

Animals↗
PubMed1976

Activation of anaerobic metabolism in cat skeletal muscle during cholinergic sympathetic vasodilatation.

Phosphorylase activity was found to increase 2-fold as compared with the control value (79% and 39% respectively) within the first 2-3 s of the vasomotor effect elicited in the skeletal muscle by sympathetic stimulation. Phosphorylase activity was still high during the period of maximum blood flow, although to a lesser extent (54% and 45%). During the phase of restoration of the initial rate of blood flow the values of phosphorylase activity were the same in the experimental and the control sample. The AMP content did not increase with the initiation of the vasomotor effect, and this fact suggests that the increase in phosphorylase activity is due to an increase in phosphorylase "a" rather than to the activation of phosphorylase "b" by AMP. Atropine blocks both the dilator effect and phosphorylase activation elicited by sympathetic stimulation. Acetylcholine, injected intraarterially or added to a muscle homogenate, increases phosphorylase activity. It is concluded that acetylcholine, released by sympathetic nerve endings, performs a second mediator function, that of activating anaerobic metabolism in the skeletal muscle. The two mediator functions of acetylcholine seem to be spatially delimited.

Acetylcholine↗
PubMed1976

[The growth of axons in the periphery after a decrease in the quantity of nerve cells in sympathetic ganglia].

The amount of cells in stellate ganglia of rat was decreased by chemical sympathectomy to 30% of the normal amount. At the age of two months sympathectomized rats have no pressor reflexes to asphyxia and femoral nerve stimulation. These responses are restored at the age of four months. The electron-microscopic and fluorescence-microscopic data show that the growth of axons in the remaining adrenergic neurons of sympathectomized animals takes place at the age between two and four months.

Age Factors↗
PubMed1976

[Nerve and glial cells of the sympathetic ganglia of mice of different ages. I. Interferometric and electron microscopic study of the perikarya of nerve cells of normally developing animals].

The perikarya of sympathetic nerve cells from stellate ganglia of 1.3 and 8 month old mice were studied by interference and electron microscopy. Both the number of nerve cells and the dry weight of their perikarya are the same in animals of different ages. According to the ultrastructure, all the sympathetic neurons of adult mice belong to one of the two main groups. The "dark" cells are characterized by a higher electron opacity of nucleo and cytoplasm, the convoluted nuclear envelope and endoplasmic reticulum being randomly distributed throughout the cytoplasm. In the "light" cells from ganglia of I and 3 month old mice, the granular endoplasmic reticulum forms a kind of a belt around the nucleus and is situated in the middle area of the cytoplasm. The majority of nerve cells from the ganglia of 8 month old mice, in addition to the increase in pigment granule contents, are characterized by a lower frequency of the rough endoplasmic reticulum without changes in the number of polysomes not attached to membranes.

Age Factors↗
PubMed1976

[Sympathetic ganglia nerve and glial cells in mice of different ages. II. Interferometric and electron microscopic study of the perikarya of neurocytes from a population with a sharply decreased number of cells].

The number of nerve cells in stellate ganglia of mice injected antiserum against the nerve growth factor during the first five days after birth made -- 22%, 19 and 15.5% in 1, 3 and 8 month old animals compared to the control values. The neurons that developed in ganglia with reduced cell numbers are characterized by a higher dry weight of their nuclei and cytoplasm. The ultrastructure of perikaria of such cells has some pecularities different in mice of different age, and are possibly brought about by compensatory changes in the ganglia.

Age Factors↗
PubMed1976

[Sympathetic ganglia nerve and glial cells in mice of different ages. III. Satellite perikaryon cells under normal conditons and following a sharp reduction in the number of ganglionic neurocytes].

Changes induced in perikarial satellite cells by a prolonged increase of the mass and volume of perikaria are studied. The work was fulfilled on the gg. stellatae of adult female mice injected antiserum against nerve growth factor soon after birth (this treatment resulted in an up to 80% decrease of nerve cell bodies per ganglion, accompanied with a significant increase in their volumes). The nerve cell body hypertrophy was followed by hypertrophy and hyperplasy of satellite cells. In addition some prominent changes in the fine structure of satellite cells under experimental conditions were found.

Animals↗
PubMed1975

[Age changes in rat vasomotor reflexes and sympathetic neuron ultrastructure following chemical sympathectomy].

Prolonged administration of guanethidine (20 mg/kg) to newborn rats caused a marked reduction in the number of cells in stellate ganglia. The administration of guanethidine for 14 days decreased the amount of cells to 30% of the normal (partial sympathectomy), and for 28 days--to 0.5% (complete sympathectomy). At the age of two months the blood pressure pressor reflexes to asphyxia and femoral nerve stimulation were absent in both groups of the sympathectomized animals. These responses, however, were restored in the partially sympathectomized animals at the age of four months. No restoration took place in the completely sympathectomized animals. The electron microscopic studies of neurons in the partially sympathectomized animals showed the presence of a great number of neurofibrils. According to literature data this fact was typical of cells in which an active growth of axon fibers took place.

Aging↗