Biomedical subjects

R M Srapionian

Publications and source records attributed to R M Srapionian.

7 recordsLinked to original sources

PubMed1990

[Distribution of neurospecific cardioactive protein-hormone complex in the rat body during experimental myocardial ischemia].

For more than 25 years the chemistry and the function of the protein-hormonal complexes (produced by magnocellular nuclei of human and same animals) have been studied. The methods of radioimmunological analyses (RIA) for the detection of new neuropecific cardioactive protein-hormone "K" (RHK) in rat organism with myocardial ischemia has been developed. Concentration of PHK in various regions of the brain by RIA a four days after the occlusion of the carotid artery has a sharp decrease. Particularly concentration of PHK decreases 100-fold in the cerebral cortex. At the same time the level of PHK content in the blood increased from 13 +/- 0.85 to 630 +/- 3.9 ng/ml. The maximum concentration of PHK shows a sharp rise in the spleen 200-fold of their original level. This distribution pattern implies that PHK may be of importance for peripheral tissues and to the scarring in heart neurosis zone.

Animals↗

PubMed1978

[Specific hypothalamic proteins].

We had previously shown the presence of four protein fractions in hypothalamus of cattle having a coronarodilatatory effect. In this study we have developed methods for the isolation of these proteins and have studied some of their physicochemical properties, amino acid composition, molecular weight, iso-electric point etc. The results obtained have shown that the methods used enable the isolation of quite pure coronaroactive proteins, the content of which in the hypothalamus is equal to 12 mg/kg of fresh tissue. A study of the amino acid composition of these proteins has shown that they are not of the same type. They also differ in molecular weight, in their electrophoretic properties on 7.5% polyacrylamide gel and their iso-electric points. The possibility of a dual function of these proteins as carriers and precursors of corresponding neurohormones is discussed.

Amino Acids↗

PubMed1976

[New findings concerning the coronaroactive proteins of the hypothalamus].

Our previous studies have shown that the two coronarodilatatory hypothalamic proteins isolated by us are not only carriers for neurohormones "K" and "C" but also procursors of coronarodilatory substances. In the present study we have looked at some physico-chemical properties of these proteins through isoelectric focusing and gel electrophoresis as well as the possibility of obtaining coronaroactive fragments by proteolytic enzymes. The results obtained have shown that the isoelectric points of the coronaroactive proteins are between pH 6.2 and 6.4. Polyacrylamide gel-electrophoresis has shown that one of the coronaroactive proteins, the carrier of neurohormone "C", moves towards the anode and is homogenous while carrier of neurohormone "K" is made up of two protein fractions. Under the action of certain enzymes (trypsin and pepsin) two coronaroactive fragments are obtained from the "neutral" protein carrier. Such an effect is not observed following the action of pronase and chymotrypsin. The physico-chemical properties of these fragments require further studies.

Animals↗

PubMed1975

[New findings concerning cardiac proteins binding the coronary dilating substances of the hypothalamus].

We had previously shown that the protein component obtained from heart muscle by 0.1--0.2 saturation with ammonium sulfate exhibits a coronarodilatatory effect. Later on we succeeded in isolating from this protein complex, through dialysis, two coronaoractive low molecular compounds, one of which is apparently a neurohormone. In the present study we isolated, purified and studied the features of this protein complex. The results of gel filtration on Sephadex G-100 confirmed the presence of two different coronaroactive neurohormone binding proteins in heart muscle. The active fractions have been also purified through ion exchange chromatography on diethylaminoethyl cellulose. The purity of these fractions was tested through electrophoresis on 7.5% polyacrylamide gel. In the last stage of purification the active proteins moved towards the anode by one zone.

Animals↗

PubMedDate not supplied

[Coronary-active bovine heart proteins induce relaxation in the rabbit aorta].

Seven cardioactive polypeptides have been identified in the precardiac and auricular regions of the bovine heart. Those polypeptides were studied for their action on the function of isolated preparations of the vessel. It has been found that compounds isolated from the precardiac region induce different (20-55%) relaxation of smooth muscles in a strip of the aorta of rabbit. The possibility of formation of endogenic cardioactive compounds in model experiments imitating processing is studied. The data obtained permit assuming and alternatively explaining existence of multiple forms of the mentioned compounds as a result of partial proteolytic splitting of larger molecules.

Animals↗

PubMedDate not supplied

[Detection and identification of new cardioactive proteins in cattle heart].

Seven cardioactive polypeptides were identified in precardiac and auricular regions of bovine heart. Procedures used for purification of the polypeptides involved extraction of water-soluble proteins, fractionation by ammonium sulfate, gel filtration on Sephadex G-100, chromatography and rechromatography on DEAE cellulose. Some physico-chemical and biological properties were studied; amino acid composition, N-terminal amino acids, molecular mass and the effects on coronary blood vessels. The data obtained suggest that multiple forms of these proteins may exist either as a result of partial hydrolysis of large molecules or due to processing of precursors.

Amino Acids↗

PubMedDate not supplied

[Regional, cellular, subcellular distribution of neurospecific protein-hormonal complexes].

A sensitive radioimmunological assay (RIA) has been developed to detect the tissue specificity and subcellular localization of three specific protein-hormonal complexes (PHC) of the hypothalamus which have a regulatory function in the brain and visceral organs. Using the highly specific rabbit antisera to beef PHC an order of increasing immunoreactivity in different areas of CNS is as follows: hypothalamus, cerebellum, occipital cortex. The PHC-like immunoreactivity (IR) is found in the neurosecretory granules of the hypothalamo-neurohypophyseal system (about 30%) and in the synaptosomal fraction (70%). In the myelin, mitochondrial and nuclear fractions the PHC-like IR is not revealed. IR of PHC is 1000-fold higher in the brain than in visceral organs (heart, skeletal muscles, adrenals, pancreas and blood serum). A possible role of the PHC as markers of the neuroendocrine cells is discussed.

Animals↗