[PHOSPHOLIPIDS, FATTY ACIDS AND HEMOGLOBIN OF ERYTHROCYTES IN RAT BLOOD UNDER STRESS CONDITIONS (SWIMMING AT A LOW TEMPERATURE)].

The phospholipid and fatty acid content of erythrocytes in rat blood was studied after exposure to stress - swimming up to drowning. This stress was found to increase the content of phospholipids cha- racteristic for the membrane outer layer (phosphatidilcholine by 13 % and sphingomyelin by 23 %). At the same time a decrease in the content of acid phospholipids belonging to membrane inner layer was ob- served (phosphatidylethanolamine by 16 %, phosphatidyl serine by 14 % and monophosphoinositide by 23 %). The data obtained indicate that erythrocyte membrane under stress conditions undergoes certain structural changes which seem to have an effect on its functional properties. At the same time it was fo- und that the content of saturated, unsaturated and ounsaturation index? of fatty acids does not undergo es- sential changes under stress exposure studied thereby, possibly, compensating maintenance of functional properties of the erythrocyte membrane under conditions of the impaired phospholipid structure. On the basis of examining absorption spectra of lipid extracts it was found that stress evokes a two-fold spectrum growth in the range of 390-410 nm appropriate to the hem. The fact of appearance of the hem in the ext- ract indicates to saponification of hemoglobin evoked by changed pH of the erythrocyte internal environ- ment. Actually, in the process of lipid extraction the hemoglobim passes into a disordered state due to the effects of not only temperature and environmental pH but also due to those of organic solvents possessing lower, than water, ability to form hydrogen bonds. Probably, transesterification of a minor portion of phospholipids occurs during their extraction from erythrocytes with the chloroform-methanol mixture.

[PHOSPHOLIPIDS AND FATTY ACIDS IN ERYTHROCYTES OF THE LAMPREY LAMPETRA FLUVIATILIS DURING AUTUMN PRESPAWNING PERIOD AND THE ABSORPTION SPECTRUM OF THEIR LIPID EXTRACT].

The content of some classes of phospholipids and their fatty acid composition in erythrocytes of the lamprey Lampetrafluviatilis during the autumn period of its prespawning migration are investigated. It is found that the phospholipid spectrum of erythrocytes of the lamprey, the oldest representative of vertebrates, is similar to that of many mammals. A four-fold prevalence of phosphatidilcholine content over sphingomyelin content as well as prevalence of (ω3-acids over ω6-acids indicates the <> of lamprey's erythrocyte membranes - an important indicator of deformational ability of lamprey's erythrocytes. Phosphatidilethanol amine and its plasmalogenic form are the most unsaturated phospholipids (their unsaturation indices are 230 and 342, correspondingly). Phosphatidilcholine is the most saturated one (UI is 167). It is found that the basic acid indicators characterizing the fluidity of erythrocyte membranes remain unchanged during the whole period of prespawning migration of lampreys up to spawning. The blood contains several buffer systems, in particular, membrane phospholipids which neutralize acids and alkali incoming into the blood. In the process of organism life a change of pH inside erythrocytes occurs. One can suppose that the base of the system associated with buffer properties of the blood is water dissociation. Inside thin vessels of the circulatory system the hemoglobin attaches and returns molecules of oxygen due to interaction of the buffer systems with water. The property of water to dissociate as well as ion transfer produce in erythrocytes, lying within narrow vessels of the circulatory system, a local pH alteration allowing displacing/attaching the molecule of oxygen from hemoglobin.

[Fatty acid composition of phospholipids of erythrocytes of lamprey, frog, rat, and absorption spectra of their lipid extracts].

The work deals with study of content and fatty acid composition of phospholipids as well as of absorption spectra of lipid extracts of blood erythrocytes poikilothermal and homoiothermal animals of different evolutionary levels. Objects of study were poikilothermal lamprey (Lampetra fluviatilis) consuming oxygen from water and the common frog (Rana temporatia) consuming it both from water and from air. Homoiothermal animals were white rats (Rattus rattus) inhabiting in the air medium. The animals were studied at the winter-spring periods. There was established the twofold predominance of the phospholipid content in the lamprey plasma as compared with erythrocytes. In frog and rat the reverse ratio was observed. Based on study of the fatty acid composition of erythrocyte phospholipids it is suggested the higher density of membranes of lamprey as compared with frog membranes. As to fatty acides of the rat blood erythrocytic fraction, they turned out to be less diverse, with almost twofold predominance of saturated over unsaturated acids and not containing the long-chained (C22) Ω3 acids. All this leads to the low unsaturation index and, accordingly, to a dense packing of fatty acids in membrane structures of rat erythrocytes. Mechanism of reversible binding of O2 molecules by hemoglobin in erythrocytes is discussed. The mechanism of interaction of O2 molecules with water molecules is likely to interfere with exchange interaction electrons of hemoglobin iron atoms and oxygen molecule. This confirms our obtained absorption spectra showing that in the lipid extract practically not containing water the heme isolated from erythrocytes is converted to hemin.