Biomedical subjects
Publications and source records attributed to G M Boriskina.
Both acetylcholine and eserine affect Ca2+-binding to mammalian erythrocyte membranes. Differences in Ca2+-binding between normotensive and hypertensive groups (human as well as rats) was found under eserine influence.
The effect of the beta-adrenoblocker propranolol on adrenaline-stimulated lipolysis was studied in the adipose tissue of spontaneously hypertensive rats (SHR) and control rats. The lipolytic activity was estimated from the increase in glycerol concentration in the incubation medium in vitro. The adipose tissue of SHR responded to adrenaline similarly to that of control rats, but the concentration of adrenaline inducing the half-maximum response (KA) was 2 times less for SHR than KA for normotensive controls. Under propranolol effect this parameter was increased more significantly in SHR than in controls. These data indicate higher sensitivity of SHR adipose tissue to propranolol that may well be relative to alteration of the properties of beta-adrenergic receptors of adipose tissue in this form of hypertension.
The increase of the content of triphosphoinositide in the erythrocyte membrane in rats with spontaneous and renal hypertension and decrease of phosphatidylinositol at spontaneous hypertension were revealed.
Effect of some 3- and 4-substituted pyridines on enzymatic hydrolysis of NAD by rabbit heart muscle NAD-glycohydrolase has been studied. It is shown that some 4-substituted derivatives in contrast with 3-substituted ones produce an inhibitory effect on the enzyme activity. A new efficient inhibitor of rabbit heart muscle NAD-glycohydrolase (I50 = 10(-3) M)--N1-(2-lactyl)-N2-(isonicotinoy)hydrazine, inducing uncompetitive inhibition of hydrolysis of NAD is found. The mechanism of the inhibitory effect of N1-(2-lactyl)-N2-(isonicotinoyl)hydrazine was investigated and the rate equation for enzymatic hydrolysis of NAD in the presence of inhibitor is calculated. It is suggested, that the inhibitory effect of N1-(2-lactyl)-N2-(isonicotinoyl)hydrazine is due to the formation of triple inactive complex inhibitor-enzyme-adenosinediphosphateribose.
The values of triphosphoinositides (TPI) and monophosphoinositides (MPI) contents per 1 mg of membrane protein in the erythrocyte hosts of spontaneously hypertensive rats (SHR) constitute 178 and 74%, respectively, of that in the erythrocyte hosts of normotensive rats (NR). The total amount of phosphoinositides in the erythrocyte hosts of NR is more than 120% of the total amount of these lipids, in the erythrocyte hosts of SHR.
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The activities of the Na+--K+-ATPase, succinic dehydrogenase (SDH/, lactic dehydrogenase (LDH/ and glucose-6-phosphat dehydrogenase (G-6-PDH/ were studied in the cortex outer and inner medulla of the kidneys of rats with spontaneous hypertension (SHR) and were compared with those of control normotensive Wistar rats. The SHR aged 6--8 weeks had durint the prehypertensive and the early hypertensive stage the same enzymatic activities as control rats. Rats with a steady SH aged 16-22 weeks had low specific activity of the, Na+--K+-ATPase, SDH and LDH in the outer medulla. The latter can be associated with decreased intensity of the energy metabolism and a reduction of the active sodium transport in the ascending limb of the loop of Henle in the SHR rats and cold cause the phenomenon of exaggerated natriuresis characteristic of hypertension.
Methods of isolation of NAD-glucohydrolase from the fraction of heart microsomes were searched for. NAD-glucohydrolase proved to pass into a soluble state under the effect of phospholipase A, triton X-100 and Na cholate. NAD-glucohydrolase was found to possess peculiar properties; it reversibly became denatured under the effect of 6M urea, but failed to become inactivated with own substrate (NAD) at pH 8.0. In case of NAD-ases isolated from other sources the reversible denaturation by means of urea as a rule correlated with the enzyme inactivation in the presence of NAD at pH 8.0.