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We studied the effect of short-term swimming in cold water (13 degrees C) on parameters of the blood antioxidant system (activities of superoxide dismutase and catalase, concentrations of ceruloplasmin and nonprotein thiols), heme oxygenase activity, and nonprotein thiol level in mouse liver. The test parameters of antioxidant protection increased 1 h after cold exposure and remained high 1 day after treatment. These changes were accompanied by an increase in the adaptive capacity. After swimming in cold water the resistance of animals to another stress factor (administration of epinephrine) was higher compared to controls.

Hypoxia of various origin and localization is accompanied by changes in some physical and chemical properties of erythrocytes: deformability, plasma membrane viscosity, and the oxygen-binding capacity of hemoglobin [1,[4][5][6]. Under the conditions of brain ischemia, these properties are studied insufficiently. After postischemic reperfusion (PIR) that restores blood circulation, the oxygen partial pressure in plasma increases, which may stimulate the generation of reactive oxygen species (ROS) and affect the erythrocyte functions. In blood plasma, Cu,Zn-superoxide dismutase (SOD) and ceruloplasmin (CP) are involved in utilization of superoxide anion radical ( ) that triggers ROS formation. In this study, changes in the viscosity of erythrocyte plasma membrane and the é 2 -binding ability of hemoporphyrin of deoxyhemoglobin were studied. SOD activity and CP level were also measured in blood plasma of rats with brain ischemia before and after brain PIR.White outbred male rats weighing 272 ± 11 g were used in experiments. The animals were divided into three groups: the sham-operated rats (the control) ( n = 10), the rats with brain ischemia ( n = 10), and the rats with postischemic brain reperfusion ( n = 7). One day before the experiment, both carotids of the anesthetized animals were underpinned with a fishing line (0.3 mm) that was later withdrawn under skin through the polyethylene tubes into the interscapular region. After one day, a one-stage complete occlusion of both carotids was induced by carotid retraction into the tubes by means of the fishing line; subsequent release of carotids led to PIR. Blood samples (3 ml of blood mixed with heparin, 10 U/ml) were taken from the jugular veins of O 2 -the sham-operated rats, the second group rats 2 h after ischemia, and the third group rats 2 h after ischemia that was followed by 30-min PIR.The viscosity of erythrocyte plasma membrane was determined by the method of electron paramagnetic resonance (EPR) on an RE-1308 EPR spectrometer (Russia). The spin-labeled stearic acid analogues, 5-and 16-doxylstearic acids (5-DS and 16-DS), which have a paramagnetic fragment in positions differing with respect to the carboxylic group, served as a spin probe. With these reagents, the orderliness of fatty-acid phospholipid tails can be tested at different depth from the membrane surface (0.6-0.8 nm and about 2.2 nm). The following parameters were calculated from the EPR spectra: (1) the orderliness parameter S for the 5-DS probe, which characterizes the acyl-chain mobility and (2) the correlation time of the nitrooxyl radical rotation τ for the probe 16-DS [3].Changes in the conformation of hemoglobin hemoporphyrin were estimated by combination scattering (CS) spectroscopy [8]. The blood sample in HEPES-Hank's solution (ratio, 1 : 4, pH 7.4-7.5) was placed into a hermetically closable capillary that was fastened in the holder of the device. We used a DFS-24 monochromator (Russia) with excitation from the solid-state Nd-laser ( λ = 473 nm, R = 18-20 mV) and a FEU-79 photon-recor...

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Heme oxygenase catalyzes heme degradation and is an important component of the antioxidant defense. Nonprotein thiols participate in redox regulation of heme oxygenase gene expression. Changes in heme oxygenase activity and levels of nonprotein thiols in the liver, lungs, and brain of C57Bl/6 mice were studied on days 1-7 after whole-body γ-irradiation in a dose of 10 Gy. The maximum increase in heme oxygenase activity was observed in the liver (to 196% in females and to 250% in males) and was associated with an 8-fold increase in the level of heme oxygenase-1 (inducible form of the enzyme) mRNA. The increase in heme oxygenase activity was less pronounced in the lungs, while in the brain this parameter slightly decreased. Changes in the levels of nonprotein thiols were sex-dependent: in the liver and lungs this parameter increased in females and decreased in males.

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We studied the effects of taurine, carnosine, and casomorphine on histamine release from rat peritoneal mast cells induced by compound 48/80 and ionophore A23187. Differences were revealed in the effect of the test preparations. Taurine inhibited histamine release induced by ionophore A23187, but not by compound 48/80. Carnosine abolished the stimulatory effect of compound 48/80 on histamine release, but did not modulate the effect of ionophore A23187. Casomorphine inhibited histamine release induced by ionophore A23187, but potentiated the effect of compound 48/80. The mechanisms for these effects are discussed.