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Pochaev V.A.,Russian Academy of Sciences | Krasnyi A.M.,Institute of Medical and Biological Problems | Ozernyuk N.D.,Russian Academy of Sciences
Biology Bulletin | Year: 2013

Voltage-dependent L-type Cav1.3 channels have been detected in satellite cells localized to muscle fibers. It was established that the action of carbachol, which activates nicotinic acetylcholine receptors and causes cell membrane to depolarize, resulted in the activation of these channels. In addition, verapamil and amlodipine, selective L-type calcium channel blockers, suppressed extracellular calcium influx into the cytoplasm. It was noted that in a calcium-free medium, carbachol had no influence on the concentration of calcium in the cytoplasm of satellite cells, whereas adrenaline induced calcium efflux from intracellular stores. In addition, calcium influx into the cytoplasm was not suppressed by verapamil and amlodipine under the action of adrenaline and noradrenalin in a medium with calcium, and an ICI-118551 blocker of β2-adrenoreceptros significantly decreased the increase in the concentration of calcium in the cytoplasm. © 2013 Pleiades Publishing, Ltd.

Kartashov D.A.,Institute of Medical and Biological Problems | Shurshakov V.A.,Institute of Medical and Biological Problems | Kolomenskii A.V.,Institute of Medical and Biological Problems
Cosmic Research | Year: 2011

To estimate the protective properties of a space suit against cosmic radiation the dose rates were calculated for extravehicular activity in the ISS orbit for a number of representative points of critical organs of the human body. The screening functions of the Orlan-M space suit obtained by the authors earlier are used in the calculations. In addition, the effect of East-West asymmetry of the fluxes of high-energy protons trapped by the geomagnetic field is taken into account. It is shown that during passages through the South Atlantic Anomaly, choosing the optimal orientation of astronauts in relation to the cardinal directions, one can achieve for the most critical body organs a dose rate reduction by a factor of ~1. 5-1.8 (in the maximum of solar activity) and by a factor of ~2-2.5 (in the solar activity minimum). The obtained results can serve for obtaining more accurate estimation of radiation risk for astronauts working in the Orlan-M space suit in the near-terrestrial orbits and for elaborating practical recommendations to reduce their radiation exposures. © 2011 Pleiades Publishing, Ltd.

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