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E A Saĭchenko

Publications and source records attributed to E A Saĭchenko.

2 recordsLinked to original sources
PubMed1990

[Latrotoxin channels. Permeability for divalent cations].

The dependence of Ca2+ transport in synaptosomes along the channels formed by alpha-latrotoxin on [Ca2+]in and the feasibility of transport along these channels of other bivalent cations were studied. It was found that the concentration dependence of Ca2+ influx is nonlinear and is described by the Michaelis-Menten kinetics (Km = 1.07 +/- 0.19 mM). Mg2+, Ba2+, Sr2+, Mn2+ and Co2+ competitively inhibited the Ca2+ influx via latrotoxin channels. Studies with the use of the fluorescent Ca2+ probes, Quin-2 and Fura-2, revealed that these cations can also penetrate inside synaptosomes via latrotoxin channels. The bivalent cation influx via latrotoxin channels caused a decrease of the membrane potential of synaptosomes. The similarity of properties of latrotoxin and endogenous Ca2+ channels is discussed.

Aminoquinolines↗
PubMedDate not supplied

[A high level of cytoplasmic calcium inactivates ion channels, formed by alpha-latrotoxin in the rat brain synaptosomes].

Effect of alpha-latrotoxin on the concentration level of free calcium [( Ca2+]in) in the rat brain synaptosomes and dependence of the activity of "latrotoxin" channels on [Ca2+]in were studied using fluorescent calcium probe quin-2. It is shown that alpha-latrotoxin exerts effect on calcium permeability of plasmalemma and does not induce calcium ejection from the intracellular compartments. A lag-period is characteristic of alpha-latrotoxin action. A degree of the [Ca2+]in increase in synaptosomes depends on the toxin concentration. When [Ca2+]in increases as a result of preliminary potassium depolarization of plasmalemma of synaptosomes, the amount of incoming calcium ions followed by the toxin effect as well as the calcium input rate considerably decrease. Inactivation of calcium-transferring channels induced by alpha-latrotoxin is not a result of a change in the potential on the membrane, as during the blockage of potential-depending calcium channels by D-600, an increase of KCl in the incubation medium does not influence the alpha-latrotoxin action. Differences in the properties of alpha-latrotoxin channels are discussed in synaptosomes and BLM.

Animals↗