Andrei N Tsentsevitsky

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The effects of high-frequency nerve stimulation (10-100 Hz) on the kinetics of evoked acetylcholine quanta secretion from frog motor nerve endings were studied. The amplitude and temporal parameters of uni- and multiquantal endplate currents were analysed to estimate the possible changes in the degree of synchrony of quantal release. The frog neuromuscular(More)
Reactive oxygen species (ROS) are potent regulators of transmitter release in chemical synapses, but the mechanism of this action remains almost unknown. Presynaptic modulation can change either the release probability or the time course of quantal release, which was recently recognized as an efficient mechanism determining synaptic efficiency. The(More)
The kinetics of neurotransmitter release was recognized recently as an important contributor to synaptic efficiency. Since adenosine is the ubiquitous modulator of presynaptic release in peripheral and central synapses, in the current project we studied the action of this purine on the timing of acetylcholine quantal release from motor nerve terminals in(More)
303 Calcium ions entering into the nerve terminal through voltage-dependent calcium channels during action potential initiate neurotransmitter release and thereby play an important role in the transmission of excitation. In addition to the amount of released neurotransmitter quanta (the quantal content of the endplate potential), another important(More)
A number of different types of presynaptic receptors was revealed in central and peripheral chemical synapses activated both by main mediator and co-mediators released simultaneously. Physiological significance and mechanisms of functioning of these receptors are not clear yet. They are assumed to provide negative or positive feedback decreasing or(More)
We investigated the effects of repetitive high-frequency (10 sec-1) nerve stimulation on the time course of evoked and miniature end-plate currents (EPC and mEPC, respectively) in the frog neuromuscular junction. The data obtained indicate that at a physiological Ca2+ level in the bath medium, 10 sec-1 stimulation results in prolongation of the growth phase(More)
73 Increase in the intracellular level of Ca2+ concen tration leads to the initiation of a wide range of mole cular processes, including the activation of Ca2+ dependent enzymes, gene expression, neurotransmit ter release, etc. [1]. In spite of the variety of channels and pumps involved in the regulation of the intracellu lar Ca2+ metabolism, the main role(More)
5 We have earlier demonstrated that in the course of high frequency stimulation of the motor nerve changes in amplitude of the endplate successive potentials (currents) are not only related to variation of the quantal content of synaptic responses, but also result from asynchronous release of acetylcholine (ACh) in individual active zones [1]. Since high(More)
Experiments on frog neuromuscular junctions have demonstrated that asynchrony of the acetylcholine quantal release forming the multi-quantal evoked response at high-frequency synaptic activity is caused, in particular, by a decrease in velocity of the action potential propagation along the non-myelinated nerve endings, which is mediated by activation of the(More)
Muscarinic cholinoreceptors regulate the neurosecretion process in vertebrate neuromuscular junctions. The diversity of muscarinic effects on acetylcholine (ACh) secretion may be attributed to the different muscarinic subtypes involved in this process. In the present study, the location of five muscarinic receptor subtypes (M1, M2, M3, M4 and M5) on the(More)