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Biomedical subjects

V N Frosin

Publications and source records attributed to V N Frosin.

At least 19 recordsLinked to original sources
PubMed2001

Effect of cholinergic agonists on resting membrane potential of earthworm body wall muscle cells.

Carbachol in a concentration of 5x10(-8) mol/liter does not hyperpolarize, and in a concentration of 5x10(-6) mol/liter depolarizes the membrane of somatic muscle cell in earthworm. d-tubocurarine, alpha-bungarotoxin, atropine, and hexamethonium added to the incubation medium did not abolish the carbachol-induced decrease in resting membrane potential. Each of these drugs alone had no effect on resting membrane potential in muscle cells. Presumably, the acetylcholine-sensitive receptor-channel membrane complex in earthworm muscle cell differs from acetylcholine receptor in skeletal muscle fibers and peripheral neurons of vertebrates.

Acetylcholine↗
PubMed1985

[Does non-quantum secretion of acetylcholine from motor neuron endings participate in the neurotrophic control of the membrane potential of muscle fibers in the rat?].

The resting membrane potential of synaptic zone of muscle fibres within 2-3 mm (near) and 9-11 mm (far) of the nerve section of the rat diaphragm muscle was measured after 3 hours or on the 5th day after the motor nerve section. The membrane potential of "near" fibres was lower than that of "far" fibres. The presence of carbamylcholine or cGMP in the culture medium maintained the membrane potential of "near" fibres close to that of "far" fibres. Ouabain prevented these effects. On the 5th day after the nerve section the presence of carbamylcholine or cGMP had no effect on the membrane potential. In the in vitro experiments the nonquantal acetycholine release was equal in "near" and "far" fibres and just the same as in the control preparations. A conclusion is made that synaptic acetylcholine from motor nerve endings in nonquantal form does not play a significant role in neurotrophic control of the resting membrane potential of muscle fibres membrane in mammals.

Acetylcholine↗
PubMed1984

[Non-quantum release of acetylcholine from motor nerve endings and denervation changes in muscle fiber membranes in the rat following blockade of axonal transport].

On the 5th day after blockade of axonal transport with colchicine in rat the resting potential of diaphragm muscle fibre decreased, input resistance increased and the difference between postsynaptic and extrasynaptic membrane in this respect disappeared; extrasynaptic sensitivity to acetylcholine, anode breakdown and tetrodotoxin-resistant action potentials appeared almost in the same form as after nerve section. Application of colchicine to motor nerve, in contrast to nerve section, did not disrupt quantal and non-quantal acetylcholine secretion in motor nerve endings and did not stop muscle contractile activity. The size of non-quantal acetylcholine secretion was estimated by the amplitude of muscle membrane hyperpolarisation in the presence of curare in solution after preliminary acetylcholinesterase inhibition with armin. The data confirm the suggestion that the neurotrophic control of skeletal muscle fibre membrane in mammals is carried out by substances transported to muscle by axonal flow with participation of impulse activity. Synaptic acetylcholine secretion from motor nerve endings in non-quantal form does not play a marked role in neurotrophic control of muscle fibre membrane.

Acetylcholine↗
PubMed1978

[Analysis of the dynamics of the facilitation of end-plate potentials in frogs].

Within 60 msec after presentation of conditioned stimulus the facilitation of the e.p.p. second response declined by two phases. The 1st phase corresponded to the 1st component of facilitation while the 2nd phase followed in 5--10 msec reaching the maximum within 15 msec and then declining with the time constant of 20--50 msec. During repeated stimulation the 1st phase accumulated linearly while the 2nd one exponentially. Tetraethylammonium and three-ethylcholine increased the quantum content e.p.p. and the facilitation but had no effect upon the time constant of the facilitation decline.

Animals↗
PubMed1978

[Polyaxonal innervation of frog phasic muscle fibers].

A cholinesterase activity was revealed in two to four regions of each of the 120 fibers isolated from the frog sartorius muscle, which suggests polysynaptic character of innervation of the phasic muscle fibers. Electrophysiological methods showed the participation of different axons in formation of synapses with a single fiber, as well as the existence of synapses with the correlation between EPP's amplitude and strength of stimulation. The data obtained show such EPPs to be connected with polyaxonal innervation of one region of a muscle fiber.

Acetylcholinesterase↗
PubMedDate not supplied

[Disinfection chambers: Classification and terminology].

To draw up a scientifically-grounded classification of and terminology for the chamber-type disinfection equipment a classificational scheme of notions has been worked out, the most essential characteristics were laid at its basis, such as operational conditions, the shape of the working chamber, the method of charging and disinfection, as well as heating the chamber.

Classification↗
PubMedDate not supplied

[Set of sterilization equipment for large therapeutic institutions].

Some problems concerning the organization of sterilization departments in medical and prophylactic institutions of the Health Ministry of the USSR are discussed. A fundamentally new organizational scheme of work according to the three-zone principle is described. The set of equipment for large sterilization departments is presented. It ensures the operation based on the three-zone system.

Hospital Departments↗
PubMedDate not supplied

[Requirements for operating tables].

Analysis of current medical and engineering requirements for operating tables for adults and children is presented. Special attention is paid to the classification of operating tables, to the requirements for their design, operation, and service. Future trends in development of operating tables are discussed.

Adult↗
PubMedDate not supplied

[Analysis and optimization of major parameters of air sterilizers].

The investigation of the process proceeding in the chamber of an air sterilizer has shown that its design and testing should be performed with the loaded chamber. Petri dishes are advisable to be used as a loading simulator. Thermophysic parameters of sterilizers may be improved through the use of a blower with the blade angle of 40 degrees and the rate of 2400 revs/min.

Air↗