ABSTRACT
A new class of substances exhibiting radioprotective and radiosensitizing effects depending on the concentration of the substance has been found. The radioprotective effect is probably due to the resonant absorption of radiation energy and its transformation into low-energy forms, as well as reactions with water radiolysis products. We studied the effects of 2,5-difeniloxazole and di[2-(5-feniloxazolil)]benzene in various concentrations in conjunction with irradiation on the growth of melanoma B-16 in mice and the average time of their lives. When using individual doses of irradiation and doses of preparations, we observed an increase in the average lifetime of mice and a reduced tumor size. These data allow us to conclude about the possibility of using these substances in the radiotherapy of tumors.
Subject(s)
Benzene Derivatives/pharmacology , DNA/drug effects , Oxazoles/pharmacology , Radiation-Protective Agents/pharmacology , Radiation-Sensitizing Agents/pharmacology , Animals , Benzene Derivatives/chemistry , Cell Membrane/drug effects , Cell Membrane/radiation effects , DNA/radiation effects , DNA Breaks, Double-Stranded/drug effects , Dose-Response Relationship, Radiation , Melanoma, Experimental , Mice , Mice, Inbred BALB C , Oxazoles/chemistry , Radiation-Protective Agents/chemistry , Radiation-Sensitizing Agents/chemistry , Spleen/cytology , Spleen/drug effects , Spleen/radiation effects , Water/chemistry , Whole-Body IrradiationABSTRACT
With the use of microspectrofluorimetry the pH-dynamics in the frog nerve at rest and during rhythmic excitation was investigated. Rhythmic excitation results in an increase of hydrogen ion concentration in the nerve fibres. Metabolic and ion channel inhibitors affect intracellular pH changes. The results obtained suggest different role of various transport systems (sodium pump and ion channels) in the regulation of pH at rest and during rhythmic excitation.
Subject(s)
Sciatic Nerve/chemistry , Animals , Biological Transport , Electric Stimulation , Hydrogen-Ion Concentration , In Vitro Techniques , Ion Channels/drug effects , Lanthanum/pharmacology , Ouabain/pharmacology , Rana temporaria , Rotenone/pharmacology , Sciatic Nerve/drug effects , Sciatic Nerve/physiology , Spectrometry, Fluorescence , Tetrodotoxin/pharmacologyABSTRACT
In the frog nerve, 3H-bungarotoxin and 3H-acetylcholine binding increased whereas the acetylcholinesterase activity decreased in rhythmic stimulation. The enhancement of 3H-bungarotoxin binding to nerve during the rhythmic stimulation seems to stem from transformation of "inactive" forms of acetylcholine receptor of glial membrane to "active" ones.
Subject(s)
Bungarotoxins/metabolism , Nervous System Physiological Phenomena , Neural Conduction , Receptors, Cholinergic/metabolism , Acetylcholine/metabolism , Acetylcholinesterase/metabolism , Animals , Brachyura , Electric Stimulation , Nerve Fibers/physiology , Neuroglia/physiology , Rana temporariaABSTRACT
A decrease of external pH during rhythmic excitation of the nerve of frog and squid was investigated. The level of pH was dependent on frequency excitation, concentration of sodium potassium and hydrogen ions was changed after ouabain, 2,4-dinitrophenol, tetraethylammonium and tetrodotoxin effect. The mechanism of proton transport was discussed in relation to Na-channel function.
