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2251186 
Technical Report 
Connection Between Central Action of Glyceryl Trinitrate and Monoamine Metabolism of the Brain 
Kaverina, NV; Vysotskaya, NB; Rozonov, YB; Shugina, TM 
1967 
NIOSH/00132762 
64 
12 
51-55 
The mechanism of action of glyceryl-trinitrate (55630) (GTN) on processes of central regulation of vascular tone was investigated in cats. Specific methods were not stated. Recordings of tonic and reflex activity in the inferior cardiac nerve were conducted on anesthetized cats. Mechanoreceptors of the carotic sinus were stimulated to determine the effect of GTN on reflex inhibition. Noradrenalin concentrations were determined in various parts of the brain by spectrofluorometry. The effect of GTN on vasomotor reflexes was investigated. A 1 milligram per kilogram (mg/kg) dose of GTN depressed spontaneous electrical activity and reflex discharges in the inferior cardiac nerve. Vasomotor reflexes were depressed. The effect lasted for 30 to 35 minutes. These reactions were analogous to those found with monoamines. GTN was injected 4 hours after reserpine (50555). The action of GTN confirmed that it was independent of monoamine liberation. The intensity of vasomotor reflexes were unchanged. Injection 24 hours after reserpine caused GTN to inhibit the vasomotor reflexes. Noradrenalin concentrations in brain tissue were reduced 50 to 70 percent after injection of 1mg/kg GTN. Recovery began after 2 hours and noradrenalin returned to normal after 4 hours. GTN caused the intensity and duration of reflex inhibition of tonic activity in the sympathetic nerves of the heart to rise sharply. The effect lasted 30 to 35 minutes. The authors conclude that the mechanism of the central action of GTN on tonic and reflex activity of the sympathetic nervous system and on vasomotor reflexes is associated with its influence on biogenic monoamines. (Russian)