[Effect of acute blood loss on catecholamine balance in the pulmonary circulation in anesthetized rats]

The contribution of pulmonary inactivation of catecholamines (CA) in the formation of their level in circulating blood during the development of a posthemorrhagic reaction was studied. Pulmonary CA inactivation was evaluated according to the arteriovenous difference (right ventricle and carotid artery) in epinephrine (E) and norepinephrine (NE) whose concentration was determined by the method of highly-effective liquid chromatography with electrochemical detection. Reciprocal phase changes in the dynamics of the arteriovenous difference in NE and E and levels of the corresponding CA in arterial blood plasma were discovered during the development of the posthemorrhagic reaction. Pulmonary inactivation of CA increased by the 2nd minute, then dropped below the initial level with subsequent restoration. The NE level in the arterial blood plasma was marked by a strictly contrary dynamics, while the concentration of E reached maximum when inactivation of E in the lungs was minimal (5th minute). The mechanisms and physiological significance of the discovered phenomenon are discussed.