By means of mechanotron 6MYIC and perfusion with physiological solution using the "running vesicle", dynamics of functional activity of the popliteal lymph nodes have been studied in 17 non-inbred dogs under conditions of unilateral sympathectomy for 1 week up to 5 months of the experiment. Dependence of the lymph node functional activity on the adrenomediator concentration level in their tissues has been determined by means of the microfluorometry method in the preparations treated after Falck-Hillarp method in E. M. Krokhina modification. Lymph nodes of intact dogs serve as a control. Unilateral sympathectomy of the lymph node is stated to produce an enhancement of the period for its filling and emptying with lymph, resulting from an increased level of the mediator in the fibrillar stroma at the expense of compensatory enhancement of functional activity of the nervous fibers of the contralateral origin. During the remote postoperative period the amplitude of the lymph node capsule fluctuations is stipulated by certain pathomorphological changes, produced by deficiency in concentration of catecholamines in the organ's parenchyma. As to the periodicity of the capsule fluctuations in the intact lymph nodes, it is limited with the cycle of 3-6 min.