In the postresuscitation period through the I-II-III-IV-V-stages and long-term periods (1 and 3 months) of postresuscitation illness, when modeling a 10-minute clinical death, we studied the relationship between the reactivity of the autonomic nervous system and the morphofunctional activity of neurosecretory cells of the arcuate nucleus of the hypothalamus of white mature rats - males, weighing 180-220 grams, who underwent a 10-minute arrest of systemic circulation (clamping of the vascular bundle of the heart according to the method of V.G. Korpachev). Sham-operated animals served as control. Physiological, morphological, morphometric, histochemical, cytophotometric studies of the state of reactivity of the autonomic nervous system and morphofunctional activity of neurosecretory cells of the arcuate nucleus of the hypothalamus were carried out. We used image analysis using a Leiss microscope with an electronic micro-attachment connected to an Intel computer, and the content of neurosecretory substances was studied using a cytophotometer. In the postresuscitation period, during stage I, hyperhydration of the cytoplasm of neurosecretory cells of the arcuate nucleus of the hypothalamus was revealed against the background of the predominance of the tone of the parasympathetic nervous system. During stage II of the predominance of the tone of the parasympathetic nervous system, starting from stage III of the disease, against the background of the predominance of the tone of the sympathetic nervous system, hyperhydration of the nuclei of neurosecretory cells of the arcuate nucleus of the hypothalamus is observed with an increase in the release of neurosecret into the blood, i.e., compensatory-adaptive reactions were observed. Compensatory-restorative processes with a shift towards depletion of neurosecretory cells of the arcuate nucleus were observed starting from stage IV and in the remote periods of postresuscitation disease against the background of the predominance of the tone of the sympathetic nervous system and overhydration of the nuclei.