AUTONOMIC TONUS REGULATION DISORDERS IN RATS WITH A TRANSPLANTED TUMOR PC-1
By means of analysis of the heart rate variability method (HRV) it was discovered that the HRV rates (total capacity of the Tp spectrum, the squared deviation SDNN, high-frequency component HF) of the rats, which had the implanted tumor PC-1 were decreasing in comparison with the control group (the rats without a tumor), which indicated a significant sympathizing of the vegetal tonus. The use of stress-tests (the orthostatic test, short-term immobilization) led to statistically significant variation of HRV rates, which also differed from the control group. It was demonstrated that the low-frequency components LF of the spectrum of the tumor-bearing animals decreased in response to functional stress, which signified the disorder of tonus regulation in autonomic nervous system, i.e. the changing of sympathizing over to parasympathizing, the breakdown of adaptive response.