ABSTRACT
Beta-endorphin, metenkephaline, and ACTH were radioimmunoassayed in the peripheral blood plasma of 4 groups of patients subjected to microsurgery by different techniques. In 3 groups electropulsed exposure of the CNS was a component of general combined ataralgesia. In group 1 (13 patients) two Lenar devices were employed, in group 2 (5 patients) Skat-202 device, in group 3 (7 patients) Elean device. Group 4 (17 patients) were controls administered drugs according to the same protocols as in the rest three groups. Anesthesia was considered adequate in all the groups. The hypoalgesic effect of electroexposure was the most expressed in group 1: fentanyl was not injected in 53% cases, and in 47% its dose, 0.74 microgram/kg/h, was 2.25 times lower than in controls (1.58 micrograms/kg/hm p < 0.05); the drug doses in groups 2 and 3 (0.82 and 0.8 microgram/kg/h) were 1.9 and 2 times lower than in controls, respectively, p < 0.05. The levels of ACTH and opioid peptides were measured at 6 stages: 1) several days before surgery; 2) after premedication, 10-15 min after the patient was brought into the operation room; 3) before discontinuing nitrogen oxide; 4) after discontinuing nitrogen oxide; 5) when the patient regained consciousness after the end of surgery; and 6) after extubation of the trachea. During surgery under electromedicamentous anesthesia the level of ACTH in the plasma was the same as initially or comparable to the level of this hormone at the same stages in the control group. The content of opioid peptides changed at stressogenic stages of anesthesia and surgery. In patients administered drug anesthesia beta-endorphin levels were shifted, in those operated on under electromedicamentous anesthesia the metenkephaline compound of the opiate system was altered. Activation of various components of endogenous opiate system in electromedicamentous and drug anesthesia may be due to differences in the mechanisms of this types of anesthesia at the given level of the antinociceptive system of the organism. No stable reaction of endorphin level on the electroexposure could be detected. There was no evident relationship between changes in the levels of opioid peptides and the decrease of fentanyl consumption. Besides, it is possible that the analgesic effect of electroexposure is mediated not only by the opioid, but by other mechanisms of endogenous antinociceptive system as well.
