[A role of the autonomic nervous system in alterations of blood pressure and heart rate induced by 1, 1, 1-trichloroethane (author's transl)].
An experiment was conducted to clarify effect of 1, 1, 1- trichloroethane (1, 1, 1-TCE) on blood pressure and heart rate, and to investigate the role of the autonomic nervous system in these responses. Adult mongrel dogs were anesthetized with sodium pentobarbital (25-30 mg/kg, i. v.) and the respiration was maintained artificially with positive pressure ventilation. Fifty mg/kg of 1, 1, 1-TCE was intravenously injected. The left kidney was exposed by flank incision, and discharges of efferent renal sympathetic nerve were recorded using bipolar platinum electrodes. 1, 1, 1-TCE induced 39.6 +/- 3.1% (mean +/- S. E.) diminution in systemic blood pressure compared to each pre-administration level, but the blood pressure gradually returned to the control level in the vagi intact group. A fall in blood pressure to 39.3 +/- 5.1% level was induced by 1, 1, 1-TCE in the group which had been bilaterally vagotomized or treated with atropine, but it was not significantly different from that in the vagi intact group. Immediately after the administration of 1, 1, 1-TCE, heart rate significantly decreased from 122, 3 +/- 9.1 to 86 +/- 5.6 beats/min in the vagi intact group, but remained unchanged in the vagotomy or atropine group. Discharges of efferent renal nerve were augmented and blood pressure fell, after injection of nitroglycerin. A decrease in the discharge of efferent renal sympathetic nerve and an increase in the blood pressure were observed after injection of norepinephrine. On the other hand, discharges obviously decreased dispite a fall in the blood pressure after administration of 1, 1, 1-TCE. This response showed that the decrease of efferent renal sympathetic nerve activity may be related to the fall in the blood pressure after 1, 1, 1-TCE. On the basis of the results obtained, it is suggested that the autonomic nervous system may play a major role in the effects of 1, 1, 1-TCE on the blood pressure and heart rate in anesthetized dogs.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects*; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D007668:Kidney / Q000294:innervation; D008297:Male; D014240:Trichloroethanes / Q000633:toxicity*; D014628:Vagotomy
D006843:Hydrocarbons, Chlorinated; D014240:Trichloroethanes; C024566:1,1,1-trichloroethane; D001285:Atropine