Respiratory Disorders following 1,1,1-Trichloroethane Inhalation: A Role of Reflex Mechanism Arising from Lungs

Abstract

The effects of 1,1,1-trichloroethane (1,1,1-TCE) inhalation on respiration and afferent activity of the lung stretch receptor were investigated in anesthetized dogs. In acute inhalation experiments, rapid and shallow breathing was observed following inhalation of high 1,1,1-TCE concentrations. The threshold concentration of 1,1,1-TCE to produce an increase in respiratory rate was approximately 0.9% in inspired air. Moreover, a dose-response relationship was observed between the increase in respiratory rate and concentrations which exceeded the threshold level. An inspiratory action of respiration markedly decreased for high 1,1,1-TCE concentrations. Both the increase in respiratory rate and the decrease in the inspiratory action for high 1,1,1-TCE concentrations were significantly inhibited, however, these reactions were not completely blocked by bilateral vagotomy. Afferent impulses of the lung stretch receptor in the vagus nerve obviously increased following 1,1,1-TCE whose concentrations were more than 0.9% in inspired air. It is suggested that rapid and shallow breathing following higher 1,1,1-TCE concentrations may be related to the increase in the activity of the lung stretch receptor. It is further suggested that a part of rapid and shallow breathing is not based on anesthetic effects but enhancement of Hering Breuer reflex following 1,1,1-TCE inhalation.