出版社：National Institute of Occupational Safety and Health
摘要：The acute effects of carbon monoxide (CO) exposure on a steady-state operant behavior (bar-pressing under a VI 60-sec schedule of food reinforcement) were repeatedly measured in (a) rats exposed to various concentrations of CO (500, 1, 000, 1, 500 and 2, 000 ppm) for 1h and (b) rats exposed to 1, 500ppm for different periods (1, 2 and 4h). Measurements were made continuously before, during and after the exposure period. Abrupt cessation of the response was produced by exposure to 1, 000ppm or higher concentrations of CO. Recovery from the effects of CO exposure was observed as sudden resumption of responding during the post-exposure period. The duration of exposure required to produce response inhibition was closely correlated with the exposure concentration. The post-exposure interval required for response recovery was also correlated with the exposure concentration. This post-exposure response recovery interval, however, was constant and independent of the duration of exposure when the concentration was fixed at 1, 500ppm. In order to correlate these behavioral changes with an internal index of CO exposure, blood carboxyhemoglobin (HbCO) levels were determined under several exposure conditions corresponding to those of the behavioral observations. It was found that HbCO levels were within a certain range (33-43%) when response recovery occurred, suggesting the existence of a critical HbCO level (threshold) associated with the drastic behavioral change. Hence, these results support the view that blood HbCO is an important determinant of the acute behavioral effects of CO.
