Developmental neurotoxicity of carbon monoxide.

The results of recent studies dealing with behavioral and electrophysiological dysfunctions induced in rat offspring by prenatal exposure to relatively mild CO concentrations (75 and 150 ppm) have been reviewed in the present paper. In particular, gestational exposure to CO produced the following behavioral changes: (i) reduction in the minimum frequency of ultrasonic calls emitted by rat pups removed from their nest; (ii) decrease in ultrasonic responsiveness to a challenge dose of diazepam; (iii) alterations in the acquisition of an active avoidance task. The electrophysiological changes induced by prenatal CO in peripheral nervous system are as follows: (i) increase in time constants of sodium current inactivation; (ii) increase in the percentage of the maximum number of activatable sodium channels at the normal resting potential; (iii) negative shift of sodium current reversal potential. Moreover, results of ongoing researches on peripheral myelinogenesis in rats exposed to CO during gestation will be also summarized.