Prenatal exposure to low concentrations of carbon monoxide alters habituation and non-spatial working memory in rat offspring

Inhalation of low concentrations (75 and 150 ppm) of carbon monoxide (CO) b y pregnant rats from days 0 to 20 of gestation leads to alterations in habi tuation and working memory in young adult male offspring subjected to the n ovel exploration object test. In particular, lack of habituation upon the s econd presentation of the objects and failure in the ability to discriminat e between the novel and the familiar object were found in CO (75 and 150 pp m)-exposed offspring. These alterations were not accompanied by changes in spontaneous motor activity (open field test). The subtle behavioral deficit s observed in the present study have been produced by prenatal exposure to CO levels resulting in maternal blood carboxyhaemoglobin (HbCO) concentrati ons equivalent to those observed in human cigarette smokers. (C) 1999 Elsev ier Science B.V. All rights reserved.