A dose-response study of chronic cocaine on maternal behavior in rats.

To determine if there was a dose-response relationship with regard to cocaine treatment and maternal behavior exhibited by lactating rats at doses that had not been previously investigated, we examined the effects of three doses of chronic cocaine administration throughout gestation on both onset and established maternal behavior. Dams were injected (SC) with 6.3, 13, or 25 mg/kg cocaine HCl or an equivalent volume of saline throughout gestation; maternal behavior was tested on postpartum days 1 and 3. At the doses employed, cocaine disrupted the onset of only one pup-directed component of maternal behavior significantly in a dose-response manner, although there were several statistically nonsignificant dose-dependent trends of behavioral disruptions. No pup-directed behaviors were disrupted during testing for established maternal behavior. These results indicate that gestational cocaine treatment at doses of 25 mg/kg and less have only minimal effects on the onset and no effect on the maintenance of maternal behavior using our paradigm. The relationship of the present findings to previous work is discussed.