did not affect cocaine metabolism through either direct or indirect mechanisms. Similarly, the dramatic reduction in gut bacteria could have potentially resulted in alterations in the HPA axis which could have had confounding effects on our behavioral models. However, when serum levels of corticosterone were measured after a prolonged course of antibiotics there were no significant effects of antibiotic treatment on levels of this stress hormone (Fig. 2c). Based on this, it seems that these studies provided for a model in normally developed mice with a minimum level of added stress.
