Fig. 8.   Noradrenergic hypoactivity elicited by prenatal nicotine exposure. Norepinephrine content and turnover are suppressed in the nicotine group, involving both the initial postnatal period, and after a transient recovery to normal, a secondary period of persistent hypoactivity (Navarro et al., 1988). Before the reemergence of deficits in the measures of basal activity, the nicotine group shows a subnormal responsiveness to acute challenges. A single injection of nicotine, which releases norepinephrine in the control group, fails to do so in the nicotine group (Seidler et al., 1992b). CON, control; NIC, nicotine.