Supplementary Figure 10: Escalation of cocaine intake and effects of L-DOPA during LgA over 6 h of cocaine self-administration.
From: Excessive cocaine use results from decreased phasic dopamine signaling in the striatum
a, LgA animals showed a significantly increasing number of active nose pokes during six hours of cocaine self-administration across weeks (n = 24). b, Non-escalated animals (n = 10) showed no significant increase in cocaine intake during six hours of self-administration over the course of LgA (closed circles), whereas escalated rats (n = 14) increased their intake significantly (open circles). c, A single i.v. injection of L-DOPA (30 mg/kg) and Benserazide (2 mg/kg) prior to session start decreased the escalated number of active nose poke responses (purple bar) to a number (open purple bar) comparable to the pre-escalation stage (orange bar; n = 5). d, Repeated i.v. administration of L-DOPA (30 mg/kg) and Benserazide (2 mg/kg) on five consecutive days reliably reduced the escalated number of active nose poke responses (purple bar) and maintain the responses at a rate (open purple bar) comparable to the pre-escalation stage (orange bar; n = 5). Data are mean + SEM. *P<0.05. **P<0.01.
