Abstinence from cocaine intake induces changes in dopaminergic activity in the VTA after 30 days of withdrawal, but not 1 day of withdrawal
We have previously shown a significant persistent decrease in the dopaminergic population activity recorded in the VTA after 7 and 30 days of abstinence from extended cocaine intake (25 days) (Salin et al., 2021). Here, we investigated potential changes in DA VTA activity after a shorter 10-day period of cocaine self-administration, in the early phase of abstinence (withdrawal days 1-3) and after protracted abstinence (withdrawal days 26-45). An example of the location of the recording electrode at the end of a recording is presented inĀ Figure 2A. Population activity (Figure 2B), firing rate (Figure 2C) and percentage of spikes firing in bursts (Figure 2D) were analyzed for VTA DA neurons in saline/naive and cocaine rats after 1-3 and 26-45 days of abstinence. Exposure to cocaine induced a significant decrease in population activity of VTA DA neurons during long-term but not short-term abstinence, compared to saline/naive rats (Figure 2B). Post-hoc analysis revealed a significant difference between saline/naive WD1-3 and cocaine WD26-45, saline/naive WD26-45 and cocaine WD26-45 and cocaine WD1-3 and cocaine WD26-45. There was no change in the firing rate (Figure 2C), but a significant drug effect was observed for the percentage of spike firing in bursts (Figure 2D) of DA neurons between groups.