Archival ReportEndocannabinoids Promote Cocaine-Induced Impulsivity and Its Rapid Dopaminergic Correlates
Section snippets
Subjects and Surgery
Thirty-six male Long-Evans (Charles-River, St. Constant, Quebec, Canada, or Wilmington, Massachusetts) rats weighing 300 to 350 g at the time of arrival, served as subjects. Rats were individually housed in a temperature- and humidity-controlled room with a 12-hour light-dark cycle (lights on at 07:00 hours). Animals were divided as follows: 18 rats were used in the reversal experiment; 12 of those received cocaine and 6 received saline. The remaining 18 were used in the blockade experiment. Of
Blockade of CB1 Receptors Reverses Cocaine-Induced Changes in Preference for the Large Reward
The initial injection of cocaine produced similar increases in locomotor activity in both groups, the group that would be injected with the CB1R antagonist and the one injected with vehicle (t10 = −1.17, p = .26). Rats of both groups were sensitized to the locomotor effects of cocaine (t5 vehicle-group = 2.86, p = .035; t5 CB1 blockade-group = 3.32, p = .020) (Figure 1A,B; Figure S2 in Supplement 1). Saline-injected rats showed no statistical difference between the first and last saline
Discussion
The current study documents the role of eCBs in the development and maintenance of changes in impulsive choice that arise from cocaine exposure and adds to a growing body of evidence related to the modulatory role that eCBs play in self-control—in particular when it is altered by psychostimulants 72, 73, 74. We demonstrate that cocaine produces a decrease in self-control that is reversed and blocked by interfering with CB1R signaling. Rats exposed to cocaine show a preference for immediate
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