Differential effects of glutamate N-methyl-D-aspartate receptor antagonists on risky choice as assessed in the risky decision task.
Psychopharmacology (Berl) 2021;
238:133-148. [PMID:
32936321 PMCID:
PMC7796939 DOI:
10.1007/s00213-020-05664-z]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/10/2020] [Indexed: 12/15/2022]
Abstract
RATIONALE
Risky choice can be measured using the risky decision task (RDT). In the RDT, animals choose between a large, risky option that is paired with probabilistic foot shock and a small, safe option that is never paired with shock. To date, studies examining the neurochemical basis of decision-making in the RDT have focused primarily on the dopaminergic system but have not focused on the glutamatergic system, which has been implicated in risky decision-making.
OBJECTIVES
Because glutamate is known to play a critical role in decision-making, we wanted to determine the contribution of the glutamatergic system to performance in the RDT.
METHODS
In the experiment, 32 rats (16 male; 16 female) were tested in the RDT. The probability of receiving a foot shock increased across the session (ascending schedule) for half of the rats but decreased across the session (descending schedule) for half of the rats. Following training, rats received injections of the N-methyl-D-aspartate (NMDA) receptor competitive antagonist CGS 19755 (0, 1.0, 2.5, 5.0 mg/kg; s.c.) and the GluN2B-selective antagonist Ro 63-1908 (0, 0.1, 0.3, 1.0 mg/kg; s.c.).
RESULTS
CGS 19755 (2.5 and 5.0 mg/kg) increased risky choice in males and females trained on the ascending schedule. Ro 63-1908 (1.0 mg/kg) decreased risky choice, but only in male rats trained on the ascending schedule.
CONCLUSIONS
Although NMDA receptor antagonists differentially alter risky choice in the RDT, the current results show that NMDA receptors are an important mediator of decision-making involving probabilistic delivery of positive punishment.
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