Effects of the NMDA receptor antagonists dizocilpine and Ro 63-1908 on delay-discounting and risky decision-making in a gambling task.

Effects of the NMDA receptor antagonists dizocilpine and Ro 63-1908 on delay-discounting and risky decision-making in a gambling task.
Behav Brain Res. 2018 Apr 21;:
Authors: Higgins GA, Silenieks LB, MacMillan C, Zeeb FD, Thevarkunnel S
Abstract
Previous studies demonstrated that NMDA receptor antagonists such as dizocilpine (MK801) and the GluN2B NMDA antagonist Ro 63-1908 promote impulsive action (motor impulsivity). The effects of these treatments on impulsive choice and decision-making is less well characterized. Two experiments were undertaken. In the first experiment, given evidence for delay order as a factor in choice selection, the effect of dizocilpine was examined in a delay discounting task with separate groups of male Long-Evans rats trained to a schedule of either ascending (i.e. 0-40s), or descending delays (i.e. 40-0s). Under the ascending-delay schedule, dizocilpine (0.03-0.06 mg/kg SC) reduced discounting, yet on the descending-delay schedule discounting was increased. Subgrouping rats according to discounting rate under vehicle pretreatment were consistent with a treatment-induced motor perseveration. In a second experiment, male Long-Evans rats were trained to a gambling task (rGT). Neither dizocilpine (0.01-0.06 mg/kg SC) nor Ro 63-1908 (0.1-1 mg/kg SC) shifted choice from the advantageous to the disadvantageous options. However dizocilpine, and marginally Ro 63-1908, increased choice of the least risky, b...

Source: Behavioural Brain Research - April 21, 2018 Category: Neurology Authors: Higgins GA, Silenieks LB, MacMillan C, Zeeb FD, Thevarkunnel S Tags: Behav Brain Res Source Type: research