Anderson Karen G, Woolverton William L
Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
Psychopharmacology (Berl). 2003 Jun;167(4):424-30. doi: 10.1007/s00213-003-1435-9. Epub 2003 Apr 11.
Drug abuse is often considered a problem related to impulse-control disorders, but little is known about the factors that determine the choice to self-administer a drug in a self-control/impulsivity paradigm.
The objective of the present study was to evaluate choice between a low dose of cocaine administered after a relatively short delay (impulsive option) and a high dose of cocaine following a relatively longer delay (self-control option).
Rhesus monkeys self-administered intravenous cocaine in a discrete-trials choice procedure. First, choice was between different 3:1 doses (0.3/0.1 and 0.1/0.03 mg/kg per injection) following equal 30-s delays to infusion. Second, choice was between equal doses (0.1 mg/kg per injection) following 3:1 delays (30 s/10 s, 90 s/30 s, 270 s/90 s, 810 s/270 s). Third, choice was between 0.1 or 0.03 mg/kg per injection after the same 3:1 delays with the larger dose following the longer delay and the smaller dose following the shorter delay. Fourth, the same 3:1 delays were used to study choice between 0.3 and 0.1 mg/kg per injection.
With equal delays, the larger dose of cocaine was chosen almost exclusively, and with equal doses, the shorter delay was chosen almost exclusively. When both dose and delay were manipulated, mean large-dose (0.1 mg/kg per injection) choices for three of four subjects was 98% when the delays were the shortest (30 s/10 s), but this preference reversed as the delays increased, so that 74% of choices were for the smaller dose (0.03 mg/kg per injection) at the longest delays (810 s/270 s). This systematic decrease in large-dose choices as the absolute, but not relative, values of the delays were increased, was also observed with the higher dose combination.
Delay discounting was supported by the present findings in that the value of a large reinforcer (higher cocaine dose) was decreased as its delay to presentation was increased. The importance of not only relative, but absolute, values of delays to drug reinforcement in determining drug choice was also demonstrated. Thus, a self-control/impulsivity paradigm can be extended to conditions with non-human subjects and drug reinforcers.
药物滥用通常被视为与冲动控制障碍相关的问题,但对于在自我控制/冲动范式中决定自我给药选择的因素知之甚少。
本研究的目的是评估在相对较短延迟后给予低剂量可卡因(冲动选择)和在相对较长延迟后给予高剂量可卡因(自我控制选择)之间的选择。
恒河猴在离散试验选择程序中自我静脉注射可卡因。首先,在给予相同30秒延迟至注射的情况下,在不同的3:1剂量(每次注射0.3/0.1和0.1/0.03毫克/千克)之间进行选择。其次,在3:1延迟(30秒/10秒、90秒/30秒、270秒/90秒、810秒/270秒)后,在相同剂量(每次注射0.1毫克/千克)之间进行选择。第三,在相同的3:1延迟后,在每次注射0.1或