Department of Pharmacology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr - MC 7764, San Antonio, TX, 78229, USA.
South Texas Veterans Health Care System, San Antonio, TX, USA.
Psychopharmacology (Berl). 2021 Mar;238(3):735-744. doi: 10.1007/s00213-020-05726-2. Epub 2020 Nov 24.
A subset of male rats that self-administer 3,4-methylenedioxypyrovalerone (MDPV) have unusually high levels of drug intake; however, factor(s) that influence this behavior (e.g., reinforcement history and sex) are unknown.
Characterize the reinforcing potency and effectiveness of MDPV in female rats to determine whether (1) a subset of females also develop high levels of MDPV self-administration (i.e., a high-responder phenotype) and (2) the degree to which the high-responder phenotype is influenced by various reinforcement histories (i.e., responding for cocaine or food).
Female Sprague Dawley rats initially responded for MDPV (0.032 mg/kg/infusion), cocaine (0.32 mg/kg/infusion), or food (45-mg grain pellet) under fixed ratio (FR) 1 and FR5 schedules of reinforcement. After 20 sessions, the cocaine- and food-history rats responded for MDPV for 20 additional sessions. Dose-response curves for MDPV were generated under FR5 and progressive ratio (PR) schedules of reinforcement.
A subset of rats responding for MDPV developed high levels of MDPV intake. A history of responding for cocaine, but not food, inhibited the development of high levels of MDPV intake. Large individual differences were observed in the level of self-administration when MDPV was available under an FR5, but not PR, schedule of reinforcement.
MDPV functions as a powerful reinforcer in female rats, as has been previously reported in male rats. The substantial variability in MDPV self-administration between subjects may be related to individual differences in human drug-taking behavior.
一小部分自行摄入 3,4-亚甲二氧基吡咯戊酮（MDPV）的雄性大鼠表现出异常高的药物摄入量；然而，影响这种行为的因素（例如强化历史和性别）尚不清楚。
描述 MDPV 在雌性大鼠中的强化效力和效果，以确定（1）是否也有一小部分雌性大鼠发展出高水平的 MDPV 自我给药（即高反应表型），以及（2）高反应表型受各种强化历史（即可卡因或食物的反应）影响的程度。
最初，雌性 Sprague Dawley 大鼠根据固定比率（FR）1 和 FR5 强化程序，对 MDPV（0.032mg/kg/ 输注）、可卡因（0.32mg/kg/ 输注）或食物（45mg 谷物丸）进行反应。在 20 个疗程后，可卡因和食物历史的大鼠在另外 20 个疗程中对 MDPV 进行反应。在 FR5 和递增比率（PR）强化程序下生成 MDPV 的剂量反应曲线。
一小部分对 MDPV 进行反应的大鼠发展出高水平的 MDPV 摄入量。可卡因的反应历史，但不是食物的反应历史，抑制了高水平 MDPV 摄入量的发展。当 MDPV 根据 FR5 而不是 PR 强化程序可用时，观察到自我给药水平的个体差异很大。
MDPV 作为一种强大的强化物在雌性大鼠中起作用，正如之前在雄性大鼠中报道的那样。当 MDPV 根据 FR5 而不是 PR 强化程序可用时，观察到自我给药水平的个体差异很大。
