Department of Psychology, Davidson College, Davidson, NC 28035, USA.
Department of Psychology, Davidson College, Davidson, NC 28035, USA.
Behav Brain Res. 2021 Jul 9;409:113329. doi: 10.1016/j.bbr.2021.113329. Epub 2021 Apr 29.
Heroin intake decreases during the proestrus phase of the estrous cycle in female, Long-Evans rats. The purpose of this study was to (1) determine if proestrus-associated decreases in heroin intake extend across rat strains and (2) determine if proestrus-associated decreases in responding extend to a nondrug reinforcer. Female rats were implanted with intravenous catheters and trained to self-administer heroin. Estrous cycle was tracked daily for the duration of the study. During testing, Lewis, Sprague Dawley, and Long-Evans rats self-administered low (0.0025 mg/kg) and high (0.0075 mg /kg) doses of heroin and then self-administered sugar on fixed ratio (FR1) schedules of reinforcement. Heroin intake decreased significantly during proestrus in all three rat strains under at least one dose condition; however, sugar intake did not decrease during proestrus in any strain. These data suggest that responding maintained by heroin, but not a nondrug reinforcer, significantly decreases during proestrus in female rats and that these effects are consistent across rat strain.
在雌性长爪沙鼠动情周期的发情前期，海洛因的摄入量会减少。本研究的目的是：(1) 确定发情前期相关的海洛因摄入量减少是否会扩展到不同的大鼠品系；(2) 确定发情前期相关的反应减少是否会扩展到非药物强化物。雌性大鼠被植入静脉导管，并接受海洛因自我给药训练。在研究期间，每天跟踪发情周期。在测试期间，Lewis、Sprague Dawley 和 Long-Evans 大鼠在至少一种剂量条件下自我给予低 (0.0025mg/kg) 和高 (0.0075mg/kg) 剂量的海洛因，然后在固定比率 (FR1) 强化方案下自我给予糖。在至少一种剂量条件下，所有三种大鼠品系在发情前期海洛因的摄入量均显著减少；然而，在任何一种大鼠品系中，糖的摄入量在发情前期均未减少。这些数据表明，在雌性大鼠中，海洛因维持的反应，但不是非药物强化物，在发情前期显著减少，并且这些效应在大鼠品系之间是一致的。
