Departamento de Neurociencia y Ciencias de la Salud, Universidad de Almería, Carretera de Sacramento s/n, La Cañada de San Urbano, 04120 Almería, Spain.
Psychopharmacology (Berl). 2012 Jan;219(2):661-72. doi: 10.1007/s00213-011-2575-y. Epub 2011 Nov 24.
Schedule-induced polydipsia (SIP), characterized by the development of excessive drinking under intermittent food reinforcement schedules, has been proposed as a model for obsessive-compulsive disorder, schizophrenia and drug abuse.
The purpose of this study is to investigate if individual differences in SIP reflect psychopathological behavioural traits related to lack of inhibitory control and reactivity to novelty, and if these differences have neurochemical correlates.
Outbred Wistar rats were selected for being either high (HD) or low (LD) drinkers according to their SIP behaviour. We tested locomotor reactivity to a novel environment and inhibitory control on the five-choice serial reaction time task (5-CSRTT), under baseline vs. extinction conditions and following challenge with D: -amphetamine (saline, 0.5 or 1 mg/kg). Post-mortem analyses of the monoaminergic levels in different brain regions were also analysed.
Compared to LD animals, HD rats exhibiting SIP acquisition showed no differences in spontaneous locomotor reactivity to novelty. On the 5-CSRTT, HD rats showed a greater increase in perseverative responses under extinction, a trend towards elevated premature responses on baseline, and a significantly greater elevation of premature responses to D: -amphetamine 0.5 mg/kg. The HD animals also exhibited increased serotonin activity in the amygdala, and correlational analyses between the rate of drinking on SIP and monoamine levels also revealed altered dopaminergic mesolimbic function.
These findings show that HD rats selected by SIP exhibit compulsive and impulsive behaviour based on measures of performance on the five-choice serial reaction time task and associated with changes in monoaminergic systems in limbic-striatal circuitry.
间歇性食物强化方案引起的多饮（SIP），表现为在间歇性食物强化方案下发展出过度饮水，被提出作为强迫症、精神分裂症和药物滥用的模型。
本研究的目的是调查 SIP 中的个体差异是否反映了与缺乏抑制控制和对新奇事物反应性相关的心理病理行为特征，以及这些差异是否具有神经化学相关性。
根据 SIP 行为，选择野生型 Wistar 大鼠作为高（HD）或低（LD）饮水者。我们测试了在基线与消退条件下，以及在 D：-苯丙胺（盐水、0.5 或 1mg/kg）挑战下，对新环境的运动反应性和对 5-选择连续反应时间任务（5-CSRTT）的抑制控制。还分析了不同脑区单胺能水平的死后分析。
与 LD 动物相比，表现出 SIP 习得的 HD 大鼠在对新奇事物的自发运动反应性方面没有差异。在 5-CSRTT 上，HD 大鼠在消退时表现出更多的持续反应增加，在基线时表现出提前反应的趋势增加，对 D：-苯丙胺 0.5mg/kg 的提前反应明显增加。HD 动物的杏仁核中也表现出更高的血清素活性，并且 SIP 中饮水率与单胺水平之间的相关分析也显示出边缘纹状体回路中多巴胺能中脑边缘功能的改变。
这些发现表明，通过 5-选择连续反应时间任务的表现和相关的边缘纹状体回路中单胺能系统的变化来选择的 SIP 大鼠表现出强迫和冲动行为。
