Oxytocin potently reduces food intake and is a potential target system for obesity treatment. A better understanding of the behavioral and neurobiological mechanisms mediating oxytocin's anorexigenic effects may guide more effective obesity pharmacotherapy development. The present study examined the effects of central (lateral intracerebroventricular [ICV]) administration of oxytocin in rats on motivated responding for palatable food. Various conditioning procedures were employed to measure distinct appetitive behavioral domains, including food seeking in the absence of consumption (conditioned place preference expression), impulsive responding for food (differential reinforcement of low rates of responding), effort-based appetitive decision making (high-effort palatable vs. low-effort bland food), and sucrose reward value encoding following a motivational shift (incentive learning). Results reveal that ICV oxytocin potently reduces food-seeking behavior, impulsivity, and effort-based palatable food choice, yet does not influence encoding of sucrose reward value in the incentive learning task. To investigate a potential neurobiological mechanism mediating these behavioral outcomes, we utilized in vivo fiber photometry in ventral tegmental area (VTA) dopamine neurons to examine oxytocin's effect on phasic dopamine neuron responses to sucrose-predictive Pavlovian cues. Results reveal that ICV oxytocin significantly reduced food cue-evoked dopamine neuron activity. Collectively, these data reveal that central oxytocin signaling inhibits various obesity-relevant conditioned appetitive behaviors, potentially via reductions in food cue-driven phasic dopamine neural responses in the VTA.

催产素可有效减少食物摄入量，是治疗肥胖症的潜在目标系统。更好地了解介导催产素的厌食作用的行为和神经生物学机制可能会指导更有效的肥胖药物治疗开发。本研究检查了大鼠中枢（侧脑室 [ICV]）催产素对可口食物的主动反应的影响。各种调节程序被用来测量不同的食欲行为领域，包括在没有消费的情况下寻求食物（条件性位置偏好表达），对食物的冲动反应（低反应率的差异强化），基于努力的食欲决策（高-努力可口与省力平淡的食物），和蔗糖奖励值编码后的动机转变（激励学习）。结果表明，ICV 催产素有效地减少了觅食行为、冲动性和基于努力的可口食物选择，但不影响激励学习任务中蔗糖奖励值的编码。为了研究调节这些行为结果的潜在神经生物学机制，我们在腹侧被盖区 (VTA) 多巴胺神经元中利用体内纤维光度法来检查催产素对阶段性多巴胺神经元对蔗糖预测巴甫洛夫线索的反应的影响。结果表明，ICV 催产素显着降低了食物线索诱发的多巴胺神经元活动。总的来说，这些数据表明中枢催产素信号抑制了各种与肥胖相关的条件性食欲行为，