Dopamine (DA), serotonin (5-hydroxytryptamine, 5-HT), and endocannabinoids (ECs) are key neuromodulators involved in many aspects of motivated behavior, including reward processing, reinforcement learning, and behavioral flexibility. Among the longstanding views about possible relationships between these neuromodulators is the idea of DA and 5-HT acting as opponents. This view has been challenged by emerging evidence that 5-HT supports reward seeking via activation of DA neurons in the ventral tegmental area. Adding an extra layer of complexity to these interactions, the endocannabinoid system is uniquely placed to influence dopaminergic and serotonergic neurotransmission. In this review we discuss how these three neuromodulatory systems interact at the cellular and circuit levels. Technological advances that facilitate precise identification and control of genetically targeted neuronal populations will help to achieve a better understanding of the complex relationship between these essential systems, and the potential relevance for motivated behavior.

多巴胺 (DA)、5-羟色胺 (5-羟色胺、5-HT) 和内源性大麻素 (EC) 是参与动机行为许多方面的关键神经调节剂，包括奖励处理、强化学习和行为灵活性。关于这些神经调节剂之间可能的关系的长期观点之一是 DA 和 5-HT 作为对手的想法。这一观点受到新证据的挑战，这些证据表明 5-HT 通过激活腹侧被盖区域的 DA 神经元来支持寻求奖励。为这些相互作用增加了一层额外的复杂性，内源性大麻素系统具有独特的影响多巴胺能和血清素能神经传递的位置。在这篇综述中，我们讨论了这三种神经调节系统如何在细胞和电路水平上相互作用。