Cannabinoid receptor type 1 (CB1R) is the most abundant cannabinoid receptor in central nervous system. Clinical studies and animal models have shown that the attenuation of endocannabinoid system signaling correlates with the development of psychiatric disorders such as anxiety, depression and schizophrenia. In the present work, multiple behavioral tests were performed to evaluate behaviors related to anxiety and depression in CB1R^+/- and CB1R^-/-. CB1R^+/- mice had anxiety-related behavior similar to wild type (CB1R^+/+) mice, whereas CB1R^-/- mice displayed an anxious-like phenotype, which indicates that lower expression of CB1R is sufficient to maintain the neural circuits modulating anxiety. In addition, CB1R^-/- mice exhibited alterations in risk assessment and less exploration, locomotion, grooming, body weight and appetite. These phenotypic characteristics observed in CB1R^-/- mice could be associated with symptoms observed in human psychiatric disorders such as depression. A better knowledge of the neuromodulatory role of CB1R may contribute to understand scope and limitations of the development of medical treatments.

1 型大麻素受体 (CB1R) 是中枢神经系统中最丰富的大麻素受体。临床研究和动物模型表明，内源性大麻素系统信号减弱与焦虑、抑郁和精神分裂症等精神疾病的发展相关。在目前的工作中，进行了多项行为测试，以评估 CB1R ^+/-和 CB1R ^{-/- 中}与焦虑和抑郁相关的行为。CB1R ^+/-小鼠的焦虑相关行为类似于野生型 (CB1R ^+/+ ) 小鼠，而 CB1R ^-/-小鼠表现出类似焦虑的表型，这表明 CB1R 的较低表达足以维持调节焦虑的神经回路。此外，CB1R ^-/-小鼠在风险评估和探索、运动、梳理、体重和食欲方面表现出改变。在 CB1R ^-/-小鼠中观察到的这些表型特征可能与在人类精神疾病（如抑郁症）中观察到的症状有关。更好地了解 CB1R 的神经调节作用可能有助于了解医学治疗发展的范围和局限性。