Cannabinoid (CB) receptors are widespread in the nervous system and influence a variety of behaviors. Weakly electric fish have been a useful model system in the study of the neural basis of behavior, but we know nothing of the role played by the CB system. Here, we determine the overall behavioral effect of a nonselective CB receptor agonist, namely Δ9-tetrahydrocannabinol (THC), in the weakly electric fish Apte-ronotus leptorhynchus. Using various behavioral paradigms involving social stimuli, we show that THC decreases locomotor behavior, as in many species, and influences communication and social behavior. Across the different experiments, we found that the propensity to emit communication signals (chirps) and seek social interactions was affected in a context-dependent manner. We explicitly tested this hypothesis by comparing the behavioral effects of THC injection in fish placed in a novel versus a familiar social and physical environment. THC-injected fish were less likely to chirp than control fish in familiar situations but not in novel ones. The tendency to be in close proximity to other fish was affected only in novel environments, with control fish clustering more than THC-injected ones. By identifying behaviors affected by CB agonists, our study can guide further comparative and neurophysiological studies of the role of the CB system using a weakly electric fish as a model.

中文翻译：

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弱电鱼中Δ9-四氢大麻酚的选择性和情境相关的社会和行为影响。

大麻素（CB）受体广泛分布于神经系统中，并影响多种行为。弱电鱼在研究行为的神经基础方面一直是有用的模型系统，但我们对CB系统所起的作用一无所知。在这里，我们确定了非选择性CB受体激动剂，即Δ9-四氢大麻酚（THC）在弱电鱼Apte-ronotus leptorhynchus中的整体行为效果。使用涉及社会刺激的各种行为范例，我们表明THC会像许多物种一样减少运动行为，并影响交流和社会行为。在不同的实验中，我们发现发出通讯信号（chi）和寻求社交互动的倾向以上下文相关的方式受到影响。我们通过比较THC注射在放置在新型鱼与熟悉的社会和自然环境中的鱼的行为影响中，明确检验了这一假设。在熟悉的情况下，注入THC的鱼比对照鱼to的可能性较小，但在新颖的情况下则不会。靠近其他鱼类的趋势仅在新颖的环境中受到影响，对照鱼类的聚集程度大于注入THC的鱼类。通过确定受CB激动剂影响的行为，我们的研究可以使用弱电鱼作为模型来指导CB系统作用的进一步比较和神经生理学研究。靠近其他鱼类的趋势仅在新颖的环境中受到影响，对照鱼类的聚集程度大于注入THC的鱼类。通过确定受CB激动剂影响的行为，我们的研究可以使用弱电鱼作为模型来指导CB系统作用的进一步比较和神经生理学研究。靠近其他鱼类的趋势仅在新颖的环境中受到影响，对照鱼类的聚集程度大于注入THC的鱼类。通过确定受CB激动剂影响的行为，我们的研究可以使用弱电鱼作为模型来指导CB系统作用的进一步比较和神经生理学研究。