Schizophrenia-like behavior is not altered by melatonin supplementation in rodents

Abstract An emerging area in schizophrenia research focuses on the impact of immunomodulatory drugs such as melatonin, which have played important roles in many biological systems and functions, and appears to be promising. The objective was to evaluate the effect of melatonin on behavioral parameters in an animal model of schizophrenia. For this, Wistar rats were divided and used in two different protocols. In the prevention protocol, the animals received 1 or 10mg/kg of melatonin or water for 14 days, and between the 8th and 14th day they received ketamine or saline. In the reversal protocol, the opposite occurred. On the 14th day, the animals underwent behavioral tests: locomotor activity and prepulse inhibition task. In both protocols, the results revealed that ketamine had effects on locomotor activity and prepulse inhibition, confirming the validity of ketamine construction as a good animal model of schizophrenia. However, at least at the doses used, melatonin was not able to reverse/prevent ketamine damage. More studies are necessary to evaluate the role of melatonin as an adjuvant treatment in psychiatric disorders.

摘要
精神分裂症研究领域的新兴方向聚焦于褪黑素（melatonin）等免疫调节药物的作用效果。褪黑素在诸多生物系统与生理功能中发挥着重要作用，且展现出良好的应用前景。本研究旨在评估褪黑素对精神分裂症动物模型行为学参数的影响。为此，将Wistar大鼠分组，并采用两种不同的实验方案：
在预防方案中，大鼠每日分别接受1mg/kg、10mg/kg剂量的褪黑素或纯水，持续14天；于第8天至第14天期间，额外给予氯胺酮（ketamine）或生理盐水处理。逆转方案的处理流程则恰好相反。
于第14天，对所有大鼠开展行为学测试，包括自主活动度实验与前脉冲抑制（prepulse inhibition）任务。两种方案的实验结果均显示，氯胺酮可对大鼠的自主活动度与前脉冲抑制产生影响，证实了氯胺酮造模作为精神分裂症动物模型的有效性。但就本研究使用的剂量而言，褪黑素未能逆转或阻断氯胺酮诱导的行为损伤。未来仍需开展更多研究，以评估褪黑素作为精神疾病辅助治疗手段的应用价值。