Department of Animals in Science and Society, Division of Behavioural Neuroscience, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
Department of Science, Section of Biomedical Sciences and Technologies, University "Roma Tre", Rome, Italy.
Neuropharmacology. 2019 Nov 15;159:107332. doi: 10.1016/j.neuropharm.2018.09.007. Epub 2018 Sep 13.
Social play behaviour is a vigorous form of social interaction abundant during the juvenile and adolescent phases of life in many mammalian species, including rats and humans. Social play is thought to be important for social, emotional and cognitive development. Being a rewarding activity, the expression of social play depends on its pleasurable and motivational properties. Since opioids have been widely implicated in reward processes, in the present study we investigated the role of opioids in the pleasurable and motivational properties of social play behaviour in rats. To assess social play motivation, an operant conditioning setup was used in which rats responded for social play under a progressive ratio schedule of reinforcement. Treatment with the opioid receptor agonist morphine reduced responding for social play at the highest dose tested, likely due to its rate-limiting effects. Morphine treatment increased the expression of social play behaviour during reinforced periods. The acquisition of social play-induced conditioned place preference (CPP) in a subeffective conditioning protocol was enhanced by treatment with morphine. Morphine treatment alone also induced CPP. In contrast, antagonizing opioid receptors with naloxone reduced responding for social play, the expression of social play and blocked the development of social play-induced CPP. These data implicate opioid neurotransmission in both the pleasurable and the motivational aspects of social play behaviour in rats. This article is part of the Special Issue entitled 'The neuropharmacology of social behavior: from bench to bedside'.
社会玩耍行为是一种在许多哺乳动物物种的幼年期和青少年期都非常丰富的活跃的社交互动形式，包括老鼠和人类。社会玩耍被认为对社交、情感和认知发展很重要。作为一种有益的活动，社会玩耍的表达取决于其愉悦和激励特性。由于阿片类物质广泛参与了奖励过程，因此在本研究中，我们调查了阿片类物质在老鼠社会玩耍行为的愉悦和激励特性中的作用。为了评估社会玩耍的动机，我们使用了一种操作性条件反射装置，其中老鼠根据递增比率强化时间表来回应社会玩耍。阿片受体激动剂吗啡的治疗降低了在最高剂量测试下的社会玩耍反应，这可能是由于其限速作用。吗啡治疗增加了强化期间社会玩耍行为的表达。在亚效条件作用方案中，用吗啡处理增强了社会玩耍诱导的条件位置偏好（CPP）的获得。吗啡单独治疗也诱导了 CPP。相比之下，用纳洛酮拮抗阿片受体减少了对社会玩耍的反应、社会玩耍的表达并阻止了社会玩耍诱导的 CPP 的发展。这些数据表明阿片类神经递质在老鼠的社会玩耍行为的愉悦和激励方面都有涉及。本文是题为“社会行为的神经药理学：从基础到临床”的特刊的一部分。
