Laboratori de Neuroanatomia Funcional Comparada, Department of Biologia Funcional i Antropologia Física, Facultat de Ciències Biològiques, Universitat de València. C. Dr. Moliner, 50, 46100 Burjassot, València, Spain.
Behav Brain Res. 2012 Jan 15;226(2):538-47. doi: 10.1016/j.bbr.2011.10.013. Epub 2011 Oct 15.
Male sexual pheromones are rewarding stimuli for female mice, able to induce conditioned place preference. To test whether processing these natural reinforcing stimuli depends on the dopaminergic innervation of the nucleus accumbens, as for other natural rewards, we compare the effects of specific lesions of the dopaminergic innervation of the medial shell of the nucleus accumbens on two different appetitive behaviours, 'pheromone seeking' and sucrose preferential intake. Female mice, with no previous experience with either adult male chemical stimuli or with sucrose, received injections of 6-hydroxydopamine (or vehicle) in the medial shell of the accumbens. Then, we analyzed their preference for male soiled-bedding and their preferential intake of a sucrose solution, with particular emphasis on the dynamics of acquisition of both natural rewards. The results indicate that both lesioned and sham animals showed similar preference for male sexual pheromones, which was constant along the test (linear dynamics). In contrast, lesioned animals differed from sham operated mice in the dynamics of sucrose consumption in their first test of sucrose preference. Sham animals showed an initial sucrose preference followed by preference for water, which can be interpreted as sucrose neophobia. Lesioned animals showed no preference at the beginning of the test, and a delayed sucrose preference appeared followed by a delayed neophobia. The next day, during a second sucrose-preference test, both groups displayed comparable and sustained preferential sucrose intake. Therefore, dopamine in the medial shell of the nucleus accumbens has a different role on the reward of sexual pheromones and sucrose.
雄性性信息素是雌性小鼠的奖赏性刺激物，能够诱导条件性位置偏好。为了测试处理这些天然强化刺激是否依赖于伏隔核内侧壳的多巴胺能神经支配，就像其他天然奖赏一样，我们比较了内侧壳的多巴胺能神经支配的特定损伤对两种不同的食欲行为（“信息素寻求”和蔗糖偏好摄入）的影响。没有接触过成年雄性化学刺激或蔗糖的雌性小鼠接受了内侧壳的 6-羟多巴胺（或载体）注射。然后，我们分析了它们对雄性污染垫的偏好和对蔗糖溶液的偏好，特别强调了两种天然奖赏的获取动态。结果表明，受损和假手术动物对雄性性信息素表现出相似的偏好，这种偏好沿测试保持不变（线性动态）。相比之下，受损动物在第一次蔗糖偏好测试中对蔗糖消耗的动力学与假手术组的动物不同。假手术组的动物表现出对蔗糖的初始偏好，然后对水的偏好，这可以解释为蔗糖厌恶。受损动物在测试开始时没有偏好，随后出现延迟的蔗糖偏好，然后是延迟的厌恶。第二天，在第二次蔗糖偏好测试中，两组动物都表现出类似的、持续的蔗糖偏好摄入。因此，伏隔核内侧壳中的多巴胺在性信息素和蔗糖的奖赏中具有不同的作用。
