CNS MELATONIN TARGET SITES--CONTROL OF SEASONAL CYCLES

本研究的目标是确定中枢神经系统的目标部位 负责光周期控制的褪黑素(MEL) 季节性能量平衡和生殖状态。环境问题 在许多物种中，这些反应的信号是 白天，其神经内分泌转导是松果体和 它的荷尔蒙，褪黑素(MEL)。梅尔只在晚上和在这个 分泌物的持续时间决定了白天的长度。因此，“冬天般的” 短天数(SD)和像夏天一样的长天数(LD)与长相关 和短持续时间MEL信号。西伯利亚仓鼠将成为 研究表明，这一物种的能量呈现出戏剧性的季节性变化 光周期变化后的调控。特定目标(SA)1： 破坏假定的CNS MEL目标部位是否会阻止接收 关于梅尔信号的？SA-1的目的是识别涉及的大脑部位 在通过以下处理接收/表达MEL信号时 破坏的范围和类型不断缩小 成年雄性松果体摘除(PINX)动物的靶点挑战 利用定时输注范例(TIP)传递外源MEL信号 通过S.C.管理路线。将接收到的大脑区域 病变显示MEL结合和/或参与整合 代谢和生殖反应。一系列病变类型将 制作：直流电、微刀切割和神经毒素破坏细胞 通道的小体和纤维，只有通道的纤维，只有细胞 分别是身体。每个人都将进行两组实验 第一，SD-型抑制性MEL的作用 新陈代谢和生殖反应的信号将通过给予 LD饲养的Pinx仓鼠，每天有或没有皮损，Mel或生理盐水 通过TIP输液，而在第二种情况下，LD的效果- 这些反应上的类型刺激MEL信号将通过以下方式进行测试 光退SD-有或没有病变的Pinx仓鼠MEL 通过尖端发出信号。病变诱导的两组预期的阻断 每个实验中的响应将指示一个位于 对MEL的接收/表达负责最少 信号。SA 2：刺激假定的MEL靶点是否会模仿 光周期变化诱导的反应？SA 2的目的是 刺激Pinx LD饲养的仓鼠的SD类型的反应，或返回 SD饲养、光退化Pinx仓鼠的LD-型反应 脑内注射MEL显示MEL结合和 在上述实验中，病变阻断了MEL信号的影响。 例如，如果病变阻断了MEL诱导的SD类型的反应，那么只有 长时间脑内注射MEL将引起这些反应； 在同一地点进行的其他类型的输液则不会。反之亦然 被发现是因为大脑部位的病变阻碍了向LD型的回归 SD饲养的光退化仓鼠的LD MEL信号状态。 这些发现应该有助于确定自然发生的变化是如何 环境会影响能量平衡和繁殖。

The goal of this research is to identify the CNS target sites of melatonin (MEL) that are responsible for the photoperiodic control of seasonal energy balance and reproductive status. The environmental signal for these responses in many species is the change in the daylength, the neuroendocrine transducer of which is the pineal gland and its hormone, melatonin (MEL). MEL only is secreted at night and in this way the duration of secretion encodes the daylength. Thus, 'winter-like' short days (SD) and 'summer-like' long days (LD) are associated with long and short duration MEL signals, respectively. Siberian hamsters will be studied, a species that exhibits dramatic seasonal changes in energy regulation following changes in the photoperiod. Specific Aims (SA) 1: Does destruction of the putative CNS MEL target sites block the reception of MEL signals? the purpose of SA 1 is to identify brain sites involved in the reception/expression of the MEL signals through a process of successive narrowing of the extent and type of destruction of the targeted sites in adult male pinealectomized (PINX) animals challenged with the timed infusion paradigm (TIP) to deliver exogenous MEL signals via the s.c. route of administration. The brain sites that will receive lesions show MEL binding and/or are involved in the integration of metabolic and reproductive responses. A sequence of lesion types will be made: direct current, microknife cut and neurotoxins to destroy cell bodies and fibers of passage, only fibers of passage, and only cell bodies, respectively. Two sets of experiments will be conducted for each brain site in SA 1. In the first, the effects of SD-type inhibitory MEL signals on metabolic and reproductive responses will be tested by giving LD-housed, PINX hamster with or without lesions daily MEL or saline vehicle infusions via the TIP, whereas in the second, the effects of LD- type stimulatory MEL signals on these responses will be tested by giving photoregressed SD-housed, PINX hamsters with or without lesions MEL signals via the TIP. Lesion-induced blockade of either expected set of responses in each experiment will be indicative of a site that is at least responsible partially for the reception/expression of the MEL signal. SA 2: Does stimulation of putative MEL target sites mimic photoperiod change-induced responses? The purpose of SA 2 is to stimulate SD-type responses in PINX LD-housed hamsters, or the return to LD-type responses in SD-housed, photoregressed PINX hamsters via intracerebral MEL infusions at brain sites that show MEL binding and where lesions block the effects of MEL signals in the above experiments. For example, if a lesion blocks MEL-induced, SD-type responses, then only long duration intracerebral MEL infusions will elicit these responses; other types of infusions at the same site will not. The converse should be found for a brain site where lesions block the return to LD-type status by LD MEL signals in SD-housed photoregressed hamsters. These findings should help determine how naturally-occurring changes in the environment can affect energy balance and reproduction.