Mistlberger R E, Mumby D G
Department of Psychology, Simon Fraser University, Burnaby, BC, Canada.
Behav Brain Res. 1992 Apr 10;47(2):159-68. doi: 10.1016/s0166-4328(05)80122-6.
Rats behaviorally anticipate a fixed, daily opportunity to feed by entrainment of circadian oscillators that are physically separate from the light-entrainable circadian pacemaker that has been localized to the suprachiasmatic nucleus. Neural substrates mediating food-entrained rhythms are unknown. A variety of anatomical and functional observations suggest possible involvement of the limbic system and its dopaminergic component in the regulation of these rhythms. To test this hypothesis, the activity rhythms of rats bearing large, combined ablations of the hippocampus and amygdala or nucleus accumbens and medical forebrain anterior to the thalamus were examined under ad-lib feeding, 2 h daily feeding, and total food deprivation conditions. Some hippocampal-ablated rats showed alterations of free-running rhythms under ad-lib feeding, but none of the ablations impaired the rats' ability to anticipate daily feeding, or 'remember' the phase of feeding time during subsequent food deprivation. Additional groups of intact rats were treated with the dopamine antagonist haloperidol (0.3 mg/kg or 2.0 mg/kg) 30 min prior to daily feeding, but this also did not prevent the emergence of food-entrained rhythms. The limbic and dopamine systems do not appear to play a necessary role in the generation or entrainment of food-anticipatory circadian rhythms.
大鼠通过与位于视交叉上核的可被光调节的昼夜节律起搏器在物理上分离的昼夜节律振荡器的同步，在行为上预期每天有固定的进食机会。介导食物同步节律的神经基质尚不清楚。各种解剖学和功能观察表明，边缘系统及其多巴胺能成分可能参与这些节律的调节。为了验证这一假设，在自由进食、每天2小时进食和完全禁食条件下，检查了海马体和杏仁核或伏隔核以及丘脑前方的内侧前脑进行大面积联合切除的大鼠的活动节律。一些海马体切除的大鼠在自由进食条件下表现出自由活动节律的改变，但没有一种切除损害了大鼠预期每日进食的能力，或在随后的禁食期间“记住”进食时间的阶段。另外几组完整的大鼠在每天进食前30分钟用多巴胺拮抗剂氟哌啶醇（0.3毫克/千克或2.0毫克/千克）进行处理，但这也没有阻止食物同步节律的出现。边缘系统和多巴胺系统似乎在食物预期昼夜节律的产生或同步中不起必要作用。
