Studies on Brain Histamine Neurons Using Gene-Targetted Mice

大脑中的组胺能神经元系统与大脑的各种功能有关，引起了许多神经科学家的兴趣。最近，研究人员培育出了H1和H2受体基因和组氨酸脱羧酶（HDC，一种组胺形成酶）基因缺失的小鼠。在这项研究中，组胺在睡眠-觉醒昼夜节律、自发行为、焦虑、学习记忆和抽搐等方面的功能进行了国际合作。到目前为止，HDC- ko小鼠虽然没有HDC活动，但组胺含量却很少，这表明组胺还有其他来源。我们推测组胺是从肠道吸收的，因为给KO小鼠喂食低组胺含量的食物会降低组织中的组胺水平。为了方便可靠地比较野生小鼠和KO小鼠的数据，我们生产了129只近交系小鼠。由于上述两个原因，老鼠的分发被推迟了，但它们现在正在被送到合作者那里。2000年11月22日至25日，国际仙台组胺研讨会在仙台召开，本基金所有成员参加了研讨会并进行了交流。

The histaminergic neuron system in the brain attracts interests of many neuroscientists, because it is related to various brain functions. Recently, mice with genes for H1 and H2 receptors and histidine decarboxylase (HDC, a histamine-forming enzyme) knocked out have been developed. In this research, international collaboration of functions of histamime in sleep-awakeness circadian rhythm, spontaneous behavior, anxiety, learning-memory and convulsions have been carried out. So far, it turned out that HDC-KO mice have a little level of histamine in spite of no HDC activity, suggesting that there is another source of histamine. We speculate that histamine is absorbed from the gut, because feeding the KO mice with a diet of low histamine content decreased the histamine levels in tissues. For easy and reliable comparison of data obtained in wild and KO mice, the inbred 129 mice were produced. By the two reqasons mentioned above, the distribution of the mice was delayed but they are now being sent to the collaborators. From November 22 to 25, 2000, International Sendai Histamine Symposium was held in Sendai, and all the members of this grant attended the Sympo sium and exchanged informations and ideas.