摘要
应用细胞外引导的电生理手段，在家兔隔区记录到两类热敏单位：一类热敏单位的放电频率对脑温反应的阈但是３８℃左右；另一类直到脑温升高至４０℃左右时才表现出温度敏感性。在此基础上，观察了致热原，及α－促黑素（α－ＭＳＨ）对致热原作用下的隔区热敏神经元放电活动的影响。结果，小剂量致热原只能抑制前一类神经元的电活动，较大剂量的致辞热原则对两类神经元均显示抑频效应；α－促黑素则不同程度地反转致热原对两类神经元的抑制性影响。本文结果支持这样一种设想：隔区神经元的作用不是直接发动体温调节反应，而是为视前区─—下丘脑前部（ＰＯ／ＡＨ），这一重要的体温调节中枢提供参照信息；α－促黑素很可能是通过改变隔区的参照信息而实现其解热效应的。
o investigate a
possible central mechanism of antipyretic effects of α-melanocyte
stimulating hor-mone(α-MSH),we recorded the single unit activity of
warm-sensitive neurons in the septum of rabbitsusing micro-electrode
technique.Two kind of units, Type-Ⅰand Type-Ⅱ neurons, were
observed with38℃ response threshold of the former and 40℃ threshold
of the latter. Since a febrile condition is nec-essary to demonstrate
the antipyretic action, the effect of endotoxin of E.coli on the
activity of neuronswas examined first. This agent was found to
depress only the activity of Type-Ⅰunits when smallerdose(0.005 μ
g/kg) was used, and to suppress those of both Type-Ⅰand Type-Ⅱ
units when biggerdose(0.015 μg/kg)was used.The introvenous
administration of α-MSH(2 μg/kg)after maximal neu-ronal suppression
of two type of units resulted in return of thermal responsiveness
towards prepyrogenlevel within 12 min to 25 min. Our results
suggested that the septum may not be the primary centralsite of
antipyretic action of α-MSH, but play a mediate role.
出处
《中国医科大学学报》
CAS
CSCD
1995年第6期551-556,共6页
Journal of China Medical University
基金
国家自然科学基金资助课题
