Moss I R, Inman J G, Slaughter C A
Department of Pediatrics, University of Texas, Southwestern Medical Center, Dallas.
Am J Physiol. 1989 Feb;256(2 Pt 2):R429-34. doi: 10.1152/ajpregu.1989.256.2.R429.
We have measured levels of beta-lipotropin, beta-endorphin, and N-acetyl-beta-endorphin in the plasma, cerebrospinal fluid (CSF), and caudal medullary brain containing the respiratory-related portion of the nucleus tractus solitarius (NTS) of 2.5 +/- 1.0- (SD) and 38.2 +/- 3.7-day-old naive uninstrumented piglets. Time of day, ambient atmosphere, temperature, handling, sound, light, and nutritional status were kept constant. Experimental procedure included decapitation and rapid collection, processing, and freezing of tissues until analysis by radioimmunoassay. Young, compared with older piglets, have higher measured levels of beta-lipotropin in the plasma and CSF and of N-acetyl-beta-endorphin in all three body compartments. Although measured levels of beta-endorphin-like immunoreactivity are also higher in the plasma and CSF of the young group, the calculated level of beta-endorphin is higher only in the CSF. In the NTS, both the measured and calculated active endorphin appear higher in the older group, but this difference is not significant. Excess beta-endorphin in the CSF of neonates may explain the relative immaturity of their respiratory functions at birth.
我们测定了2.5±1.0（标准差）日龄和38.2±3.7日龄未经插管的新生仔猪血浆、脑脊液（CSF）以及含有孤束核（NTS）呼吸相关部分的延髓尾部脑组织中β-促脂素、β-内啡肽和N-乙酰-β-内啡肽的水平。每日时间、环境大气、温度、处理方式、声音、光线和营养状况均保持恒定。实验步骤包括断头以及快速采集、处理和冷冻组织，直至通过放射免疫测定法进行分析。与年长仔猪相比，年幼仔猪血浆和脑脊液中β-促脂素的测定水平以及所有三个身体腔室中N-乙酰-β-内啡肽的测定水平更高。尽管年轻组血浆和脑脊液中β-内啡肽样免疫反应性的测定水平也更高，但β-内啡肽的计算水平仅在脑脊液中更高。在NTS中，年长组中测定的和计算的活性内啡肽似乎都更高，但这种差异不显著。新生儿脑脊液中过量的β-内啡肽可能解释了他们出生时呼吸功能相对不成熟的原因。
