PubMed · 3719215
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D S Sheriff. 1986. Embryo research.. https://pubmed.ncbi.nlm.nih.gov/3719215/
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The presented study investigates the time-dependent release of PGI2 and TXA2 by isolated human umbilical veins in vitro using the radioimmunoassay for measurement. After changing the nutritional fluid--Krebs-Henseleit solution at pH 7.4, 37 degrees C, 95% O2/5% CO2--the release graph oscillates. These oscillations with time were verified by variance analysis and are very similar for both substances. This indicates one or several negative feedback mechanisms acting on the common path of synthesis from the membrane-bound phospholipids to PGH2, which are effective in the regulation of eicosanoid biosynthesis in vitro. A mathematical function describing the observed PGI2 and TXA2 synthesis is communicated.
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An immunohistochemical study of spinal cord, dorsal root and sympathetic ganglia of human embryos and fetuses demonstrated that neuropeptide Y and its C-flanking peptide could be detected in seven-week-old embryos but were absent or difficult to demonstrate after the 17th week of gestation. The peptides were found in several structures of the spinal cord, e.g. fibres in the dorsal portion of the lateral funiculus, cell bodies and fibres in the dorsal horn, and motoneurons, and also in numerous primary sensory neurons of dorsal root ganglia. They were also present in sympathetic neurons and since these are the only structures expressing neuropeptide Y and its C-flanking peptide in the adult, it must be concluded that their presence in other neurons is a transient developmental feature. To assist in understanding the relationship of these transient structures with other spinal and sensory neurons, a comparison was made with other neuronal structures showing immunoreactivity for two general neuronal markers, neurofilaments and protein gene product 9.5, and two neuropeptides present in primary sensory afferents, somatostatin and substance P. In the dorsal root ganglia, numerous neuropeptide Y- and C-flanking peptide-immunoreactive neurons were observed before substance P- or somatostatin-immunoreactive cells could be detected. Therefore, neuropeptide Y and its C-flanking peptide could represent a primitive peptidergic system appearing before primary sensory neurons express their characteristic adult phenotype. The fibres of the lateral funiculus showing immunoreactivity for neuropeptide Y and its C-flanking peptide were longitudinally orientated and could be detected at all cephalocaudal levels of the spinal cord. Comparison with the other immunohistochemical markers indicated that they were not primary sensory afferents. At least some of them probably originated from neuropeptide Y- and C-flanking peptide-immunoreactive neurons of the dorsal horn, that may be considered to be a subset of early-appearing interneurons.