Regulation of blood pressure by glomus cells distributed in the artery

点击翻译按钮获取中文摘要

In the chicken, the thyroid gland, cranial and caudal parathyroid glands, carotid body and ultimobranchial gland are situated as a continuous series along the common carotid artery. The organs are supplied with branches that arise by one trunk from the middle portion of the common carotid artery. The glomus cells of the chicken carotid body express intense immunoreactivity for serotonin. Furthermore, serotonin-immunoreactive cells are widely ditributed in the wall of the common carotid artery and its branches supplying the endocrine organs (Kameda, 1990a). I have previously reported at the light microscopic level that glomus cells located in the wall of the common carotid artery and its branches express immunoreactivity for neuropeptide Y (NPY) (Kameda, 1990b). The present study examined the localization of NPY in the glomus cells at the electron microscopic level with the postembedding immunogold labeling. Gold particles representing NPY immunoreactivity were located exclusively on the secretory granules of the glomus cells. Furthermore, NPY gene expression was studied by means of in situ hybridization and northern blot analysis. In situ hybridization study with digoxigenin-labeled synthetic oligonucletotide probes from chicken NPY exon 2 indicated that the distribution of labeled cells was similar to that with immunohistochemistry. In addition, the data were supported by northern blot analysis with a chicken NPY exon 4 probe. mRNA from chicken common carotid artery and its branches was extracted and poly (A) ^+RNA was purified. The specific band for NPY gene was obtained in the extracts. These results provide the evidence that glomus cells distributed in the common carotid artery and its branches systhesize and secrete NPY.It is well known that NPY is a potent vasoconstrictor. The glomus cells in and around arteries may be involved in the regulation of arterial blood flow.