Immunocytochemistry and in situ hybridization of some vasoactive peptides and their receptors

点击翻译按钮获取中文摘要

1)The rat carotid body artery (CBA) and thoracic aorta under the hypoxic condition were investigated by electron microscopy, immunocytochernistry and in-situ hybridization. A remarkable increase in the number of Weibel-Palade (WP) bodies occurred in endothelial cells of the hypoxic CBA and thoracic aorta. The degree of immunoreactivities and gene expressions of both endothelin (ET)-1 and calcitonin gene-related peptide (CGRP) was significantly enhanced in the hypoxic samples when compared to the normoxic ones. Since WP bodies are involved in the storage and release of these peptides, the present findings indicate that ET-1 and CGRP, which are actively synthesized and released from endothelial cells, play a crucial role in the regulation of the blood flow through these vessels in the hypoxic condition.2)Vasoactivities after treatment with ET-1, and immunoreactivities for ET receptors were investigated on the rat superior mesenteric vasculature (SMV). By the me asurement of corrosion cast images of the SMVs, it was seen that ET-1. induces the remarkable vasocontraction of the distal arterial branches. The present immunocytochemistry showed that immunoreactivities for ETA receptors are localized to the sarcolemma of medial muscle, cells of the distal arterial branches. These findings suggest that ET-1-induced vasocontraction on the distal arterial branches is mediated from the ETA receptors. Immunoreactivities for ETB receptors were seen on the plasmalemma of endothelial cells in the SMVs. Since the WP bodies of these endothelial cells showed ultrastructural changes such as degranulation and exocytosis after treatment with sarafotoxin S6c, ETB receptor selective agonist, it seems likely that ETB receptors of the SMVs are involved in the release of the WP bodies.