Localization of α1-adrenoceptors in rat and human hearts by immunocytochemistry

✍ Scribed by Wolfgang Schulze; Michael L. X. Fu

• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 591 KB
• Volume: 163-164
• Category: Article
• ISSN: 0300-8177
• DOI: 10.1007/bf00408653

✦ Synopsis

The localization of the c~ adrenoceptors (Ctl-AR) in the heart tissues from rat and human and in the cultured heart cells from neonatal rats was studied by indirect immunofluorescence and postembedding electronmicroscopical immuno-gold technique. With antipeptide antibodies directed against the second extracellular loop of the human a~-AR (AS sequence 192-218), this receptor was found to be localized along the sarcolemma in both human and rat hearts. Similar localization sites were detected in cultivated rat neonatal cardiomyocytes. Beside the localization in cardiomyocytes, al-AR were identified in endothelial cells of capillaries and smooth muscle cells of coronary vessels, in neuronal endings, in mast cells of cultivated heart cells but not, or in less amount in fibroblasts. Interestingly, in the right atrium of rat heart the localization of al-AR was found to be near or on atrial natriuretic factor (ANF) granules, providing the basis for the a-adrenergic influence on ANF release. The immunocytochemical studies further confirm and complete the findings known by using autoradiographic binding studies with specific ligands. (Mol Cell Biochem 163/164: 159-165, 1996)