Immunohistocytochemical localization of alpha human atrial natriuretic peptide in human atrium obtained from endomyocardial biopsy and cardiac surgery.

To demonstrate the localization of atrial natriuretic peptide (ANP), we were able to apply the indirect and avidin-biotin peroxidase complex (ABC) methods for immunohistocytochemical analysis on sections with routine fixation and embedding for conventional histopathological and ultrastructural examinations. Human right and/or left atrial myocardial specimens were obtained at cardiac surgery (n = 12) or by right atrial endomyocardial biopsy, employing Konno's catheter bioptome (n = 30). In both specimens, ANP-like immunoreactivity was observed mainly around the nuclei and in specific granules in atrial myocytes. These new techniques are, therefore, considered to be useful for clinical analysis employing minute human atrial specimens in various heart diseases.