STUDY OF IMMUNOHISTOCHEMICAL LOCALIZATION OF BRAIN NATRIURETIC PEPTIDE-LIKE IMMUNOREACTIVE SUBSTANCE IN THE RAT BRAIN AND PERIPHERAL TISSUES / 解剖学报

ABSTRACT

Brain natriuretic peptide(BNP) is a recently discovered novel neuropeptide of 26 amino acid residues, isolated from porcine brain, that is of similar potency to atrial natriuretic factor(ANF) in natriuretic, diuretic, hypotensive and smooth muscle relaxant activities. we used a highly selective antisera against BNP raised in rabbit to observe its distribution and localization in some brain areas and some other peripheral tissues by utili zing high sensitive avidin-biotin-peroxidase complex technique. Positive brain natriuretic peptide immunoreactive (BNPir) fibers and cell bodies were observed in the lateral hypothalamic area, caudate-putamen, hippocampus, amygdala, and supraoptic and paraventricular nuclei. A lot of BNPir granules were also found in rat atria. They were of similar localization to that of ANF. Most of the specific granules were accumulated in cytoplasm at both nuclear poles of atrial myocytes. The BNP immunoreactivity is less intense than that of the ANF. Some of scanty, diffuse and fine BNPir granules could also be observed in ventricular myocytes.The coexistence of both BNP and ANF in the brain and heart indicates that BNP may function as a neuropeptide and circulating hormone, and suggests the possibility that the physiological effects such as diuretic natriuretic, hypotensive and smooth muscle relaxant activities so far thought to be mediated by ANF may be regulated through a dual mechanism involving both BNP and ANF. In addition, some BNPir positive cells were also present in the anterior and intermediate lobes of rat pituitary gland. The significance of BNP in hypophysis would be elucidated in the further studies.