Effects of atrial and brain natriuretic peptides upon cyclic GMP levels, potassium transport, and receptor binding in rat astrocytes

✍ Scribed by K. Beaumont; P. K. Tan

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 661 KB
• Volume: 25
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490250215

✦ Synopsis

The ability of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) to alter cyclic GMP levels and NaKCl cotransport in rat neocortical astrocytes was determined. At concentrations of lop9-10W6M, rat ANP99-126 (rANF), rat ANP,,,-,,, (auriculin B), and rat ANP,,,,,, (atriopeptin 111) stimulated 6-to 100-fold increases in cyclic GMP levels. Porcine BNP (pBNP) and rat BNP (rBNP) were 20%-90% as effective as rANF over most of this concentration range, although 10-6M pBNP produced a greater effect than rANF. NaKCI cotransport as measured by bumetanide-sensitive "Rb + influx was not altered by exposure of astrocytes to 1OW6M rANF, pBNP, or rBNP. Both pBNP and rBNP, as well as rat ANP,,,,,, (atriopeptin I) and des[gln", ser", g1yZo, leu", g1yZ2] ANF,,,-NH, (C-ANF,,,) strongly competed for specific "'I-rANF binding sites in astrocyte membranes with affinities ranging from 0.03 to 0.4 nM, suggesting that virtually all binding sites measured at subnanomolar concentrations of lZ5I-rANF were of the ANP-C (ANF-R,) receptor subtype. These receptors are thought to serve a clearance function (Maack et al.: Science 238:675-678, 1987) and may be linked to a guanylate cyclase activity that is chemically and pharmacologically distinct from that coupled to ANP-A (ANF-R,) receptors (Fethiere et al.: Mol Pharmacol35:584-592, 1989). ANP receptors on astrocytes may function in limiting the access of ANP and BNP to neurons involved in body fluid and cardiovascular regulation.