Light- and electron-microscopic investigation of ANP-like immunoreactivity in aorta, carotid artery and cultured cardiac myocytes of the rat.

Abstract

In the present investigation we have sought for atrial natriuretic peptide (ANP)-like immunoreactivity in aorta, carotid artery, cultured aortic cells and cultured cardiac myocytes of the rat at the light-and electron-microscopic level using antibodies directed against atriopeptin II (5-27).Aortic and carotid aretery sections as well as cultured aortic cells did not show any ANP-specific immunoreactivity, preabsorbable by atriopeptin II or a-rat ANP (1-28).Cultured cardiac myocytes could be shown to contain ANP granules and secrete immunoreactive ANP.

Investigation of left atrial ANP-granule content and ANP release of isolated perfused rat heart.

“…For light-microscopic examination, 0.5 /Cm sections, and for electron microscopy, ultrathin sections were done. As described previously (9), semithin sections were stained according to the peroxidase-anti-peroxidase method using antibodies directed against atriopeptin II (rat . Ultrathin sections were stained with uranyl acetate and lead citrate and examined with a Zeiss EM 10 electron microscope.…”

“…Ultrathin sections were stained with uranyl acetate and lead citrate and examined with a Zeiss EM 10 electron microscope. To confirm that specific granules contained immunoreactive ANP, two ultrathin sections from each animal were stained with the protein A-gold technique, as described previously (9). Radioimmunoassay 1 ml samples of coronary perfusate were first acidified with 0.1 % trifluoracetic acid (TFA), applied on a Sep-Pak C18 cartridge (Waters, Milford, MA, USA) and the absorbed peptide eluted with a mixture of acetonitrile (60%) and TFA (0.1 %).…”