Avtor/Urednik		Kržan, Mojca; Stenovec, Matjaž; Kreft, Marko; Pangršič, Tina; Grilc, Sonja; Haydon, Philip G; Zorec, Robert
Naslov		Calcium-dependent exocytosis of atrial natriuretic peptide from astrocytes
Tip		članek
Vir		J Neurosci
Vol. in št.		Letnik 23, št. 5
Leto izdaje		2003
Obseg		str. 1580-3
Jezik		eng
Abstrakt		Astrocytes are non-neuronal cells in the CNS, which, like neurons, are capable of releasing neuroactive molecules. However, the mechanism of release is ill defined. In this study, we investigated the mechanism of release of atrial natriuretic peptide (ANP) from cultured cortical astrocytes by confocal microscopy. To study the discharge of this hormone, we transfected astrocytes with a construct to express pro-ANP fused with the emerald green fluorescent protein (ANP.emd). The transfection of cells with ANP.emd resulted in fluorescent puncta in the cytoplasm that represent secretory organelles. If ANP is released by exocytosis, in which the vesicle fuses with the plasma membrane, then the total intensity of the green fluorescing probe should decrease, whereas the vesicle membrane is incorporated into the plasma membrane. To monitor exocytosis, we labeled the membrane with the fluorescent styryldye FM 4-64, a reporter of cumulative exocytosis. The application of ionomycin to elevate cytoplasmic [Caz+] increased the fluorescence intensity of FM 4-64, whereas that of ANP.emd decreased. These effects were not observed in the absence of extracellular CaZ+, suggesting that ANP is released by regulated Ca2+-dependent exocytosis from astrocytes.
Deskriptorji		ASTROCYTES EXOCYTOSIS CALCIUM ATRIAL NATRIURETIC FACTOR IONOMYCIN MICROSCOPY, CONFOCAL CELLS, CULTURED RATS