Role of calcium in stretch-induced release and mRNA synthesis of natriuretic peptides in isolated rat atrium |
| |
Authors: | M Laine L Id O Vuolteenaho H Ruskoaho M Weckström |
| |
Institution: | (1) Department of Physiology, Biocenter Oulu, University of Oulu, Kajaanintie 52 A, 90220 Oulu, Finland, FI;(2) Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Kajaanintie 52 A, 90220 Oulu, Finland, FI |
| |
Abstract: | To investigate the role of Ca2+ in stretch-induced synthesis and release of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) isolated
superfused rat atria were stretched by raising intra-atrial pressure. The immunoreactive (ir-) ANP and BNP concentrations
were analysed by radioimmunoassay and the corresponding mRNA levels were quantified by Northern blot and dot blot analyses.
Stretch-induced ir-ANP release and a rise in BNP mRNA levels increased at high (3.0 mM) compared to low (0.5 mM) extracellular
Ca2+ concentration (Ca2+]o). Moreover, the adaptation of stretch-induced ir-ANP release was dependent on Ca2+]o. Atrial BNP mRNA levels were increased by stretch also in non-paced, electrically silent atria, where voltage-activated Ca2+ channels are not activated. The stretch-induced rise in BNP mRNA was blocked by gadolinium (80 μM), but not by the L-type
channel blocker diltiazem (3.0 μM). This study indicates that both the stretch-secretion coupling of ir-ANP release and the
pressure-stimulated synthesis of BNP mRNA are Ca2+-dependent processes. Gadolinium inhibits the stretch-stimulated rise in BNP mRNA levels in contracting and non-contracting
atria, which is similar to its ability to block stretch-activated ir-ANP release, suggesting the involvement of Ca2+-permeable stretch-activated channels.
Received: 29 April 1996 / Received after revision and accepted: 17 June 1996 |
| |
Keywords: | ANP BNP Gadolinium Secretion Exocytosis Mechanotransduction |
本文献已被 SpringerLink 等数据库收录! |
|