Atriopeptin II and 8-bromo-cGMP lower Ca/sup 2 +/ in cultured aortic smooth muscle cells

Conference · Fri May 01 00:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6073475

Cornwell, T L; Rashatwar, S S; Lincoln, T M

Atriopeptin II (ANP) or 8-Bromo-cGMP (8-Br-cGMP) decreased the levels of intracellular Ca/sup 2 +/ in Angiotensin II- (Ang) or K/sup +/-stimulated cultured rat aortic smooth muscle cells. Cytoplasmic Ca/sup 2 +/, measured by fura-2 fluorescence, was maximal at 30 to 60 sec following the addition of either Ang or KCl. Pretreatment of smooth muscle cells with ANP or 8-Br-cGMP diminished peak levels of Ca/sup 2 +/ in response to Ang or KCl. Because the source of Ca/sup 2 +/ mobilized by KCl was extracellular while that mobilized by Ang was intracellular, these results suggested that ANP and 8-Br-cGMP did not inhibit the mobilization of Ca/sup 2 +/. This was further supported by studies on the effects of ANP and 8-Br-cGMP on inositol polyphosphate production in cells labelled with /sup 3/H-inositol. Ang, but not KCl, produced time-dependent increases in inositol polyphosphates. On the other hand, they have observed that cGMP-dependent protein kinase (cGPK), but not cAMP-dependent protein kinase, caused a 4-fold stimulation of Ca/sup 2 +/ ATPase activity in crude microsomal fractions from cultured rat aortic smooth muscle cells. These results suggest that ANP and 8-Br-cGMP may lower Ca/sup 2 +/ mobilized by Ang or KCl by enhancing Ca/sup 2 +/ efflux or resequestration possibly through the stimulation of a Ca/sup 2 +/ ATPase pump.

• Research Organization: Univ. of South Alabama, Mobile
• OSTI ID: 6073475
• Report Number(s): CONF-870644-; TRN: 87-037197
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
• Country of Publication: United States
• Language: English

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