Dual role of cGMP in modulation of macromolecule permeability of aortic endothelial cells.
The effect of guanosine 3',5'-cyclic monophosphate (cGMP) on cytosolic Ca2+ dynamics and associated alterations in macromolecule permeability was investigated in cultured monolayers of aortic endothelial cells. Addition of the membrane-permeable cGMP analogue 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP, 5 x 10(-4)M) or activators of the soluble (3-morpholinosydnonimine, 10(-5) M) or the particulate guanylyl cyclase (atrial natriuretic peptide, 10(-7) M) to unstimulated monolayers led to a decrease in permeability (8-BreGMP: 62 +/- 8% of control) without affecting low basal cytosolic Ca2+ concentration ([Ca2+]i, 87 +/- 8 nM). In contrast, under conditions of elevated [Ca2+]i (503 +/- 95 nM) and increased permeability (155 +/- 7% of control) induced by 10(-6) M ionomycin, 8-BrcGMP, 3-morpholinosydnonimine, or atrial natriuretic peptide provoked a further increase in permeability (8-BrcGMP: 255 +/- 27%). These agents failed to increase permeability when added before or after the ionomycin-triggered transitory rise in [Ca2+]i. The increase in permeability in response to 8-BrcGMP was due to a secondary further rise in [Ca2+]i (758 +/- 87 nM), which was abolished in the absence of extracellular Ca2+, indicating influx of exogenous Ca2+ as the cause. Changes in [Ca2+]i and permeability were inhibited, in the presence of the Rp diastereomer of 8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphothioate (2 x 10(-5) M), an inhibitor of the cGMP-dependent protein kinase. These findings show that, depending on [Ca2+]i, cGMP can play opposite roles in endothelial permeability in one and the same cell preparation.
Hölschermann
H
H
Physiologisches Institut, Justus-Liebig-Universität, Giessen, Germany.
Noll
T
T
Hempel
A
A
Piper
H M
HM
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000502:physiology*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D005110:Extracellular Space / Q000378:metabolism; D006162:Guanylate Cyclase / Q000378:metabolism; D046911:Macromolecular Substances; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D012709:Serum Albumin / Q000378:metabolism; D013268:Stimulation, Chemical; D013552:Swine
D046911:Macromolecular Substances; D012709:Serum Albumin; C016276:8-bromocyclic GMP; C002385:linsidomine; D009320:Atrial Natriuretic Factor; D008981:Molsidomine; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D002118:Calcium