Atrial natriuretic peptide enhances IL-1 beta-stimulated nitric oxide production in cultured rat vascular smooth muscle cells.
OBJECTIVE
To elucidate the effect of atrial natriuretic peptide (ANP) on cytokine-induced nitric oxide (NO) production, we examined whether ANP affects IL-1 beta-stimulated NO production and inducible NO synthase (iNOS) mRNA expression in cultured rat vascular smooth muscle cells (VSMC).


METHODS
VSMC were incubated with test agents for 24 h. The nitrite concentration of the culture medium, a stable-end product of NO, was measured by the column reduction method. NOS mRNA expression was analyzed by Northern blotting. The intracellular cAMP content was measured by enzyme immunoassay. cAMP-dependent kinase (PKA) activity was determined by a PKA assay system.


RESULTS
IL-1 beta stimulated nitrite production in VSMC. ANP (10 nM to 1 mM) enhanced the nitrite production and iNOS mRNA expression in the presence of IL-1 beta. Both 8-bromo-guanosine 3',5'-cyclic monophosphate (8-br-cGMP) and dibutylyl adenosine 3',5'-cyclic monophate enhanced IL-1 beta-induced nitrite production. The effects of these two nucleotide donors on the nitrite production were not additive, suggesting a common pathway. KT 5720, an inhibitor of PKA, abolished the enhancement of nitrite production by ANP and 8-br-cGMP, while KT 5823, an inhibitor of cGMP-dependent protein kinase, did not inhibit the enhancement. In the in vitro assay 8-br-cGMP increased PKA activity.


CONCLUSIONS
ANP and cGMP enhanced IL-1 beta-induced NO production in VSMC. PKA rather than PKG may be involved in the enhancement.
Iimura
O
O
Department of Nephrology, Jichi Medical School, Tochigi, Japan.
Kusano
E
E
Homma
S
S
Takeda
S
S
Ikeda
U
U
Shimada
K
K
Asano
Y
Y
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D015152:Blotting, Northern; D002227:Carbazoles; D000242:Cyclic AMP / Q000378:metabolism; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000819:agonists / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D011758:Pyrroles / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins
D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; D007375:Interleukin-1; D011758:Pyrroles; D012333:RNA, Messenger; D011994:Recombinant Proteins; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D003995:Dibutyryl Cyclic GMP; C057416:KT 5720; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP