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Nitric oxide from vascular smooth muscle cells: regulation of platelet reactivity and smooth muscle cell guanylate cyclase
Author(s) -
Mollace Vincenzo,
Salvemini Daniela,
Anggard Erik,
Vane John
Publication year - 1991
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1991.tb12481.x
Subject(s) - cycloheximide , nitric oxide , cyclic guanosine monophosphate , platelet , chemistry , arginine , omega n methylarginine , adenosine , incubation , vascular smooth muscle , cyclooxygenase , guanosine , medicine , endocrinology , biochemistry , nitric oxide synthase , biology , smooth muscle , enzyme , protein biosynthesis , amino acid
1 Incubation of smooth muscle cells (SMC) from bovine aorta for 3 min with human washed platelets treated with indomethacin (10 μ m ) promoted a cell number‐related inhibition of platelet aggregation induced by thrombin (40 mu ml −1 ). This inhibition was not attributable to products of the cyclooxygenase pathway for the SMC were also treated with indomethacin (10 μ m ). 2 The inhibitory activity of the SMC on platelet aggregation was enhanced by incubating the SMC with E. coli lipopolysaccharide (LPS, 0.5 μg ml −1 ) for a period of 9 to 24 h. This effect was attenuated when cycloheximide (10 μg ml −1 ) was incubated together with LPS. Cycloheximide did not prevent the inhibitory activity of the non‐treated cells. 3 The inhibition of platelet aggregation obtained with non‐treated or LPS‐treated SMC was potentiated by superoxide dismutase (SOD, 60 u ml −1 ) and ablated by oxyhaemoglobin (OxyHb, 10 μ m ). Preincubation of the SMC with N G ‐monomethyl‐ l ‐arginine ( l ‐NMMA, 30–300 μ m ) for 60 min prevented their antiaggregatory activity. This effect was reversed by concurrent incubation with l ‐arginine ( l ‐Arg, 100 μ m ) but not with d ‐arginine ( d ‐Arg, 100 μ m ). 4 Exposure of the non‐treated SMC (5 × 10 5 cells) to stirring (1000 r.p.m., 37°C) for 10 min led to a significant increase in their levels of guanosine 3′:5′‐cyclic monophosphate (cyclic GMP) but not adenosine 3′:5′‐cyclic monophosphate (cyclic AMP). l ‐NMMA (300 μ m ) attenuated the increase in cyclic GMP induced by stirring but did not affect the basal levels of cyclic GMP in the cells. The inhibitory activity of l ‐NMMA was reversed by co‐incubation with l ‐Arg (100 μ m ) but not d ‐Arg (100 μ m ). l ‐Arg alone had no effect on the levels of cyclic GMP. In the absence of stirring, a 10 min stimulation of the non‐treated SMC with glyceryl trinitrate (GTN, 200 μ m ) or atrial natriuretic factor (ANF, 10 −7 m ) led to an increase in the levels of cyclic GMP but not cyclic AMP. The increase in cyclic GMP promoted by GTN or ANF was not affected by l ‐NMMA. The levels of cyclic GMP were higher in the LPS (0.5 μg ml −1 , 18 h)‐treated cells (5 × 10 −5 ) and stirring was more effective in increasing the levels of cyclic GMP in these cells. 5 These findings support the idea that non‐treated or LPS‐treated cultured SMC can produce an NO‐like factor. Production by the latter requires protein synthesis as evidenced by blockade with cycloheximide. This NO‐like factor may play a role in the auto‐regulation of smooth muscle cell reactivity through a cyclic GMP‐dependent mechanism.