Sodium azide, a bacteriostatic preservative contained in commercially available laboratory reagents, influences the responses of human platelets via the cGMP/PKG/VASP pathway.

Objective: The bacteriostatic preservative sodium azide (NaN(3)) activates soluble guanylate cyclase (sGC) in vascular tissues, thus elevating cellular 3',5'-cyclic guanosine monophosphate (cGMP). Because the sGC/cGMP pathway is involved in the control of platelet aggregation, we investigated whether in human platelets NaN(3) influences the responses to agonists, cGMP levels and cGMP-regulated pathways.

Design And Method: Concentration- and time-dependent effects of NaN(3) (1-100 micromol/L; 5-60 min incubation) on ADP- and collagen-induced aggregation, NO synthase (NOS) activity, cGMP synthesis and vasodilator-stimulated phosphoprotein (VASP) phosphorylation at Ser239 were investigated in platelets from 21 healthy individuals.

Results: NaN(3) exerted concentration- and time-dependent antiaggregatory effects starting from 1 micromol/L (IC(50) with 5-min incubation: 2.77+/-0.35 micromol/L with ADP and 4.64+/-0.48 micromol/L with collagen) and significantly increased intraplatelet cGMP levels and phosphorylation of VASP at Ser239 at 1-100 micromol/L; these effects were prevented by sGC inhibition, but not by NOS inhibition.

Conclusions: NaN(3) exerts antiaggregatory effects in human platelets via activation of the sGC/cGMP/VASP pathway. This biological effect must be considered when azide-containing reagents are used for in vitro studies on platelet function.