The SNARE machinery is required for GTP-γ-S stimulated secretion.

[³H]5-HT–labeled and SLO-permeabilized platelets were first incubated with antibodies against NSF (0.15 mg/mL, 2E5), SNAP-23 (20 μg/mL), ab23 syntaxin 2 (60 μg/mL, pp2), syntaxin 7 (60 μg/mL antisyntaxin 7) and rabbit IgG (60 μg/mL) and mouse IgG (200 μg/mL). The platelets were then activated with 100 μmol/L GTP-γ-S and the release of [³H]5-HT and hexosaminidase was measured and normalized to control (buffer alone). The reactions were also performed by activating the platelet with GTP-γ-S on ice (Ice) or under ATP depletion condition (30 μg/mL apyrase; -ATP). It should be noted that the antibody inhibition results in a below background (no stimulus control) level of [³H]5-HT release hence the negative numbers for those samples.