Chromaffin cells were co-transfected with EGFP + pcDNA, EGFP + α-synuclein, or EGFP + β-synuclein. Upon stimulation, fusion of endogenous granules (i.e, not containing exogenous transfected protein) was identified as discrete, punctate changes in DiI fluorescence. At these sites, the length of time P/S remained elevated was measured for 88 EGFP + pcDNA events, 137 EGFP + α-synuclein events, 52 EGFP + β-synuclein events and binned into three categories. The distributions were not significantly different.