Figure 3

Records of fura-2 Ca²⁺ imaging. A, average (mean; n = 30 HEK 293 cells) trace showing that LipoGen (1 μg/ml) failed to cause a rise in intracellular Ca²⁺ but that polymeric alkylpyridinium salt (Poly-APS; 1 μg/ml) increased intracellular Ca²⁺ measured as a change in fluorescence ratio (Fl.R). The rise in intracellular Ca²⁺ was indicative of pore formation. Inset record shows a trace of changes in intracellular Ca²⁺ from a single cell. B, average (mean; n = 19 HEK 293 cells) trace showing that lipofectamine (1 μg/ml) failed to cause a rise in intracellular Ca²⁺ but that polymeric alkylpyridinium salt (Poly-APS; 1 μg/ml) increased intracellular Ca²⁺, indicative of pore formation. Inset record shows a trace of changes in intracellular Ca²⁺ from a single cell. C, single cell trace of a Ca²⁺ transient evoked at 12°C by poly-APS.