APα induces a rapid and transient [Ca2+]i rise in rat E18 hippocampal neurons in primary culture. Cells grown on glass cover slips were loaded with Fura-2 AM as described in the Methods. The [Ca2+]i was determined on single cells in HBSS medium. (A) Images represent calcium fluro-2 fluorescence in rat hippocampal neurons under vehicle control (top) and 500 nM APα (bottom). A fluorescent gradient of fluorescence ratio of 340 nm/380 nm is presented at the right side of the images. (B) A linear regression and the multiple correlation coefficient R-square value indicate the perfect correlation between fluorescence ratio of 340 nm/380 nm and [Ca2+]. (C) APα induced rapid and transient responses of [Ca2+]i recorded in a time course and expressed as the fluorescence ratio between 340 nm/380 nm, which is a representative of three different experiments. (D) Bar graph represents the summary of [Ca2+]i in response to control, vehicle control, and 500 nM APα. Data are mean ± SEM (*p < 0.05 compared to control neurons; N = 3 experiments with 36 neurons/condition/experiment). No changes in [Ca2+]i were observed under control or vehicle control conditions. With the addition of 500 nM APα, three types of calcium responses were observed in neurons: high (defined as an increase in [Ca2+]i >65 nM over the baseline); low (defined as an increase in [Ca2+]i <45 nM over the baseline); and no response (defined as neurons that did not show a measurable increase in [Ca2+]i over their baseline).
Wang and Brinton BMC Neuroscience 2008 9(Suppl 2):S11 doi:10.1186/1471-2202-9-S2-S11