Inhibition of endocytosis suppresses the nitric oxide-dependent release of Cl- in retinal amacrine cells
Fig 7
Dynamin inhibitors interfere with voltage-dependent Ca2+ signaling and voltage-gated Ca2+ currents.
A-D, (Left) Ca2+ imaging data from OGB 488-loaded (1 μM) ACs. A 50 mM K+ -induced depolarization causes an increase in OGB fluorescence, which indicates an increase in [Ca2+]. Acute exposure of dynasore, Dyngo 4a, Dynole 34–2 and MiTMAB all reduce the voltage-dependent Ca2+ increases. Mean quantified F/F0 ± SD. Data collected from regions of interest (ROIs) in cell bodies. (Control and dynasore, n = 44; p < 0.05; Control and Dyngo n = 56; p < 0.0001; Control and MiTMAB n = 44, p< 0.0001; control and Dynole 34–2, n = 63, p < 0.0001, paired t-tests). E. Schematic of the voltage ramp protocol used to elicit voltage-gated Ca2+ currents. Cells in the ruptured patch configuration were voltage-clamped at -70 mV for 500 ms. Then the voltage was stepped briefly down to -90 mV, ramped to +50 mV, and then back down to -70 mV. F, Representative voltage-clamp recordings from four representative ACs. Dynasore, Dynole 34–2, and MiTMAB reduce the peak amplitude of the Ca2+ currents and the effects were at least partially reversible. G, Mean peak amplitudes are plotted for four populations of cells (dynasore n = 6, p<0.01; MiTMAB n = 5, p<0.01; Dynole 34–2 n = 5, p<0.01; Dyngo 4a n = 5, p = 0.5, paired t-tests).