FIGURE 1.8. SynaptopHluorin as a reporter of stimulus-evoked transmitter release: in vitro validation.


SynaptopHluorin as a reporter of stimulus-evoked transmitter release: in vitro validation. (A) Resting fluorescence and optical signals imaged from an olfactory bulb slice of a mouse expressing spH in olfactory receptor neurons. The position of the stimulating electrode is indicated in gray. Traces show the stimulus-evoked spH signal measured from the bright glomerulus. Traces are unfiltered signals from a single trial, imaged at 125 Hz. “Flat” trace shows the signal from pixels overlying the axon, averaged across eight trials and low-pass filtered at 20 Hz. Thin vertical line indicates time of nerve shock. (B) Longer record, obtained from a different preparation, demonstrating the slow decay of the evoked spH signal. Trace is average of four trials, imaged at 40 Hz. (C) Shock-evoked spH signals recorded from a glomerulus under different external Ca2+ concentrations ([Ca2+]ext). Each trace is the average of four trials and is bleach-subtracted and low-pass filtered at 15 Hz. (D) Plots of spH signal (open squares) and external tufted cell EPSC amplitude (closed circles, recorded from different preparations) as a function of [Ca2+]ext. Response amplitudes are normalized to the amplitude at 2 mM [Ca2+ext]. Error bars are s.e.m. Solid curves show fits of each dataset to the Hill equation. The fits are nearly identical for the spH and EPSC recordings. ([A,B] From McGann, J.P. et al., Neuron, 48: 1039–1053, 2005; [C,D] from Wachowiak, M. et al., J Neurophysiol, 94: 2700–2712, 2005.)

From: Chapter 1, Optical Imaging of Brain Activity In Vivo Using Genetically Encoded Probes

Cover of In Vivo Optical Imaging of Brain Function
In Vivo Optical Imaging of Brain Function. 2nd edition.
Frostig RD, editor.
Boca Raton (FL): CRC Press/Taylor & Francis; 2009.
Copyright © 2009, Taylor & Francis Group, LLC.

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