Multicompartment diffusion and reaction modeling system applied to transmitter-mediated photoreception

Grisell, Ronald D.; Andresen, Michael

doi:10.1016/0010-4825(79)90028-3

Cited by 2 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Calcium influx and extrusion were assumed to occur uniformly throughout the surface of the outermost shell. Models of this sort have been widely used to simulate calcium transients in neurons (Blumenfeld et al, 1992;Connor and Nikolakopoulou, 1982;Grisell and Andresen, 1979;Nowycky and Pinter, 1993;Sala and Hernandez-Cruz, 1990;Smith and Zucker, 1980). As seen in Fig.…”

Section: Simulations Examining the Effects Of Diffusionmentioning

confidence: 99%

Optical Measurement of Presynaptic Calcium Currents

Sabatini

Regehr

1998

Biophysical Journal

116

View full text Add to dashboard Cite

Measurements of presynaptic calcium currents are vital to understanding the control of transmitter release. However, most presynaptic boutons in the vertebrate central nervous system are too small to allow electrical recordings of presynaptic calcium currents (I(Ca)pre). We therefore tested the possibility of measuring I(Ca)pre optically in boutons loaded with calcium-sensitive fluorophores. From a theoretical treatment of a system containing an endogenous buffer and an indicator, we determined the conditions necessary for the derivative of the stimulus-evoked change in indicator fluorescence to report I(Ca)pre accurately. Matching the calcium dissociation rates of the endogenous buffer and indicator allows the most precise optical measurements of I(Ca)pre. We tested our ability to measure I(Ca)pre in granule cells in rat cerebellar slices. The derivatives of stimulus-evoked fluorescence transients from slices loaded with the low-affinity calcium indicators magnesium green and mag-fura-5 had the same time courses and were unaffected by changes in calcium influx or indicator concentration. Thus both of these indicators were well suited to measuring I(Ca)pre. In contrast, the high-affinity indicator fura-2 distorted I(Ca)pre. The optically determined I(Ca)pre was well approximated by a Gaussian with a half-width of 650 micros at 24 degrees C and 340 micros at 34 degrees C.

show abstract