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Aim:Ca~(2+)release from the endoplasmic reticulum(ER)is an integral component ofneuronal Ca~(2+)signaling.The present study is to investigate properties of localCa~(2+)release events in superior cervical ganglion(SCG)neurons.Methods:Pri-mary cultured SCG neurons were prepared from neonatal rats(P3-P7).Low con-centration of caffeine was used to induce Ca~(2+)release from the ER Ca~(2+)store,andintracellular Ca~(2+)was recorded by high-resolution line scan confocal imaging andthe Ca~(2+)indicator Fluo-4.Results:Two populations of local Ca~(2+)release eventswith distinct temporal characteristics were evoked by 1.5 mmol/L caffeine near thesurface membrane in the soma and the neurites of SCG neurons.Brief eventssimilar to classic Ca~(2+)sparks lasted a few hundreds of milliseconds,whereas long-lasting events displayed duration up to tens of seconds.Typical somatic andneurite sparks were of 0.3-and 0.52-fold increase in local Fluo-4 fluorescence,respectively.Typical Ca~(2+)glows were brighter(ΔF/F_0 approximately 0.6),butwere highly confined in space.The half maximum of full duration of neurite sparkswas much longer than those in the soma(685 vs 381 ms).Conclusion:Co-exist-ence of Ca~(2+)sparks and Ca~(2+)glows in SCG neurons indicates distinctive localregulation of Ca~(2+)release kinetics.The local Ca~(2+)signals of variable,site-specifictemporal length may bear important implications in encoding a“memory”of thetrigger signal.
Aim: Ca ~ (2+) release from the endoplasmic reticulum (ER) is an integral component of uronal Ca ~ (2+) signaling.The present study is to investigate properties of local Ca ~ (2+) release events in superior cervical ganglion SCG) neurons. Methods: Pri-mary cultured SCG neurons were prepared from neonatal rats (P3-P7). Low con-centration of caffeine was used to induce Ca 2+ release from the ER Ca 2+ store , and intracellular Ca ~ (2+) was recorded by high-resolution line scan confocal imaging and the Ca ~ (2+) indicator Fluo-4.Results: Two populations of local Ca 2+ release events with distinct temporal characteristics were evoked by 1.5 mmol / L caffeine near the surface membrane in the soma and the neurites of SCG neurons. Event event similar to classic Ca ~ (2+) sparks lasted a few hundreds of milliseconds, long long-lasting events displayed up to tens of seconds.Typical somatic andneurite sparks were 0.3-and 0.52-fold increase in local Fluo-4 fluorescence, respectively.Typical Ca 2+ glows were brighte r (ΔF / F_0 approximately 0.6), butwere highly confined in space. The half maximum of full duration of neurite sparks was much longer than those in the soma (685 vs 381 ms) .Conclusion: Co-exist-ence of Ca ~ (2 +) sparks and Ca ~ (2+) glows in SCG neurons indicates distinctive local regulation of Ca ~ (2+) release kinetics.The local Ca ~ (2+) signals of variable, site-specific temporal length may bear important implications in encoding a “memory ” of thetrigger signal.