Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
1. Action potential (AP)-induced fluorescence transients were measured, using Ca2+ indicators and a spot-detection method, at single nerve terminals of a cultured Xenopus neuromuscular junction preparation with simultaneous measurement of neurotransmitter release. 2. Transients obtained using the low affinity Ca2+ indicator Oregon Green 488 BAPTA-5N (OGB-5N) exhibited rapid rising (t1/2 (time at which one-half of the peak fluorescence was attained) = 0.54 ms) and decaying (tau fast = 1.9 ms) phases. The higher affinity indicator Oregon Green 488 BAPTA-2 (OGB-2) produced transients with significantly slower kinetics (t1/2 = 2 ms; tau slow = 73 ms). 3. Tetanic stimulation elicited distinct increases in fluorescence in response to each AP. Each OGB-5N fluorescence increase was more rapid than those observed using OGB-2. Furthermore, a smaller proportion of residual fluorescence at the end of the train was observed using OGB-5N. 4. When OGB-5N was used, a significant [Ca2+] increase was observed prior to the release of neurotransmitter. This was not observed when OGB-2 was used. 5. We conclude that the use of localized optical detection coupled with low affinity Ca2+ indicators can help elucidate rapid changes in presynaptic [Ca2+] dynamics underlying evoked neurotransmitter release.
Augustine,
Calcium action in synaptic transmitter release.
1987, Pubmed
Augustine,
Calcium action in synaptic transmitter release.
1987,
Pubmed
Charlton,
Role of presynaptic calcium ions and channels in synaptic facilitation and depression at the squid giant synapse.
1982,
Pubmed
Escobar,
Localization of the site of Ca2+ release at the level of a single sarcomere in skeletal muscle fibres.
1994,
Pubmed
Escobar,
Kinetic properties of DM-nitrophen and calcium indicators: rapid transient response to flash photolysis.
1997,
Pubmed
Fogelson,
Presynaptic calcium diffusion from various arrays of single channels. Implications for transmitter release and synaptic facilitation.
1985,
Pubmed
Helmchen,
Calcium dynamics associated with a single action potential in a CNS presynaptic terminal.
1997,
Pubmed
Llinás,
Calcium role in depolarization-secretion coupling: an aequorin study in squid giant synapse.
1975,
Pubmed
Llinás,
The concept of calcium concentration microdomains in synaptic transmission.
1995,
Pubmed
Miledi,
Calcium transients recorded with arsenazo III in the presynaptic terminal of the squid giant synapse.
1981,
Pubmed
Regehr,
Calcium transients in cerebellar granule cell presynaptic terminals.
1995,
Pubmed
Roberts,
Localization of calcium signals by a mobile calcium buffer in frog saccular hair cells.
1994,
Pubmed
Sabatini,
Timing of neurotransmission at fast synapses in the mammalian brain.
1996,
Pubmed
Simon,
Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.
1985,
Pubmed
Sinha,
Presynaptic calcium dynamics and transmitter release evoked by single action potentials at mammalian central synapses.
1997,
Pubmed
Sugimori,
High-resolution measurement of the time course of calcium-concentration microdomains at squid presynaptic terminals.
1994,
Pubmed
Vergara,
Imaging of calcium transients during excitation-contraction coupling in skeletal muscle fibers.
1992,
Pubmed
Yazejian,
Direct measurements of presynaptic calcium and calcium-activated potassium currents regulating neurotransmitter release at cultured Xenopus nerve-muscle synapses.
1997,
Pubmed
,
Xenbase
Zucker,
Relationship between transmitter release and presynaptic calcium influx when calcium enters through discrete channels.
1986,
Pubmed
