Calcium dependence of presynaptic calcium current and post-synaptic response at the squid giant synapse.
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چکیده
منابع مشابه
Calcium dependence of presynaptic calcium current and post-synaptic response at the squid giant synapse.
1. Neurotransmitter release has a non-linear dependence upon the external Ca concentration, [Ca]o. This may be due to a 'co-operative' action of Ca in triggering release. The dependence of presynaptic Ca currents and post-synaptic currents (p.s.c.s) upon [Ca]o was examined at voltage-clamped 'giant' synapses of squid to determine whether this 'co-operativity' occurs during or after influx of Ca...
متن کاملPresynaptic calcium diffusion and the time courses of transmitter release and synaptic facilitation at the squid giant synapse.
At the squid giant synapse, a presynaptic action potential is accompanied by an influx of calcium ions that continue to be detectable with arsenazo III microspectrophotometry for several seconds. Nevertheless, transmitter release occurs phasically, lasting only about 2 msec. If a second action potential follows within about 100 msec after the first, it releases more transmitter. In this paper, ...
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Synaptic transmission was studied at the squid giant synapse with voltage clamp control of both presynaptic and postsynaptic cells. Because presynaptic voltage gradients can complicate interpretation of electrophysiological data obtained from this preparation, we used local Ca application to restrict Ca influx and transmitter release to a short and relatively isopotential portion of the elongat...
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Voltage-gated calcium channels are well characterized at neuronal somata but less thoroughly understood at the presynaptic terminal where they trigger transmitter release. In order to elucidate how the intrinsic properties of presynaptic calcium channels influence synaptic function, we have made direct recordings of the presynaptic calcium current (I(pCa)) in a brainstem giant synapse called th...
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The role of Ca in transmitter release and facilitation has been examined at the squid giant synapse by evaluating the effect of changes in the external concentration of Ca on the excitatory postsynaptic potential (EPSP). Changes in Ca were achieved by means of an arterial perfusion technique, circumventing the diffusion barrier that exists between the synapse and the bathing medium. Transmitter...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1986
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1986.sp016347