Strontium as a Substitute for Calcium in the Process of Transmitter Release at the Neuromuscular Junction

@article{Miledi1966StrontiumAA,
  title={Strontium as a Substitute for Calcium in the Process of Transmitter Release at the Neuromuscular Junction},
  author={Ricardo Miledi},
  journal={Nature},
  year={1966},
  volume={212},
  pages={1233-1234}
}
  • R. Miledi
  • Published 1 December 1966
  • Biology
  • Nature
AT the neuromuscular junction1, as well as at neuronal synapses2, calcium plays an essential and direct part in the process whereby depolarization of the presynaptic nerve terminal leads to release of the transmitter substance. It is also known that a nerve impulse releases the transmitter in quantal form, that is, in discrete multi-molecular amounts of a fairly standard size, and that calcium acts by increasing the probability of such transmitter release. The question is raised whether other… 
View on Nature
ncbi.nlm.nih.gov
199 Citations
Highly Influential Citations
9
Background Citations
50
Methods Citations
13
Results Citations
4

199 Citations

Citation Type

Citation Type

Lanthanum Ions abolish the “Calcium Response” of Nerve Terminals
TLDR
It is found that lanthanum not only failed to substitute for calcium, but blocked transmission when added to a solution containing the normal amount of calcium.
Equivalence of Ca2+ and Sr2+ in transmitter release from K+-depolarised nerve terminals
TLDR
The relative abilities of Ca2+ and Sr2+ in supporting the augmented m.e.p. frequency seen in high K+ Ringer's solutions are compared and it is reported here that they are qualitatively and quantitatively equivalent, in contrast to their differences in the nerve impulse-evoked e.p.'s.
Role of Calcium Ions in Neuromuscular Transmission
TLDR
If the effect of partial or total calcium deprivation is examined on the various steps leading from the nerve stimulus to muscle contraction, almost every stage is found to be affected to some extent.
Neuromuscular transmission in Ca2+-free extracellular solution
  • S. Grishin
  • Biology
    Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology
  • 2016
TLDR
The review illustrates how the equimolar substitution of external Ca2+ by other polyvalent cations affects the parameters of nonquantum, spontaneous, and induced quantum exocytosis of the neuromediator, as well as endocytotic and the activities of acetylcholinesterase and postsynaptic receptors.
Synaptic physiology
TLDR
The sequence of events from axon terminal depolarization to integration of information by summation of separate synaptic effects is described, which adds to the effect from the simultaneous action of many synapses to permit information from many sources to be combined in a single neuron.
Kinetic analyses of transmitter release in neuromuscular transmission.
The Involvement of Alkaline Earth Cations in the Control of Acetylcholine Release
TLDR
The ratio of the amplitudes of the electrical events associated with neurally-evoked ACh release to the spontaneous potentials serves as a reliable estimate of the mean number of ACh quanta released synchronously by a nerve impulse.
ON THE CONDUCTANCE PATHWAY TRAVERSED BY STRONTIUM IN MEDIATING THE ASYNCHRONOUS RELEASE OF ACETYLCHOLINE BY MOTOR NERVE IMPULSES
TLDR
The results suggest that Sr2+ mediates asynchronous evoked transmitter release through the conventional calcium conductance channel.
On the role of mitochondria in transmitter release from motor nerve terminals.
TLDR
The experimental results are explained on the hypothesis that spontaneous release of transmitter reflects the resting level of intracellular free calcium and the evoked release reflects the sum of the resting calcium andthe calcium brought in by the action potential.
Mechanisms of the facilitation of neurotransmitter secretion in strontium solutions
TLDR
It is shown that the facilitation sites underlying the first and early components had lower affinities for Sr ions than for Ca ions, and increases in facilitation in strontium solutions in conditions of high-frequency rhythmic activity resulted from two mechanisms.
...
...

References

SHOWING 1-5 OF 5 REFERENCES
The effect of calcium on acetylcholine release from motor nerve terminals
  • B. Katz, R. Miledi
  • Biology
    Proceedings of the Royal Society of London. Series B. Biological Sciences
  • 1965
TLDR
The method of external focal recording from the neuromuscular junction has been used and it is concluded that the action of calcium is concerned directly with the release of the transmitter, and not indirectly by facilitating propagation or increasing the amplitude of the terminal nerve spike.
The measurement of synaptic delay, and the time course of acetylcholine release at the neuromuscular junction
  • B. Katz, R. Miledi
  • Biology
    Proceedings of the Royal Society of London. Series B. Biological Sciences
  • 1965
TLDR
The synaptic interval arises chiefly from a delay in the release of transmitter after the arrival of the nerve impulse, and the contribution of various factors to the minimum synaptic delay are discussed.
Propagation of electric activity in motor nerve terminals
  • B. Katz, R. Miledi
  • Biology
    Proceedings of the Royal Society of London. Series B. Biological Sciences
  • 1965
TLDR
External micro-electrodes were used to stimulate non-myelinated motor nerve terminals and to record pre- and post-synaptic responses at the neuromuscular junction of the frog to determine the velocity of impulse propagation in motor nerve endings.
On the replacement of calcium in certain neuro‐muscular mechanisms by allied substances 1
TLDR
The answers to many questions which arise in the euquiry as to physiological relations between calcium, strontium and barium have been given by the classical researches of Ringer.
The action of calcium on neuronal synapses in the squid
TLDR
The isolated stellate ganglion of the squid was studied with intracellular and extracellular micro‐electrodes and 1‐3 small presynaptic spikes could be recorded from within the post‐synaptic axon.