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Noradrenaline synchronizes evoked quantal release at frog neuromuscular junctions
Author(s) -
Bukcharaeva Ella A.,
Kim Kira C.,
Moravec J.,
Nikolsky E. E.,
Vyskočil F.
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.0879s.x
Subject(s) - neuromuscular transmission , neuromuscular junction , neurotransmission , neuroscience , presynaptic inhibition , synapse , chemistry , hibernation (computing) , biophysics , biology , endocrinology , receptor , biochemistry , state (computer science) , algorithm , computer science
1 Noradrenaline (NA) increases synaptic efficacy at the frog neuromuscular junction. To test the hypothesis that one of the actions of NA is to shorten the period over which evoked quanta are released, we measured the latencies of focally recorded uniquantal endplate currents (EPCs). 2 NA shortened the release period for evoked quantal release. The interval between the time when responses with minimal delay appeared and the point at which 90 % of all latencies had occurred was shortened in the presence of 1 × 10 −5 M NA by about 35 % at 20 °C and by about 45 % at 8 °C. Inhibitor and agonist experiments showed that NA acts on a β‐adrenoreceptor. 3 The better synchronization of release significantly increased the size of reconstructed multi‐ quantal EPCs. This suggests that NA facilitates synaptic transmission by making the release of quanta more synchronous. 4 The synchronizing action of NA might potentiate neuromuscular transmission during nerve regeneration, transmitter exhaustion and other extreme physiological states where the quantal content is reduced, such as survival in cold and hibernation.