A. Wernig et al., DIFFERENTIAL SENSITIVITY TO MG2-BLOCK AND TUBOCURARINE-BLOCK OF FROG NEUROMUSCULAR-JUNCTIONS IN SUMMER AND WINTER(), Neuroscience letters, 207(1), 1996, pp. 41-44
Several parameters of transmitter release in neuromuscular junctions w
ere compared in 'winter' and 'summer' frogs. In low Ca2+/high Mg2+-blo
ck, the quantal content m of endplate potentials was similar for both
groups. In curarized junctions, however, endplate potentials were abou
t twice as large in winter as in summer, and facilitation was lower an
d depression higher. This indicates that transmitter release is higher
in winter junctions. This is not reflected in Mg2+-block, suggesting
that strong calcium deprivation may suppress release in winter more st
rongly than in summer junctions.