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Dependence on temperature of the effect of dinitrophenol on the release of transmitter quanta at neuromuscular junctions in the mouse diaphragm
Author(s) -
Nishimura Masakazu,
Taquahashi Yuhji,
Fujita Keiko,
Satoh Eiki,
Shimizu Yoshio
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15492.x
Subject(s) - 2,4 dinitrophenol , diaphragm (acoustics) , extracellular , chemistry , biophysics , dinitrophenol , intracellular , neuromuscular junction , ion , biochemistry , biology , neuroscience , physics , organic chemistry , acoustics , loudspeaker
1 The frequencies (F, s −1 ) of miniature endplate potentials and the quantal content (m) of endplate potentials were measured intracellularly and simultaneously at mouse diaphragm endplates in a bathing solution that contained 0.6 mM Ca 2+ ions and 5 mM Mg 2+ ions. 2 Twin pulses at 4 ms intervals gave the quantal contents of the first (m1) and second (m2) responses. The ratio of m2/m1 was taken as an indicator of the temporal facilitation of the release of transmitter. 3 Dinitrophenol (DNP, 10 μ m ) increased the values of F and m at 36°C. This effect did not depend on extracellular Ca 2+ ions. 4 The potentiating effect of DNP disappeared at 24°C but the value of m2/m1 remained constant. 5 These results suggest that the effect of DNP is modifiable by temperature which can affect systems that control the intracellular metabolism of Ca 2+ ions.