Premium
On the quantal release of endogenous glutamate from the crayfish neuromuscular junction.
Author(s) -
Kawagoe R,
Onodera K,
Takeuchi A
Publication year - 1982
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 - 10.1113/jphysiol.1982.sp014053
Subject(s) - glutamate receptor , efflux , crayfish , biophysics , chemistry , neurotransmitter , neuromuscular junction , excitatory postsynaptic potential , biology , biochemistry , endocrinology , neuroscience , central nervous system , receptor , fishery
1. The abdominal slow flexor muscle was isolated from the crayfish (Cambarus clarkii) and placed in 150 microliters. Harreveld solution. The concentrations of glutamate and aspartate in this solution were measured by mass fragmentography. 2. Application of black widow spider venom (BWSV) produced a marked increase in the frequency of miniature excitatory post‐synaptic potentials (m.e.p.s.p.s). During the high frequency discharge of m.e.p.s.p.s, the glutamate content in the solution was significantly increased. There was an approximately linear relationship between the increase in the glutamate efflux produced by BWSV and the variance of the membrane potential fluctuation during high frequency discharge of m.e.p.s.p.s. 3. In most cases, the efflux of aspartate during control rest periods was smaller than that of glutamate. During the discharge of m.e.p.s.p.s produced by BWSV, the increase in the aspartate efflux was very small compared to glutamate. 4. Nerve stimulation caused a significant increase in the efflux of glutamate, but the change in the aspartate efflux was very small and not significant. 5. Application of methylene blue increased the frequency of m.e.p.s.p.s and glutamate efflux, but little, if any, increase was found in aspartate efflux. 6. It is concluded that glutamate is preferentially released from nerve terminals in a quantal fashion.