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The influence of concanavalin A on glutamate‐induced current fluctuations in locust muscle fibres.
Author(s) -
Mathers D A
Publication year - 1981
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.1981.sp013611
Subject(s) - locust , glutamate receptor , membrane potential , biophysics , conductance , concanavalin a , chemistry , hyperpolarization (physics) , reversal potential , membrane , electrophysiology , biology , biochemistry , neuroscience , physics , patch clamp , stereochemistry , botany , receptor , condensed matter physics , nuclear magnetic resonance spectroscopy , in vitro
1. The influence of the plant lectin Concanavalin A (ConA) on the properties of membrane channels opened by 25‐200 microM‐L‐glutamate in voltage‐clamped locust muscle fibres has been studied. Power spectral density plots of membrane current fluctuations were used to estimate the mean lifetime and conductance of glutamate‐induced channels. 2. Exposure to ConA (10 micrograms/ml.) increased the amplitude of the mean current evoked by 200 microM‐glutamate from 7.7 +/‐ 4.7 nA (mean +/‐ S.D.) to 81 +/‐ 57 nA (membrane potential ‐60 mV, temperature 16 degrees C). The mean conductance of glutamate‐induced channels (65 +/‐ 16.8 pS at 16 degrees C) was negligibly affected by the lectin. 3. In normal saline the mean lifetime of glutamate‐induced channels tau noise decreased on membrane hyperpolarization. After treatment with ConA (70 micrograms/ml.), tau noise become totally independent of membrane voltage when studied at potentials in the range ‐60 to ‐120 mV. The value of tau noise at the resting potential was little altered by the lectin.