Premium
L‐glutamate as an excitatory transmitter at the Drosophila larval neuromuscular junction.
Author(s) -
Jan L Y,
Jan Y N
Publication year - 1976
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.1976.sp011593
Subject(s) - excitatory postsynaptic potential , glutamate receptor , neuromuscular junction , biophysics , depolarization , neuromuscular transmission , membrane potential , reversal potential , chemistry , neuroscience , biology , patch clamp , electrophysiology , inhibitory postsynaptic potential , biochemistry , endocrinology , receptor
The possibility that L‐glutamate is the excitatory transmitter at the Drosophila larval neuromuscular junction and the ionic basis of its action on the muscle membrane are examined. 2. Iontophoretically applied L‐glutamate causes muscle depolarization (L‐glutamate potential) if and only if the L‐glutamate pipette is within a few mum of the nerve ending. D‐glutamate, substance P, ACh and GABA are ineffective. 3. Bath‐applied L‐glutamate produces similar changes in the time course and amplitude of miniature excitatory junctional potential (m.e.j.p.), excitatory junctional potential (e.j.p.) and the L‐glutamate potential. 4. Neuromuscular transmission and excitation‐contraction coupling are operative in a haemolymph‐like solution containing 1 mM L‐glutamate. 5. The reversal potentials of the e.j.p. and the L‐glutamate potential are identical to each other, changing similarly with changes in the ionic compositions of the external medium (twelve solutions). 6. The ionic dependence of the reversal potentials is predicted from an extended constant‐field equation using a ratio of sodium:potassium permeabilities of PNa/PK=1‐3, and a ratio of magnesium:potassium permeabilities of PMg/PK=4‐7. 7. It is concluded that L‐glutamate is, or is an agonist of, the excitatory transmitter at certain Drosophila larval neuromuscular junctions.