The rate of aldehyde fixation of the exocytotic machinery in cultured hippocampal synapses.
The rate at which the transmitter release machinery is fixed by 2% glutaraldehyde at hippocampal synapses and the amount of release evoked by the fixative have been investigated. We recorded from hippocampal cells while fixative was applied with a rapid flow system. Release is blocked in less than a second and fixative-produced exocytosis is at most a few percent of what would be caused by a hypertonic stimulus that completely depletes the readily releasable pool of vesicles. The postsynaptic receptors for glutamate cease to respond to agonist with a time constant of approximately 3 s when fixative is applied. We conclude that some essential component of the exocytotic apparatus is fixed in less than a second and that the fixative does not significantly deplete the readily releasable pool.
Rosenmund
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C
Max-Planck-Institut für Biophysikalische Chemie, AG Zelluläre Neurobiologie, Göttingen, Germany.
Stevens
C F
CF
D000447:Aldehydes; D000818:Animals; D002478:Cells, Cultured; D005089:Exocytosis / Q000502:physiology*; D005976:Glutaral; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D006982:Hypertonic Solutions; D007700:Kinetics; D018377:Neurotransmitter Agents / Q000378:metabolism; D051381:Rats; D017470:Receptors, Glutamate / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D016707:Tissue Fixation / Q000379:methods*
D000447:Aldehydes; D006982:Hypertonic Solutions; D018377:Neurotransmitter Agents; D017470:Receptors, Glutamate; D015222:Sodium Channels; D005976:Glutaral