Abstract
In a temperature-sensitive Drosophila mutant, shibire, synaptic vesicles are completely depleted in nerve terminals after stimulation at 34 degrees C, but upon returning to 22 degrees C, endocytosis resumes. In this study, synaptic vesicles in the boutons of nerve terminals at the mutant neuromuscular junction were loaded with a fluorescent dye, FM1-43, during vesicle reformation at 22 degrees C after complete depletion at 34 degrees C. We found two distinct pools of synaptic vesicles, namely an exo/endo cycling pool, located in the periphery of the bouton, and a reserve pool, located in its center. Cytochalasin D treatment eliminated the reserve pool and reduced synaptic transmission evoked by high frequency stimulation. Thus, the reserve pool may play a crucial role for sustaining high frequency synaptic transmission.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Actins / physiology
-
Animals
-
Antineoplastic Agents / pharmacology
-
Colchicine / pharmacology
-
Cytochalasin D / pharmacology
-
Drosophila melanogaster / genetics*
-
Drosophila melanogaster / metabolism
-
Fluorescent Dyes / pharmacokinetics
-
Larva / genetics
-
Larva / metabolism
-
Mutation / physiology
-
Nocodazole / pharmacology
-
Nucleic Acid Synthesis Inhibitors / pharmacology
-
Presynaptic Terminals / chemistry
-
Presynaptic Terminals / drug effects
-
Presynaptic Terminals / physiology*
-
Pyridinium Compounds / pharmacokinetics
-
Quaternary Ammonium Compounds / pharmacokinetics
-
Synaptic Transmission / drug effects
-
Synaptic Transmission / physiology
-
Synaptic Vesicles / drug effects
-
Synaptic Vesicles / metabolism*
-
Temperature
-
Time Factors
Substances
-
Actins
-
Antineoplastic Agents
-
FM1 43
-
Fluorescent Dyes
-
Nucleic Acid Synthesis Inhibitors
-
Pyridinium Compounds
-
Quaternary Ammonium Compounds
-
Cytochalasin D
-
Nocodazole
-
Colchicine