Abstract
The role of cGMP-dependent pathways in synaptic vesicle recycling in motor nerve endings during prolonged high-frequency stimulation was studied at frog neuromuscular junctions using electrophysiological and fluorescent methods. An increase of intracellular cGMP concentration (8-Br-cGMP or 8-pCPT-cGMP) significantly reduced the cycle time for synaptic vesicles through the enhancement of vesicular traffic rate from the recycling pool to the readily releasable pool and acceleration of fast endocytosis. Pharmacological inhibition of soluble guanylate cyclase or protein kinase G slowed down the rate of recycling as well as endocytosis of synaptic vesicles. The results suggest that cGMP-PKG-dependent pathway serves a significant function in the control of vesicular cycle in frog motor terminals.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cyclic GMP / metabolism*
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Cyclic GMP-Dependent Protein Kinases / metabolism
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Endocytosis / physiology
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Fluorescent Dyes
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Guanylate Cyclase / metabolism
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Microscopy, Fluorescence
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Motor Neurons / metabolism*
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Motor Neurons / ultrastructure
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Neuromuscular Junction / metabolism*
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Neuromuscular Junction / ultrastructure
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Patch-Clamp Techniques
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Presynaptic Terminals / metabolism*
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Presynaptic Terminals / ultrastructure
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Pyridinium Compounds
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Quaternary Ammonium Compounds
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Rana ridibunda
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Signal Transduction / physiology
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Synaptic Membranes / metabolism
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Synaptic Membranes / ultrastructure
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Synaptic Potentials / physiology
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Synaptic Transmission / physiology*
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Synaptic Vesicles / metabolism*
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Synaptic Vesicles / ultrastructure
Substances
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FM1 43
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Fluorescent Dyes
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Pyridinium Compounds
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Quaternary Ammonium Compounds
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Cyclic GMP-Dependent Protein Kinases
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Guanylate Cyclase
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Cyclic GMP