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Alpha-latrotoxin channels in neuroblastoma cells
W P Hurlbut1, E Chieregatti, F Valtorta
1Bruno Ceccarelli Center, University of Milan, Italy.
The Journal of Membrane Biology
|February 1, 1994
Summary
Alpha-latrotoxin induces novel ion channels in neuroblastoma cells. These channels, permeable to various ions, may explain toxin-induced neurotransmitter release.
Area of Science:
- Neuroscience
- Cell Biology
- Biophysics
Background:
- Alpha-latrotoxin is a potent neurotoxin known to cause massive neurotransmitter release.
- The precise molecular mechanisms underlying alpha-latrotoxin's effects on neuronal cells are not fully understood.
Purpose of the Study:
- To investigate the changes in ionic permeability induced by alpha-latrotoxin in NG108-15 neuroblastoma x glioma cells.
- To characterize the properties of ion channels formed by alpha-latrotoxin.
Main Methods:
- Nystatin perforated-patch technique for whole-cell recording.
- Electrophysiological analysis of single channel activity and ion permeability.
Main Results:
- Complex single channel activity was observed in cell membranes after alpha-latrotoxin application.
- Channels exhibited fluctuating conductance (max ~300 pS), permeable to Na+, K+, Ca2+, and Mg2+, poorly permeable to Cl-.
- Channel activity persisted in various ionic conditions, including low/no divalent cations, and was blocked by La3+.
Conclusions:
- Alpha-latrotoxin induces the formation of novel, multi-conductance ion channels in NG108-15 cells.
- These channels' ion flux properties could account for the massive neurotransmitter release observed in nerve terminals upon alpha-latrotoxin exposure.