Permeability changes induced by electric impulses in vesicular membranes
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Electric impulses were found to cause transient permeability changes in the membranes of vesicles storing biogenic amines. Release of catecholamines induced by electric fields (of the order of 20 kV/cm and decaying exponentially with a decay time of about 150 μsec) was studied, using the chromaffin granules of bovine adrenomedullary cells as a vesicular model system. Far-UV-absorption spectroscopy was applied to determine the amount of catecholamines released from suspended vesicles. A polarization mechanism is suggested for the induction of short-lived permeability changes caused by electric fields. Such transient changes in permeability may possibly represent a part of the sequence of events leading to stimulated neurohumoral secretion.
KeywordsHuman Physiology Catecholamine Decay Time Biogenic Amine Permeability Change
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