Annexin vi modulates ca2+ and k+ conductances of spinal cord and
dorsal root ganglion neurons.
Naciff, Jorge M., Michael M. Behbehani, Marcia A. Kaetzel, and John R.
Dedman.
Department of Molecular and Cellular Physiology, University of
Cincinnati College of Medicine, Cincinnati, Ohio 45267-0576.
APStracts 3:0228C, 1996.
Annexin VI is a member of a Ca2+-dependent phospholipid-binding
protein family which participates in the transduction of the
intracellular Ca2+-signal. We have identified annexin VI as one of
the major annexins expressed differentially by sensory neurons of
dorsal root ganglia (DRG), and by neurons of the spinal cord (SC) of
the rat and the mouse. This annexin shows a preferential localization
at the plasma membrane of the soma and cellular processes,
particularly in motor neurons of the SC. This finding suggests an
active role of annexin VI in the Ca2+-dependent regulation of plasma
membrane functions. To test this possibility, the neuronal function
of annexin VI was evaluated by whole-cell electrophysiology of mouse
embryo SC and DRG neurons. An antibody was developed which has the
property of neutralizing annexin VI-phospholipid interactions. The
intracellular perfusion of individual neurons in culture, either from
SC or DRG, with monospecific affinity-purified anti-annexin VI
antibodies resulted in an increase in the magnitude of the K+
-current, and in an increase in the Ca2+-current in sensory neurons.
Our results suggest that the endogenous annexin VI regulates the
Ca2+-conductance which indirectly modifies Ca2+-dependent ionic
-conductances in SC and DRG neurons.
Received 17 May 1996; accepted in final form 26 June 1996.
APS Manuscript Number C271-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996