Mechanosensitive Currents in Putative Aortic Baroreceptor Neurons In
Vitro.
Cunningham, J. Thomas , Ruth E. Wachtel, and Francois M. Abboud (with
technical assistance from Laurie J. Waite and Shane Kraske).
Departments of Internal Medicine and Anesthesia and the Cardiovascular
Center, College of Medicine, University of Iowa, Iowa City 52242; and and the
Department of Veterans Affairs Medical Center, Iowa City, Iowa 52246.
APStracts 2:0059N, 1995.
SUMMARY AND CONCLUSIONS
1 . Whole cell patch-clamp experiments were conducted to determine whether rat
aortic baroreceptor neurons rat contain mechanosensitive conductances. 2 .
Putative aortic baroreceptor neurons in the nodose ganglia were identified by
injecting DiI<AQ> onto the adventitia of the aortic arch. Nodose ganglia
neurons were dissociated after >/=1 wk. A fluorescein- conjugated tetanus
toxin fragment was used to confirm that the cells labeled with DiI in culture
were neurons. 3 . Hypoosmotic stretch significantly increased the conductance
of DiI-labeled neurons ( n = 19). The reversal potential of the response was
_11 +/- 1 (SE<AQ> mV. 4 . In experiments on unlabeled neurons, only 7 of
13 cells showed increases in conductance. BC3H1 cells, a mouse tumor cell
line, showed no changes in conductance. 5 . Gadolinium (20 mM), a putative
blocker of mechanosensitive channels, prevented the increase in conductance
produced by hypoosmolality in seven of seven labeled cells. Equimolar
concentrations of lanthanum ( n = 6) and _- conotoxin GVIA (1 mM, n = 4),
which block voltage-gated calcium channels, failed to significantly affect
the inward current.
Received 30 November 1994; accepted in final form 6 February 1995.
APS Manuscript Number J745-4.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 3 April 1995.