The influence of circulating angiotensin ii and vasopressin on
neurons of the nucleus of the solitary tract.
Hegarty, Allison A., Linda F. Hayward, and Robert B. Felder.
Cardiovascular Center and Department of Internal Medicine,
University of Iowa College of Medicine, Iowa City, IA 52242
APStracts 2:0295R, 1995.
The central cardiovascular effects of the circulating peptides
angiotensin II (ANGII) and arginine vasopressin (AVP) may be mediated
through the nucleus of the solitary tract (NTS). In this study, we
used single unit extracellular recording techniques to determine the
effects of peripheral infusions of ANGII and AVP on NTS neurons.
Baro-sensitive NTS neurons were characterized by their response to an
increase in arterial pressure induced with phenylephrine (PE). 17/74
NTS neurons were excited by ANGII infusion. Of these, 9 were also
excited by activation of baroreceptors. 15/74 neurons were inhibited
by ANGII, 13 of which were also baro-inhibited. 13/77 NTS neurons
were excited by AVP infusion. 7/13 were also baro-excited. One AVP
-excited neuron was inhibited by a PE-induced increase in arterial
pressure. 21/77 neurons were inhibited by AVP, 10 of which were also
baro-inhibited. 2/21 AVP-inhibited neurons were excited by an
increase in arterial pressure. These results indicate that some baro
-sensitive NTS neurons may be independently influenced by circulating
peptides and that separate populations of baro-sensitive and peptide
-sensitive neurons are found in the NTS.
Received 28 June 1995; accepted in final form 20 October 1995.
APS Manuscript Number R402-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 November 95