|
|
||||||||
Zablocki Department of Veterans Affairs Medical Center and Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53295
Evidence suggests that
transmission of barosensitive input from arterial baroreceptors and
cardiac mechanoreceptors at nucleus tractus solitarius (NTS) neurons
involves non-N-methyl-D-aspartate (NMDA)
glutamate receptors, but there is a possibility that the contribution
of NMDA receptors might increase during periods of increased afferent
input, when enhanced neuronal depolarization could increase the
activation of NMDA receptors by removal of a Mg2+ block.
Thus the effects of NMDA on cardiac mechanoreceptor-modulated NTS
neuronal discharges were examined at different levels of arterial pressure used to change cardiac mechanoreceptor afferent input. To
determine whether the response was specific to NMDA,
(±)-
-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) was
also administered at different levels of neuronal discharge. In
anesthetized dogs, neuronal activity was recorded from the NTS while
NMDA or AMPA was picoejected at high versus low arterial stimulating
pressures. NMDA, but not AMPA, produced a significantly greater
discharge of mechanoreceptor-driven NTS neurons at higher versus lower
levels of stimulating pressure. These data suggest that the role played
by NMDA receptors is greater during periods of enhanced neuronal
depolarization, which could be produced by increases in afferent
barosensitive input.
medulla; nucleus tractus solitarius; AMPA; baroreceptors
This article has been cited by other articles:
![]() |
A. C. Bonham, C.-Y. Chen, S.-i. Sekizawa, and J. P. Joad Plasticity in the nucleus tractus solitarius and its influence on lung and airway reflexes J Appl Physiol, July 1, 2006; 101(1): 322 - 327. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. C. R. Dias and E. Colombari Central nitric oxide modulates hindquarter vasodilation elicited by AMPA receptor stimulation in the NTS of conscious rats Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2006; 290(5): R1330 - R1336. [Abstract] [Full Text] [PDF] |
||||
![]() |
C.-Y. Chen and A. C. Bonham Glutamate suppresses GABA release via presynaptic metabotropic glutamate receptors at baroreceptor neurones in rats J. Physiol., January 15, 2005; 562(2): 535 - 551. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Seagard, C. Dean, S. Patel, D. J. Rademacher, F. A. Hopp, W. T. Schmeling, and C. J. Hillard Anandamide content and interaction of endocannabinoid/GABA modulatory effects in the NTS on baroreflex-evoked sympathoinhibition Am J Physiol Heart Circ Physiol, March 1, 2004; 286(3): H992 - H1000. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |