|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Internal Medicine and 2 Department of Pharmacology, University of California, Davis, California 95616; and 3 Discipline of Human Physiology and Hunter Heart-Lung Research Guild, University of Newcastle, Callaghan, New South Wales 2308, Australia
In hypertensive subjects, a single bout of dynamic exercise results in an immediate lowering of blood pressure back toward normal. This postexercise hypotension (PEH) also occurs in the spontaneously hypertensive rat (SHR). In both humans and SHRs, PEH features a decrease in sympathetic nerve discharge, suggesting the involvement of central nervous system pathways. Given that substance P is released in the nucleus tractus solitarius (NTS) by activation of baroreceptor and skeletal muscle afferent fibers during muscle contraction, we hypothesized that substance P acting at neurokinin-1 (NK-1) receptors in the NTS might contribute to PEH. We tested the hypothesis by determining, in conscious SHRs, whether NTS microinjections of the NK-1 receptor antagonist SR-140333 before exercise attenuated PEH. The antagonist, in a dose (60 pmol) that blocked substance P- and spared D,L-homocysteic acid-induced depressor responses, significantly attenuated the PEH by 37%, whereas it had no effect on blood pressure during exercise. Vehicle microinjection had no effect. The antagonist also had no effect on heart rate responses during both exercise and the PEH period. The data suggest that a substance P (NK-1) receptor mechanism in the NTS contributes to PEH.
NK-1 receptor; exercise; microinjection; blood pressure; hypertension; nucleus tractus solitarius
This article has been cited by other articles:
![]() |
D. S. Kimmerly, S. W. Wong, D. Salzer, R. Menon, and J. K. Shoemaker Forebrain regions associated with postexercise differences in autonomic and cardiovascular function during baroreceptor unloading Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H299 - H306. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. P. Joad, P. A. Munch, J. M. Bric, S. J. Evans, K. E. Pinkerton, C.-Y. Chen, and A. C. Bonham Passive Smoke Effects on Cough and Airways in Young Guinea Pigs: Role of Brainstem Substance P Am. J. Respir. Crit. Care Med., February 15, 2004; 169(4): 499 - 504. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. W. Williamson, R. McColl, and D. Mathews Changes in regional cerebral blood flow distribution during postexercise hypotension in humans J Appl Physiol, February 1, 2004; 96(2): 719 - 724. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. L. Abdala, A. S. Haibara, and E. Colombari Cardiovascular responses to substance P in the nucleus tractus solitarii: microinjection study in conscious rats Am J Physiol Heart Circ Physiol, July 11, 2003; 285(2): H891 - H898. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. L. Barnes, D. M. DeWeese, and M. C. Andresen Angiotensin potentiates excitatory sensory synaptic transmission to medial solitary tract nucleus neurons Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2003; 284(5): R1340 - R1353. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |