|
|
||||||||
Journal of Applied Physiology, Vol 77, Issue 3 1164-1171, Copyright © 1994 by American Physiological Society
ARTICLES |
S. P. Leitch and D. J. Patterson
University Laboratory of Physiology, Oxford, United Kingdom.
Intense exercise can double arterial K+ concentration, decrease pH by 0.4 units, and increase catecholamines 15-fold. Any one of these changes may be cardiotoxic in a subject at rest, yet these changes are well tolerated in exercise. We tested the interactive effects of extracellular K+ concentration ([K+]o), metabolic acidosis (pH 7.0), and raised catecholamines in the isolated working rabbit heart when they were changed with similar kinetics and concentrations to those seen in exercise. Raised [K+]o (8 and 12 mM) significantly decreased aortic flow (AF) by 23 and 76%, respectively (P < 0.01). Acidosis decreased AF by 19% (P < 0.05) and by 38% in combination with 8 mM [K+]o (P < 0.05), making their combined effect additive. Either epinephrine (80 nM), norepinephrine (80 nM) or extracellular Ca2+ concentration (5 mM) offset the negative effects of 8 and 12 mM [K+]o on AF. Norepinephrine also improved AF in 8 mM [K+]o with acidosis. Thus, there may be a beneficial interaction among changes in K+, catecholamines, and acidosis during exercise such that each could offset the others' potentially harmful effects.
This article has been cited by other articles:
![]() |
J. M. Handy and N. Soni Physiological effects of hyperchloraemia and acidosis Br. J. Anaesth., August 1, 2008; 101(2): 141 - 150. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. M. Sejersted and G. Sjogaard Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise Physiol Rev, October 1, 2000; 80(4): 1411 - 1481. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Hogan, B. Casadei, and D. J. Paterson Nitric oxide donors can increase heart rate independent of autonomic activation J Appl Physiol, July 1, 1999; 87(1): 97 - 103. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |