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Role of potassium in the reflex regulation of blood pressure during static exercise in man.
Author(s) -
Fallentin N,
Jensen B R,
Byström S,
Sjøgaard G
Publication year - 1992
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1992.sp019183
Subject(s) - reflex , blood pressure , medicine , cardiology , venous blood , forearm , anesthesia , anatomy
1. The relationship between [K+] in venous effluent blood and alterations in mean arterial blood pressure was studied during static handgrip contractions at 15 and 30% of maximal voluntary contraction (MVC). 2. To further elucidate the importance of K+ in the reflex regulation of blood pressure a situation with normal recovery was compared with a situation in which 3 min of post‐exercise occlusion was applied by arresting the circulation to the forearm just prior to the cessation of the contraction. 3. There was a temporal as well as quantitative correlation between venous [K+] and the blood pressure response during and after static exercise. During 30% MVC mean arterial blood pressure (MAP) attained 161.7 mmHg and venous [K+] 5.8 mM, while the corresponding values during 15% MVC were 121.5 mmHg and 5.0 mM. 4. In the occlusion period mean arterial blood pressure remained elevated above resting level and provided a measure of the magnitude of muscle chemoreflexes. In the same period venous [K+] was maintained at 5.3 mM and 4.6 mM following 30% MVC and 15% MVC respectively. This is indicative of interstitial concentrations of above 8‐10 mM. This level is sufficiently high to stimulate type III and IV muscle afferents involved in the reflex regulation of blood pressure, and strengthens the notion that K+ may play an important role in eliciting the pressor reflex. 5. In contrast to [K+] the time course of venous blood concentrations of lactate and ammonia (NH3) exhibited a clear dissociation from the blood pressure recordings.