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Record Details

Record 29 of 1554
Neural blockade during exercise augments central command's contribution to carotid baroreflex resetting
Author and Affiliation:
Querry, R. G.(Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States)
Smith, S. A.
Stromstad, M.
Ide, K.
Raven, P. B.
Secher, N. H.
Abstract: This investigation was designed to determine central command's role on carotid baroreflex (CBR) resetting during exercise. Nine volunteer subjects performed static and rhythmic handgrip exercise at 30 and 40% maximal voluntary contraction (MVC), respectively, before and after partial axillary neural blockade. Stimulus-response curves were developed using the neck pressure-neck suction technique and a rapid pulse train protocol (+40 to -80 Torr). Regional anesthesia resulted in a significant reduction in MVC. Heart rate (HR) and ratings of perceived exertion (RPE) were used as indexes of central command and were elevated during exercise at control force intensity after induced muscle weakness. The CBR function curves were reset vertically with a minimal lateral shift during control exercise and exhibited a further parallel resetting during exercise with neural blockade. The operating point was progressively reset to coincide with the centering point of the CBR curve. These data suggest that central command was a primary mechanism in the resetting of the CBR during exercise. However, it appeared that central command modulated the carotid-cardiac reflex proportionately more than the carotid-vasomotor reflex.
Publication Date: Apr 01, 2001
Document ID:
20040112526
(Acquired Oct 05, 2004)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Journal Article
Publication Information: American journal of physiology. Heart and circulatory physiology (ISSN 0363-6135); Volume 280; 4; H1635-44
Publisher Information: United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ARTERIES; BAROREFLEXES; BLOOD PRESSURE; CAROTID SINUS BODY; HEART RATE; MUSCULAR FUNCTION; NECK (ANATOMY); PHYSICAL EXERCISE; PHYSICAL WORK; SKELETAL MUSCLE; ADULTS; ANESTHETICS; ELECTROCARDIOGRAPHY; ELECTROPHYSIOLOGY; HAND (ANATOMY); MALES
Other Descriptors: BAROREFLEX/PHYSIOLOGY; BLOOD PRESSURE/PHYSIOLOGY; CAROTID SINUS/DRUG EFFECTS/PHYSIOLOGY; EXERTION/PHYSIOLOGY; HEART RATE/PHYSIOLOGY; ISOMETRIC CONTRACTION/DRUG EFFECTS/PHYSIOLOGY; LIDOCAINE/ADMINISTRATION & DOSAGE/PHARMACOLOGY; MUSCLE, SKELETAL/INNERVATION/PHYSIOLOGY; ADULT; ANESTHETICS, LOCAL/ADMINISTRATION & DOSAGE/PHARMACOLOGY; ELECTROCARDIOGRAPHY; ELECTROPHYSIOLOGY/METHODS; HAND STRENGTH; HUMAN; INFUSIONS, PARENTERAL; MALE; REFERENCE VALUES; SUPPORT, NON-U.S. GOV'T; NASA DISCIPLINE CARDIOPULMONARY; NON-NASA CENTER
Availability Source: Other Sources
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