Affiliation:
1. Department of Physiology, Institute of Health Sciences, Hiroshima University Faculty of Medicine, Hiroshima 734-8551, Japan
Abstract
To examine whether the central characteristics of the aortic baroreflex alter from moment to moment during static exercise, we identified the dynamic changes in the sizes of the bradycardia and depressor response evoked by stimulation of the aortic depressor nerve (ADN). Three conscious cats were trained to voluntarily extend the right forelimb and press a bar for 31 ± 1 s with a peak force of 337 ± 22 g while maintaining a sitting posture. The ADN stimulation-induced bradycardia was attenuated at the initial period of exercise (up to 8 s from the exercise onset) to 62 ± 5% of the preexercise bradycardia and remained blunted until the end of exercise. The most blunted bradycardia was observed immediately before or when the forelimb was extended before force development. The baroreflex-induced bradycardia was suppressed again at cessation of exercise when the forelimb was retracted and recovered within a few seconds. In contrast, static exercise did not affect the ADN stimulation-induced depressor response. The ADN stimulation-induced bradycardia was also blunted at the beginning of naturally occurring body movement such as spontaneous postural change or grooming behavior. Thus it is likely that the central characteristics of the aortic baroreflex dynamically change from moment to moment during voluntary static exercise and during natural body movement and that particularly a central inhibition of the cardiac component of the aortic baroreflex is induced by central command at the onset of static exercise, whereas the central property of the vasomotor component of the baroreflex is preserved.
Publisher
American Physiological Society
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine,Physiology
Reference50 articles.
1. Differential Control of Blood Pressure and Heart Rate by Carotid and Aortic Baroreceptors in Unanaesthetized Cats
2. Circulatory effects of stimulating the carotid arterial stretch receptors in man at rest and during exercise.
3. Bristow JD, Brown EB Jr, Cunningham DJC, Howson MG, Strange Petersen E, Pickering TG, and Sleight P. Effect of bicycling on the baroreflex regulation of pulse interval. Circ Res 38: 582–592, 1971.
4. Coleridge JCG and Coleridge HM. Chemoreflex regulation of the heart. In: Handbook of Physiology. The Cardiovascular System. The Heart. Bethesda, MD: Am. Physiol. Soc, 1979, sect. 2, vol. 1, chapt. 18, p. 653–676.
5. Differential effect of behavior on cardiac and vasomotor baroreflex responses
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