Enhanced cardiopulmonary reflex inhibition of heart rate during exercise.

Title

Enhanced cardiopulmonary reflex inhibition of heart rate during exercise.

Creator

Chen C Y; DiCarlo S E; Collins H L

Publisher

Medicine and science in sports and exercise

Date

1995
1995-10

Description

We tested the hypothesis that the reflex inhibition of heart rate (HR) during mechanical (acute bolus injection of 0.5% and 2% of estimated blood volume) and chemical (phenylbiguanide, PBG, 2.5 and 5 micrograms.kg-1) stimulation of cardiopulmonary receptors would be enhanced during exercise. Rats were instrumented with arterial and venous catheters. The reflex response to mechanical (N = 7) and chemical (N = 8) stimulation of cardiopulmonary receptors was examined at rest and during exercise (6 m.min-1, 10% grade). A two-way analysis of covariance (ANCOVA) with repeated measures was used to test for differences in the reflex regulation of HR at rest vs exercise. HR was used as the covariate because exercise significantly increased baseline HR. There was no significant treatment effect (rest vs exercise) for the reflex inhibition of HR during mechanical stimulation. However, the two-way ANCOVA revealed a significant treatment effect (rest vs exercise) for the reflex inhibition of HR during chemical stimulation. The reflex decreases in HR were enhanced (-delta 23 +/- 8 vs -delta 133 +/- 47 and -delta 208 +/- 40 vs -delta 374 +/- 10 bpm at 2.5 and 5 micrograms.kg-1, respectively). These data suggest that factors associated with exercise enhanced the cardiopulmonary reflex inhibition of heart rate during chemical stimulation.

Subject

Animals; Rats; Analysis of Variance; Physical Stimulation; Blood Pressure/drug effects/physiology; Rest; Biguanides/pharmacology; Blood Volume; Bradycardia/physiopathology; Heart Rate/drug effects/*physiology; Heart/drug effects/*physiology; Hypoglycemic Agents/pharmacology; Lung/drug effects/*physiology; Physical Exertion/*physiology; Reflex/drug effects/*physiology; Sympathetic Nervous System/drug effects/physiology; Vagotomy; Vagus Nerve/drug effects/physiology; Neurons; Chemical; Stimulation; Afferent/drug effects/physiology

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

1399–1405

Issue

10

Volume

27

Citation

Chen C Y; DiCarlo S E; Collins H L, “Enhanced cardiopulmonary reflex inhibition of heart rate during exercise.,” NEOMED Bibliography Database, accessed September 28, 2021, https://neomed.omeka.net/items/show/4913.

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