Related Experiment Video
Updated: Jun 22, 2026

Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice
Published on: February 14, 2021
Interaction of cardiac and muscle mechanical afferents on baroreflex control of the sinus node during dynamic
1Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge, Middlesex, UK. luigi.vorluni@brunel.ac.uk
Abstract:
The effects of cardiopulmonary baroreceptors and muscle mechanoreceptors stimulation on cardiac baroreflex sensitivity (BRS), and heart rate variability (HRV) were evaluated by measuring continuously and non-invasively systolic blood pressure (SBP) and pulse interval (PI) during upright and supine passive cycling. BRS and HRV were evaluated with the cross-correlation method (xBRS) and in the frequency domain, respectively. At rest, the shift from upright to supine posture enhanced xBRS from 16.4+/-12.1 to 23.4+/-12.9 ms/mmHg, and the high frequency (HF, 0.15-0.4 Hz) power of HRV from 48.9+/-18.6 to 55.1+/-14.7 normalized units (NU), while it attenuated the low-frequency (LF, 0.04-0.15 Hz) power from 51.1+/-18.6 to 44.9+/-14.7 NU (P<0.05), respectively. During both upright and supine passive exercise, xBRS and the HF power were attenuated (10.0+/-8.0 and 12.5+/-9.0 ms/mmHg; 41.1+/-21.2 and 41.5+/-12.7 NU, respectively; P<0.05) and the LF power increased (58.8+/-21.2 and 58.5+/-12.7 NU, P<0.05), compared with rest. The effect of mechanoreflex activation overrides that of the cardiopulmonary baroreceptors loading resulting in decreased cardiac vagal outflow and reduced BRS during supine passive exercise.
Related Concept Videos
Neural Regulation of Blood Pressure
Baroreceptor Reflex
Baroreceptors, located in the carotid sinuses and aortic arch, detect changes in blood pressure. When blood pressure rises, these stretch-sensitive receptors...
Regulation of the Cardiovascular System
The regulation of the cardiovascular system involves the autonomic nervous system (ANS), baroreceptors, and chemoreceptors, ensuring that heart rate and blood pressure are appropriately modulated in response to varying physiological demands.
The ANS comprises two main divisions: the sympathetic and parasympathetic nervous systems. The sympathetic nervous system enhances...
Regulation of Heart Rates
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
Pathophysiology of Cardiac Performance
Conduction System of the Heart
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
Conduction System of the Heart
This system relies on the unique properties of nodal and Purkinje cells:...

