scholarly journals Exercise‐induced muscle chemoreflex modulation of spontaneous baroreflex sensitivity in man

2001 ◽  
Vol 536 (3) ◽  
pp. 957-962 ◽  
Author(s):  
C. A. Carrington ◽  
M. J. White
Author(s):  
René D. Rötzer ◽  
Verena F. Brox ◽  
Konstantin Hennis ◽  
Stefan B. Thalhammer ◽  
Martin Biel ◽  
...  

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Geisa C Tezini ◽  
Silvia Guatimosim ◽  
Diogo A Guimarães ◽  
Mauro Oliveira ◽  
Rubens Fazan ◽  
...  

It was recently developed a transgenic animal model with overexpression of cholinergic neurotransmission. This mouse, named ChAT-ChR2-EYFP, has several extra copies of the vesicular acetylcholine transporter (VAChT) gene and exhibits three-fold increase in the release of acetylcholine. However, the consequences of overexpression of VAChT protein to the cardiovascular system have not yet been characterized. Therefore, we have investigated the effects of the overexpression of the gene of VAChT on arterial pressure (AP) and heart rate (HR) as well as the autonomic cardiovascular regulation. Mice were assigned into two groups: Wild-type (WT, n=7) and ChAT-ChR2-EYFP (n=7). These animals were anesthetized (isoflurane) and implanted with probes to record AP by telemetry. After 10 days, the mice had basal AP and HR recorded continuously. Assessment of the autonomic function was conducted throughout the following approaches: 1) cardiac sympathovagal balance evaluated by HR responses to methylatropine and propranolol; 2) overall HR variability; 3) spontaneous baroreflex sensitivity by the sequence analysis. ChAT-ChR2-EYFP mice showed lower basal HR (461±8 vs. 502±14 bpm, p<0.01) but similar AP as compared to WT mice. ChAT-ChR2-EYFP mice exhibited higher vagal tone (Δbpm, 169±14 vs. 117±6, p=0.03) and lower HR after double autonomic blockade (IHR, 456±8 vs. 509±11 bpm, p<0.001). HR variability was similar between groups (SDNN: 88±16 vs. 65±7 ms; RMSSD: 11.4±1 vs. 9.7±0.5 ms). However, the baroreflex sensitivity (7.5±1.5 vs. 4.1±0.5 ms/mmHg, p=0.05) was higher in ChAT-ChR2-EYFP mice. Altogether, the results show that the cardiovascular autonomic regulation of ChAT-ChR2-EYFP mice is characterized by higher parasympathetic tone, combined with a lower basal HR and IHR. Moreover, these mice present greater baroreflex sensitivity.


2013 ◽  
Vol 23 (4) ◽  
pp. 209-213 ◽  
Author(s):  
Peter Latchman ◽  
Gregory Gates ◽  
Robert Axtell ◽  
Jason Pereira ◽  
Matthew Bartels ◽  
...  

2008 ◽  
Vol 294 (1) ◽  
pp. H474-H480 ◽  
Author(s):  
Cara M. Hildreth ◽  
James R. Padley ◽  
Paul M. Pilowsky ◽  
Ann K. Goodchild

Serotonin (5-HT) is crucial to normal reflex vagal modulation of heart rate (HR). Reduced baroreflex sensitivity [spontaneous baroreflex sensitivity (sBRS)] and HR variability (HRV) reflect impaired neural, particularly vagal, control of HR and are independently associated with depression. In conscious, telemetered Flinders-Sensitive Line (FSL) rats, a well-validated animal model of depression, we tested the hypothesis that cardiovascular regulatory abnormalities are present and associated with deficient serotonergic control of reflex cardiovagal function. In FSL rats and control Flinders-Resistant (FRL) and Sprague-Dawley (SD) rat strains, diurnal measurements of HR, arterial pressure (AP), activity, sBRS, and HRV were made. All strains had normal and similar diurnal variations in HR, AP, and activity. In FRL rats, HR was elevated, contributing to the reduced HRV and sBRS in this strain. In FSL rats, sBRS and high-frequency power HRV were reduced during the night, indicating reduced reflex cardiovagal activity. The ratio of low- to high-frequency bands of HRV was increased in FSL rats, suggesting a relative predominance of cardiac sympathetic and/or reflex activity compared with FRL and SD rats. These data show that conscious FSL rats have cardiovascular regulatory abnormalities similar to depressed humans. Acute changes in HR, AP, temperature, and sBRS in response to 8-hydroxy-2-(di- n-propylamino)tetralin, a 5-HT1A, 5-HT1B, and 5-HT7 receptor agonist, were also determined. In FSL rats, despite inducing an exaggerated hypothermic effect, 8-hydroxy-2-(di- n-propylamino)tetralin did not decrease HR and AP or improve sBRS, suggesting impaired serotonergic neural control of cardiovagal activity. These data suggest that impaired serotonergic control of cardiac reflex function could be one mechanism linking reduced sBRS to increased cardiac risk in depression.


2002 ◽  
Vol 100 (1-2) ◽  
pp. 66-76 ◽  
Author(s):  
Marc-Antoine Custaud ◽  
Edmundo Pereira de Souza Neto ◽  
Patrice Abry ◽  
Patrick Flandrin ◽  
Catherine Millet ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document