Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice

Rubens Fazan Jr; Mauro de Oliveira; Valdo José Dias da Silva; Luis Fernando Joaquim; Nicola Montano; Alberto Porta; Mark W Chapleau; Helio C Salgado

doi:10.1152/ajpheart.01224.2004

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Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice

Journal article

Peer reviewed

Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice

Rubens Fazan Jr, Mauro de Oliveira, Valdo José Dias da Silva, Luis Fernando Joaquim, Nicola Montano, Alberto Porta, Mark W Chapleau and Helio C Salgado

American journal of physiology. Heart and circulatory physiology, Vol.289(5), pp.H1968-1975

11/2005

DOI: 10.1152/ajpheart.01224.2004

PMID: 15951338

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Abstract

The goal of this study was to determine the baroreflex influence on systolic arterial pressure (SAP) and pulse interval (PI) variability in conscious mice. SAP and PI were measured in C57Bl/6J mice subjected to sinoaortic deafferentation (SAD, n = 21) or sham surgery (n = 20). Average SAP and PI did not differ in SAD or control mice. In contrast, SAP variance was enhanced (21 +/- 4 vs. 9.5 +/- 1 mmHg2) and PI variance reduced (8.8 +/- 2 vs. 26 +/- 6 ms2) in SAD vs. control mice. High-frequency (HF: 1-5 Hz) SAP variability quantified by spectral analysis was greater in SAD (8.5 +/- 2.0 mmHg2) compared with control (2.5 +/- 0.2 mmHg2) mice, whereas low-frequency (LF: 0.1-1 Hz) SAP variability did not differ between the groups. Conversely, LF PI variability was markedly reduced in SAD mice (0.5 +/- 0.1 vs. 10.8 +/- 3.4 ms2). LF oscillations in SAP and PI were coherent in control mice (coherence = 0.68 +/- 0.05), with changes in SAP leading changes in PI (phase = -1.41 +/- 0.06 radians), but were not coherent in SAD mice (coherence = 0.08 +/- 0.03). Blockade of parasympathetic drive with atropine decreased average PI, PI variance, and LF and HF PI variability in control (n = 10) but had no effect in SAD (n = 6) mice. In control mice, blockade of sympathetic cardiac receptors with propranolol increased average PI and decreased PI variance and LF PI variability (n = 6). In SAD mice, propranolol increased average PI (n = 6). In conclusion, baroreflex modulation of PI contributes to LF, but not HF PI variability, and is mediated by both sympathetic and parasympathetic drives in conscious mice.

Cell Differentiation

Sinoatrial Node - physiology

Mice, Inbred C57BL

Atropine Derivatives - pharmacology

Male

Adrenergic beta-Antagonists - pharmacology

Propranolol - pharmacology

Animals

Receptors, Muscarinic - drug effects

Muscarinic Antagonists - pharmacology

Heart Rate - physiology

Baroreflex - physiology

Mice

Denervation

Details

Title: Subtitle: Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice
Creators: Rubens Fazan Jr - Dept. of Physiology, School of Medicine of Ribeirão Preto-USP, 14049-900 Ribeirão Preto, SP, Brazil. rfazanjr@rfi.fmrp.usp.br
Mauro de Oliveira
Valdo José Dias da Silva
Luis Fernando Joaquim
Nicola Montano
Alberto Porta
Mark W Chapleau
Helio C Salgado
Resource Type: Journal article
Publication Details: American journal of physiology. Heart and circulatory physiology, Vol.289(5), pp.H1968-1975
Publisher: United States
DOI: 10.1152/ajpheart.01224.2004
PMID: 15951338
ISSN: 0363-6135
eISSN: 1522-1539
Language: English
Date published: 11/2005
Academic Unit: Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine
Record Identifier: 9984025569702771

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