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Effects of aging and coronary artery disease on sympathetic neural recruitment strategies during end-inspiratory and end-expiratory apnea
- Source :
- Bone and Joint Institute, Kinesiology Publications
- Publication Year :
- 2016
- Publisher :
- American Physiological Society, 2016.
-
Abstract
- In response to acute physiological stress, the sympathetic nervous system modifies neural outflow through increased firing frequency of lower-threshold axons, recruitment of latent subpopulations of higher-threshold axons, and/or acute modifications of synaptic delays. Aging and coronary artery disease (CAD) often modify efferent muscle sympathetic nerve activity (MSNA). Therefore, we investigated whether CAD ( n = 14; 61 ± 10 yr) and/or healthy aging without CAD (OH; n = 14; 59 ± 9 yr) modified these recruitment strategies that normally are observed in young healthy (YH; n = 14; 25 ± 3 yr) individuals. MSNA (microneurography) was measured at baseline and during maximal voluntary end-inspiratory (EI) and end-expiratory (EE) apneas. Action potential (AP) patterns were studied using a novel AP analysis technique. AP frequency increased in all groups during both EI- and EE-apnea (all P < 0.05). The mean AP content per integrated burst increased during EI- and EE-apnea in YH (EI: Δ6 ± 4 APs/burst; EE: Δ10 ± 6 APs/burst; both P < 0.01) and OH (EI: Δ3 ± 3 APs/burst; EE: Δ4 ± 5 APs/burst; both P < 0.01), but not in CAD (EI: Δ1 ± 3 APs/burst; EE: Δ2 ± 3 APs/burst; both P = NS). When APs were binned into “clusters” according to peak-to-peak amplitude, total clusters increased during EI- and EE-apnea in YH (EI: Δ5 ± 2; EE: Δ6 ± 4; both P < 0.01), during EI-apnea only in OH (EI: Δ1 ± 2; P < 0.01; EE: Δ1 ± 2; P = NS), and neither apnea in CAD (EI: Δ −2 ± 2; EE: Δ −1 ± 2; both P = NS). In all groups, the AP cluster size-latency profile was shifted downwards for every corresponding cluster during EI- and EE-apnea (all P < 0.01). As such, inherent dysregulation exists within the central features of apnea-related sympathetic outflow in aging and CAD.
- Subjects :
- Male
Aging
Sympathetic nervous system
Sympathetic Nervous System
Apnea
Physiology
Action Potentials
Blood Pressure
Coronary Artery Disease
Disease
030204 cardiovascular system & hematology
Coronary artery disease
Neural recruitment
Breath Holding
0302 clinical medicine
Medicine and Health Sciences
Cardiac Output
Age Factors
Middle Aged
Kinesiology
Plethysmography
medicine.anatomical_structure
Inhalation
Exhalation
Sympathetic neural recruitment patterns
Cardiology
Female
medicine.symptom
Cardiology and Cardiovascular Medicine
Adult
medicine.medical_specialty
Efferent Pathways
Young Adult
03 medical and health sciences
Physiology (medical)
Internal medicine
medicine
Humans
Arterial Pressure
Muscle, Skeletal
Aged
business.industry
Stroke Volume
medicine.disease
Endocrinology
Case-Control Studies
Vascular Resistance
business
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 15221539 and 03636135
- Volume :
- 311
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Heart and Circulatory Physiology
- Accession number :
- edsair.doi.dedup.....67e38905811619b999defd5bfcb7605b