Premium
Isolated muscle metaboreflex activation enhances arterial baroreflex control of muscle sympathetic nerve activity in older adults
Author(s) -
Greaney Jody L,
Fadel Paul J,
Farquhar William B
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.841.2
Previous studies reported that activation of metabolically‐sensitive muscle afferents (muscle metaboreflex) enhanced the gain of arterial baroreflex control of muscle sympathetic nerve activity (MSNA) in young subjects. It is not known if this neural interaction is present among older adults. To begin to address this question, blood pressure (Finometer) and MSNA (peroneal microneurography) were measured in 8 older subjects (59±1 yrs) at rest and during 2 min of post‐exercise ischemia (PEI) following 40% MVC isometric handgrip to isolate the muscle metaboreflex. Weighted linear regression analysis between MSNA and diastolic blood pressure was used to estimate the gain of arterial baroreflex control of total MSNA and burst incidence. Mean blood pressure was increased significantly from rest to PEI (92±4 to 110±4 mmHg; P<0.01) indicating robust metaboreflex activation. Arterial baroreflex gain for total MSNA (−11.0±1.3 to −15.6±1.5 AU/beat/mmHg; P=0.02) and burst incidence (−4.2±0.8 to −6.5±1.5 bursts/100 heart beats/mmHg; P=0.08) were elevated during PEI. Thus, in older normotensive subjects muscle metaboreflex activation enhanced arterial baroreflex MSNA gain. These preliminary findings suggest that the neural interaction between the arterial baroreflex and muscle metaboreflex in sympathetic control is maintained with age. Supported by NIH Grant HL‐074851 (to W.B.F.) and HL‐093167 (to P.J.F.).