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Full-Text Articles in Life Sciences
Impact Of Age On Cerebrovascular Dilation Versus Reactivity To Hypercapnia., Nicole S Coverdale, Mark B Badrov, J Kevin Shoemaker
Impact Of Age On Cerebrovascular Dilation Versus Reactivity To Hypercapnia., Nicole S Coverdale, Mark B Badrov, J Kevin Shoemaker
Kinesiology Publications
This study quantified the effect of age on cerebrovascular reactivity and cerebrovascular conductance while accounting for differences in grey matter volume in younger (YA: n = 12; 24 ± 4 years, six females) and older adults (OA: n = 10; 66 ± 7 years; five females). Cerebral blood flow velocity (CBFV; transcranial Doppler) in the middle cerebral artery (MCA), MCA cross-sectional area (CSA), intracranial volumes (magnetic resonance imaging), and mean arterial pressure (MAP; Finometer), were measured under normocapnic and hypercapnic (6% carbon dioxide) conditions. Cerebral blood flow (CBF) was quantified from CBFV and MCA CSA and normalized to grey matter …
Effect Of Age On The Hemodynamic And Sympathetic Responses At The Onset Of Isometric Handgrip Exercise., Sophie Lalande, Carolyn P Sawicki, Jacquie R Baker, Kevin Shoemaker
Effect Of Age On The Hemodynamic And Sympathetic Responses At The Onset Of Isometric Handgrip Exercise., Sophie Lalande, Carolyn P Sawicki, Jacquie R Baker, Kevin Shoemaker
Kinesiology Publications
Cardiac and peripheral vasomotor factors contribute to the rapid pressor response at the onset of isometric handgrip exercise. We tested the hypothesis that age enhances the sympathetic and vasoconstrictor response at the onset of isometric handgrip exercise so that the pressor response is maintained, despite a diminished cardiac function. Twelve young and twelve older (24 ± 3 and 63 ± 8 yr) individuals performed 20-s isometric handgrip exercise at 30, 40, or 50% of maximal voluntary contraction force. Muscle sympathetic nerve activity (MSNA) was measured using microneurography. Mean arterial pressure (MAP) and cardiac output (Q) were assessed continuously by finger …
Neuropeptide Y And Neurovascular Control In Skeletal Muscle And Skin., Gary J Hodges, Dwayne N Jackson, Louis Mattar, John M Johnson, J Kevin Shoemaker
Neuropeptide Y And Neurovascular Control In Skeletal Muscle And Skin., Gary J Hodges, Dwayne N Jackson, Louis Mattar, John M Johnson, J Kevin Shoemaker
Kinesiology Publications
Neuropeptide Y (NPY) is a ubiquitous peptide with multiple effects on energy metabolism, reproduction, neurogenesis, and emotion. In addition, NPY is an important sympathetic neurotransmitter involved in neurovascular regulation. Although early studies suggested that the vasoactive effects of NPY were limited to periods of high stress, there is growing evidence for the involvement of NPY on baseline vasomotor tone and sympathetically evoked vasoconstriction in vivo in both skeletal muscle and the cutaneous circulation. In Sprague-Dawley rat skeletal muscle, Y(1)-receptor activation appears to play an important role in the regulation of basal vascular conductance, and this effect is similar in magnitude …