title: Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans.
abstract: Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n = 13). The O&S increased limb circumference, MSNA burst rate (arm: Δ6.7 ± 0.7; leg: Δ6.8 ± 0.7 bursts/min), and total activity (arm: Δ199 ± 14; leg: Δ172 ± 22 units/min) and BP (arm: Δ4.3 ± 0.3; leg: Δ9.4 ± 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r = 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans.
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Blaha
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Herr
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Rachel C
authors.identifier: http://orcid.org/0000-0001-8001-1946
authors.initials: RC
authors.lastname: Drew
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors.forename: Matthew D
authors.identifier: http://orcid.org/0000-0002-7411-8816
authors.initials: MD
authors.lastname: Muller
authors.affiliation: Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania lsinoway@hmc.psu.edu.
authors.forename: Lawrence I
authors.initials: LI
authors.lastname: Sinoway
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001158:Arteries / Q000294:innervation*; D001794:Blood Pressure; D003251:Constriction, Pathologic; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007262:Infusions, Intravenous; D007866:Leg / Q000098:blood supply*; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation*; D011312:Pressure; D012018:Reflex; D012039:Regional Blood Flow; D012965:Sodium Chloride / Q000008:administration & dosage; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013997:Time Factors; D014111:Tourniquets; D014680:Veins / Q000294:innervation
chemical_list: D012965:Sodium Chloride
keywords: autonomic; blood pressure regulation; vessel