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Effect of Pregnancy on Sympathetic and Peripheral Vascular Responses to the Cold Pressor Test
Author(s) -
Wakefield Paige,
Usselman Charlotte,
Stickland Michael,
Chari Radha,
Julian Colleen,
Davenport Margie,
Steinback Craig
Publication year - 2015
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.29.1_supplement.1053.5
Subject(s) - microneurography , neurovascular bundle , cold pressor test , medicine , blood pressure , hemodynamics , vascular resistance , orthostatic intolerance , anesthesia , endocrinology , cardiology , baroreflex , anatomy , orthostatic vital signs , heart rate
Little is known regarding sympathetic neurovascular regulation during pregnancy. We hypothesized that, despite elevated muscle sympathetic nerve activity (MSNA; peroneal microneurography) in normotensive pregnant women (NP) versus non‐pregnant controls (CT), neurovascular transduction would be blunted in NP, resulting in similar mean arterial pressure (MAP) between groups. Integrated MSNA was obtained during 3 min of rest and 3 min of reflex sympathetic activation (cold pressor test; CPT). Total peripheral resistance (TPR; MAP/Q) and burst frequency (BF) were used to calculate neurovascular transduction (TPR/BF). CPT data were analyzed in 30s bins; the bin corresponding to the highest BF value was selected for analysis. Baseline MAP and TPR were not different between NP vs CT (90±16 vs 90±5 mmHg, P =0.9 and 12±2 vs 13±2 mmHg/L/min, P =0.5, respectively) whereas BF (36±7 vs 24±2, P <0.01) and total MSNA (BF x normalized burst amplitude; 1743±286 vs 1145±191, P <0.01) were higher and neurovascular transduction lower (0.3±0.1 vs 0.5±0.1, P =0.01) in NP. During CPT, BF and total MSNA were higher in NP vs CT (56±17 vs 34±10, P =0.03; 2677±650 vs 1529±515, P =0.01), while no differences in MAP or TPR were observed between NP vs CT (99±24 vs 101±7, P =0.8; 13±4 vs 13±3, P =0.7). Neurovascular transduction during CPT was lower in NP than CT (0.24±0.10 vs 0.40±0.07, P =0.01), indicating a vascular adaptation to pregnancy. Supported by WCHRI, NSERC & University of Alberta Human Performance Scholarship Fund.