European Journal of Applied Physiology
Postsynaptic cutaneous vasodilation and sweating: inﬂuence
of adiposity and hydration status
Matthew A. Tucker
· Aaron R. Caldwell
· Cory L. Butts
· Forrest B. Robinson
· Stavros A. Kavouras
Brendon P. McDermott
· Tyrone A. Washington
· Ronna C. Turner
· Matthew S. Ganio
Received: 5 February 2018 / Accepted: 24 May 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Introduction Obesity and hypohydration independently aﬀect postsynaptic endothelial function, but it is unknown if hypo-
hydration aﬀects lean and obese individuals diﬀerently.
Purpose To examine the eﬀect of hypohydration on postsynaptic cutaneous vasodilation and sweating in men with high and
low adiposity (HI- and LO-BF, respectively).
Methods Ten males with LO-BF and ten with HI-BF were instrumented for forearm microdialysis when euhydrated and
hypohydrated. Changes in cutaneous vascular conductance (CVC) with intradermal infusion of sodium nitroprusside (SNP)
and methacholine chloride (MCh) were assessed. Local sweat rate (LSR) was simultaneously assessed at the MCh site.
At the end of the last dose, maximal CVC was elicited by delivering a maximal dose of SNP for 30 min to both sites with
simultaneous local heating at the SNP site. The concentration of drug needed to elicit 50% of the maximal response (EC
was compared between groups and hydration conditions.
Results When euhydrated, EC
of MCh-induced CVC was not diﬀerent between LO- vs. HI-BF [− 3.04 ± 0.12 vs.
− 2.98 ± 0.19 log (MCh) M, P = 0.841]. EC
of SNP-induced CVC was higher in euhydrated HI- vs. LO-BF (− 1.74 ± 0.17
vs. − 2.13 ± 0.06 log (SNP) M, P = 0.034). Within each group, hydration status did not change MCh- or SNP-induced CVC
(P > 0.05). LSR was not diﬀerent between groups or hydration condition (P > 0.05).
Conclusions These data suggest reduced sensitivity of endothelium-independent vasodilation in individuals with high adipos-
ity when euhydrated. However, hypohydration does not aﬀect cutaneous vasodilation or local sweat rate diﬀerently between
individuals with low or high adiposity.
Keywords Microvascular dysfunction · Skin blood ﬂow · Thermoregulation · Dehydration
BF Body fat
CNS Central nervous system
CVC Cutaneous vascular conductance
DXA Dual-energy X-ray absorptiometry
EDHF Endothelial-derived hyperpolarizing factor
HI-BF High adiposity
LO-BF Low adiposity
LSR Local sweat rate
MAP Mean arterial pressure
MCh Methacholine chloride
NO Nitric oxide
SkBF Skin blood ﬂow
SNP Sodium nitroprusside
Communicated by Narihiko Kondo.
* Matthew S. Ganio
Department of Health, Human Performance, and Recreation,
University of Arkansas, HPER 321-E, 155 Stadium Dr.,
Fayetteville, AR 72701, USA
Georgia Prevention Institute, Augusta University, Augusta,
Department of Rehabilitation, Human Resources,
and Communication Disorders, University of Arkansas,
Fayetteville, AR, USA