Relative roles of local and reflex components in cutaneous vasoconstriction during skin cooling in humans

2006 ◽  
Vol 100 (6) ◽  
pp. 2083-2088 ◽  
Author(s):  
Guy E. Alvarez ◽  
Kun Zhao ◽  
Wojciech A. Kosiba ◽  
John M. Johnson
Keyword(s):  
Reflex Response ◽  
Whole Body ◽  
Local Cooling ◽  
Doppler Flowmetry ◽  
Peltier Cooler ◽  
Vasoconstrictor Response ◽  
Skin Cooling ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Independent Effects

The reduction in skin blood flow (SkBF) with cold exposure is partly due to the reflex vasoconstrictor response from whole body cooling (WBC) and partly to the direct effects of local cooling (LC). Although these have been examined independently, little is known regarding their roles when acting together, as occurs in environmental cooling. We tested the hypothesis that the vasoconstrictor response to combined LC and WBC would be additive, i.e., would equal the sum of their independent effects. We further hypothesized that LC would attenuate the reflex vasoconstrictor response to WBC. We studied 16 (7 women, 9 men) young (30.5 ± 2 yr) healthy volunteers. LC and WBC were accomplished with metal Peltier cooler-heater probe holders and water-perfused suits, respectively. Forearm SkBF was monitored by laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated as LDF/blood pressure. Subjects underwent 15 min of LC alone or 15 min of WBC with and without simultaneous LC, either at equal levels (34–31°C) or as equipotent stimuli (34–28°C LC; 34–31°C WBC). The fall in CVC with combined WBC and LC was greater ( P < 0.05) than for either alone (57.0 ± 5% combined vs. 39.2 ± 6% WBC; 34.4 ± 4% LC) with equipotent cooling, but it was only significantly greater than for LC alone with equal levels of cooling (51.3 ± 8% combined vs. 29.5 ± 4% LC). The sum of the independent effects of WBC and LC was greater than their combined effects (74.9 ± 4 vs. 51.3 ± 8% equal and 73.6 ± 7 vs. 57.0 ± 5% equipotent; P < 0.05). The fall in CVC with WBC at LC sites was reduced compared with control sites (17.6 ± 2 vs. 42.4 ± 8%; P < 0.05). Hence, LC contributes importantly to the reduction in SkBF with body cooling, but also suppresses the reflex response, resulting in a nonadditive effect of these two components.

The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans

2007 ◽  
Vol 293 (5) ◽  
pp. H3187-H3192 ◽  
Author(s):  
Gary J. Hodges ◽  
Wojciech A. Kosiba ◽  
Kun Zhao ◽  
Guy E. Alvarez ◽  
John M. Johnson
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Laser Doppler ◽  
Whole Body ◽  
Local Cooling ◽  
Doppler Flowmetry ◽  
Vasoconstrictor Response ◽  
Body Cooling ◽  
Whole Body Cooling

Previous work showed that local cooling (LC) attenuates the vasoconstrictor response to whole body cooling (WBC). We tested the extent to which this attenuation was due to the decreased baseline skin blood flow following LC. In eight subjects, skin blood flow was assessed using laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was expressed as LDF divided by blood pressure. Subjects were dressed in water-perfused suits to control WBC. Four forearm sites were prepared with microdialysis fibers, local heating/cooling probe holders, and laser-Doppler probes. Three sites were locally cooled from 34 to 28°C, reducing CVC to 45.9 ± 3.9, 42 ± 3.9, and 44.5 ± 4.8% of baseline ( P < 0.05 vs. baseline; P > 0.05 among sites). At two sites, CVC was restored to precooling baseline levels with sodium nitroprusside (SNP) or isoproterenol (Iso), increasing CVC to 106.4 ± 12.4 and 98.9 ± 10.1% of baseline, respectively ( P > 0.05 vs. precooling). Whole body skin temperature, apart from the area of blood flow measurement, was reduced from 34 to 31°C. Relative to the original baseline, CVC decreased ( P < 0.05) by 44.9 ± 2.8 (control), 11.3 ± 2.4 (LC only), 29 ± 3.7 (SNP), and 45.8 ± 8.7% (Iso). The reductions at LC only and SNP sites were less than at control or Iso sites ( P < 0.05); the responses at those latter sites were not different ( P > 0.05), suggesting that the baseline change in CVC with LC is important in the attenuation of reflex vasoconstrictor responses to WBC.

Local ascorbate administration inhibits the adrenergic vasoconstrictor response to local cooling in the human skin

2010 ◽  
Vol 108 (2) ◽  
pp. 328-333 ◽  
Author(s):  
Fumio Yamazaki
Keyword(s):  
Human Skin ◽  
Adrenergic Receptors ◽  
Whole Body ◽  
Antioxidant Supplementation ◽  
Local Cooling ◽  
Vasoconstrictor Response ◽  
Increased Sensitivity ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Β Adrenergic Receptors

Local cooling (LC) of nonglabrous skin causes vasoconstriction via the adrenergic and removal of nitric oxide (NO) systems. Since cooling increases reactive oxygen species in smooth muscle cells and induces increased sensitivity of α-adrenergic receptors, antioxidant supplementation may attenuate the vasoconstrictor response to skin LC via adrenergic and/or NO systems. To test this hypothesis, we examined the effects of acute l-ascorbate (Asc, 10 mM) supplementation in human skin on the vasoconstrictor responses to LC in skin with and without NO synthase (NOS) inhibition or adrenergic receptor blockade. In a three-part study, forearm sites were instrumented with microdialysis fibers, local coolers, and laser-Doppler flow (LDF) probes in healthy volunteers. Sites were cooled from 34 to 24°C at −1°C/min and maintained at 24°C for 20 min ( parts 1 and 2) or 30 min ( part 3). During the last 10 min of LC in parts 1 and 2, whole body cooling was performed to increase sympathetic vasoconstrictor activity. Cutaneous vascular conductance (CVC) was calculated as the ratio of LDF to blood pressure and expressed relative to the baseline value before cooling. Treatments in each part were as follows: part 1) untreated, Asc; part 2) NG-nitro-l-arginine methyl ester (l-NAME) to inhibit NOS, combined l-NAME + Asc; part 3) yohimbine (YOH) + propranolol (PRO) to antagonize α- and β-adrenergic receptors and combined YOH + PRO + Asc. CVC reduction during LC was smaller ( P < 0.001) at Asc sites (−31 ± 4%) than at untreated sites (−56 ± 5%). LC-induced reduction in CVC was smaller ( P < 0.05) at l-NAME + Asc sites (−23 ± 8%) than at l-NAME sites (−43 ± 7%). LC-induced reduction in CVC did not differ between at PRO + YOH sites (−56 ± 3%) and at PRO + YOH + Asc sites (−50 ± 3%). These findings suggest that antioxidant supplementation inhibits the vasoconstrictor response to direct cooling through an adrenoceptor-dependent mechanism in human skin.

scholarly journals The nitric oxide dependence of cutaneous microvascular function to independent and combined hypoxic cold exposure

2020 ◽  
Vol 129 (4) ◽  
pp. 947-956
Author(s):  
Josh T. Arnold ◽  
Alex B. Lloyd ◽  
Stephen J. Bailey ◽  
Tomomi Fujimoto ◽  
Ryoko Matsutake ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Nitrite Reduction ◽  
Whole Body ◽  
Local Cooling ◽  
Cutaneous Reflex ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Oxide Removal ◽  
Oxide Synthase

When separated from local cooling, whole body cooling elicited cutaneous reflex vasoconstriction via mechanisms independent of nitric oxide removal. Hypoxia elicited cutaneous vasodilatation via mechanisms mediated primarily by nitric oxide synthase, rather than xanthine oxidase-mediated nitrite reduction. Cold-induced vasoconstriction was blunted by the opposing effect of hypoxic vasodilatation, whereas the underpinning mechanisms did not interrelate in the absence of local cooling. Full vasoconstriction was restored with nitric oxide synthase inhibition.

scholarly journals Oral sapropterin augments reflex vasoconstriction in aged human skin through noradrenergic mechanisms

2013 ◽  
Vol 115 (7) ◽  
pp. 1025-1031 ◽  
Author(s):  
Anna E. Stanhewicz ◽  
Lacy M. Alexander ◽  
W. Larry Kenney
Keyword(s):  
Human Skin ◽  
Venous Blood ◽  
Placebo Treatment ◽  
Whole Body ◽  
Double Blind ◽  
Doppler Flowmetry ◽  
Adrenergic Mechanisms ◽  
Aged Skin ◽  
Body Cooling ◽  
Whole Body Cooling

Reflex vasoconstriction is attenuated in aged skin due to a functional loss of adrenergic vasoconstriction. Bioavailability of tetrahydrobiopterin (BH4), an essential cofactor for catecholamine synthesis, is reduced with aging. Locally administered BH4 increases vasoconstriction through adrenergic mechanisms in aged human skin. We hypothesized that oral sapropterin (Kuvan, a pharmaceutical BH4) would augment vasoconstriction elicited by whole-body cooling and tyramine perfusion in aged skin. Ten healthy subjects (age 75 ± 2 yr) ingested sapropterin (10 mg/kg) or placebo in a randomized, double-blind crossover design. Venous blood samples were collected prior to, and 3 h following ingestion. Three intradermal microdialysis fibers were placed in the forearm skin for local delivery of 1) lactated Ringer, 2) 5 mM BH4, and 3) 5 mM yohimbine + 1 mM propranolol (Y+P; to inhibit adrenergic vasoconstriction). Red cell flux was measured at each site by laser-Doppler flowmetry (LDF) as reflex vasoconstriction was induced by lowering and then clamping whole-body skin temperature ( T̄sk) using a water-perfused suit. Following whole-body cooling, subjects were rewarmed and 1 mM tyramine was perfused at each site to elicit endogenous norepinephrine release from the perivascular nerve terminal. Cutaneous vascular conductance was calculated as CVC = LDF/mean arterial pressure and expressed as change from baseline (ΔCVC). Plasma BH4 was elevated 3 h after ingestion of sapropterin (43.8 ± 3 vs. 19.1 ± 2 pmol/ml; P < 0.001). Sapropterin increased reflex vasoconstriction at the Ringer site at T̄sk ≤ 32.5°C ( P < 0.05). Local BH4 perfusion augmented reflex vasoconstriction at T̄sk ≤ 31.5°C with placebo treatment only ( P < 0.05). There was no treatment effect on reflex vasoconstriction at the BH4-perfused or Y+P-perfused sites. Sapropterin increased pharmacologically induced vasoconstriction at the Ringer site (−0.19 ± 0.03 vs. −0.08 ± 0.02 ΔCVC; P = 0.01). There was no difference in pharmacologically induced vasoconstriction between treatments at the BH4-perfused site (−0.16 ± 0.04 vs. −0.14 ± 0.03 ΔCVC; P = 0.60) or the Y+P-perfused site (−0.05 ± 0.02 vs.−0.06 ± 0.02 ΔCVC; P = 0.79). Sapropterin increases both reflex (cold-induced) and pharmacologically induced vasoconstriction through adrenergic mechanisms and may be a viable intervention to improve reflex vasoconstriction in aged humans.

Cutaneous vasoconstrictor response to whole body skin cooling is altered by time of day

2003 ◽  
Vol 94 (3) ◽  
pp. 930-934 ◽  
Author(s):  
Ken Aoki ◽  
Dan P. Stephens ◽  
Adham R. Saad ◽  
John M. Johnson
Keyword(s):  
Cooling Water ◽  
Time Of Day ◽  
Whole Body ◽  
Doppler Flowmetry ◽  
Diurnal Difference ◽  
Vasoconstrictor Response ◽  
Skin Cooling ◽  
A Site ◽  
The Relationship ◽  
Cutaneous Vascular Conductance

To test for a diurnal difference in the vasoconstrictor control of the cutaneous circulation, we performed whole body skin cooling (water-perfused suits) at 0600 (AM) and 1600 (PM). After whole body skin temperature (Tsk) was controlled at 35°C for 10 min, it was progressively lowered to 32°C over 18–20 min. Skin blood flow (SkBF) was monitored by laser-Doppler flowmetry at three control sites and at a site that had been pretreated with bretylium by iontophoresis to block noradrenergic vasoconstriction. After whole body skin cooling, maximal cutaneous vascular conductance (CVC) was measured by locally warming the sites of SkBF measurement to 42°C for 30 min. Before whole body skin cooling, sublingual temperature (Tor) in the PM was significantly higher than that in the AM ( P < 0.05), but CVC, expressed as a percentage of maximal CVC (%CVCmax), was not statistically different between AM and PM. During whole body skin cooling, %CVCmax levels at bretylium-treated sites in AM or PM were not significantly reduced from baseline. In the PM, %CVCmax at control sites fell significantly at Tsk of 34.3 ± 0.01°C and lower ( P< 0.05). In contrast, in the AM %CVCmax at control sites was not significantly reduced from baseline until Tskreached 32.3 ± 0.01°C and lower ( P < 0.05). Furthermore, the decrease in %CVCmax in the PM was significantly greater than that in AM at Tsk of 33.3 ± 0.01°C and lower ( P < 0.05). Integrative analysis of the CVC response with respect to both Tor and Tsk showed that the cutaneous vasoconstrictor response was shifted to higher internal temperatures in the PM. These findings suggest that during whole body skin cooling the reflex control of the cutaneous vasoconstrictor system is shifted to a higher internal temperature in the PM. Furthermore, the slope of the relationship between CVC and Tsk is steeper in the PM compared with that in the AM.

Effects of fitness, fatness, and age on men's responses to whole body cooling in air

1991 ◽  
Vol 71 (6) ◽  
pp. 2387-2393 ◽  
Author(s):  
G. M. Budd ◽  
J. R. Brotherhood ◽  
A. L. Hendrie ◽  
S. E. Jeffery
Keyword(s):  
Multiple Regression ◽  
Skinfold Thickness ◽  
Fat Free Mass ◽  
Whole Body ◽  
Skin Fold Thickness ◽  
Skin Fold ◽  
Vasoconstrictor Response ◽  
Tissue Insulation ◽  
Body Cooling ◽  
Whole Body Cooling

Simple and multiple regression analyses were used to assess the influence of 12 white men's fitness (aerobic capacity 44–58 ml O2.min-1.kg fat-free mass-1), fatness (mean skin-fold thickness 5–20 mm, body fat content 15–36%), and age (26–52 yr) on their thermal, metabolic, cardiovascular, and subjective responses to 2 h of whole body cooling, nude, in air at 10 degrees C. Fitter men had slower heart rates, and fatter men had higher blood pressures. Fitness had no effect (P greater than 0.39) on any measured response to cold. Fatness was associated (P less than 0.01) with reduced heat loss, heat production, and mean skin temperature; unchanged heat debt; and increased tissue insulation. Age had the opposite effects. When the confounding effects of fatness were held constant by multiple regression, older men responded to cold as though they were 1 mm of skinfold thickness leaner for each 3–4 yr of age. We conclude that aging, even between the relatively youthful ages of 26 and 52 yr, is accompanied by a progressive weakening of the vasoconstrictor response to cold.

scholarly journals Reproducibility of Whole‐Body Cooling Response Using Laser Doppler Flowmetry

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Kelsey S. Schwartz ◽  
Behnia R. Shirazi ◽  
James A. Lang
Keyword(s):  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Whole Body ◽  
Doppler Flowmetry ◽  
Body Cooling ◽  
Whole Body Cooling

scholarly journals Methods for personal cooling in hot environment used in clothing and wearables

2021 ◽  
Vol 327 ◽  
pp. 03003
Author(s):  
Atanas Vasilev ◽  
Radostina A. Angelova ◽  
Rositsa Velichkova
Keyword(s):  
Phase Change Materials ◽  
Cooling System ◽  
Cooling Water ◽  
Whole Body ◽  
Health Issues ◽  
Local Cooling ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Hot Environments ◽  
Personal Cooling

The use of an efficient personal cooling system in hot environments is becoming increasingly popular, as the increased air temperature provokes thermophysiological discomfort, heat stress, reduced productivity and could lead to several health issues. Different methods and devices for personal and local cooling have been developed over the years. The paper summarises the cooling methods applied in clothing and wearable items: phase-change materials, Peltier elements, evaporative cooling, water cooling and hybrid cooling. The local vs total (of the whole body) cooling is examined. The passive and active colling are analysed in terms of advantages, disadvantages and application.

scholarly journals Reflex vasoconstriction in aged human skin increasingly relies on Rho kinase-dependent mechanisms during whole body cooling

2009 ◽  
Vol 297 (5) ◽  
pp. H1792-H1797 ◽  
Author(s):  
James A. Lang ◽  
John D. Jennings ◽  
Lacy A. Holowatz ◽  
W. Larry Kenney
Keyword(s):  
Age Groups ◽  
Rho Kinase ◽  
Ringer Solution ◽  
Control Site ◽  
Whole Body ◽  
Doppler Flowmetry ◽  
Nos Inhibitors ◽  
Aged Skin ◽  
Body Cooling ◽  
Whole Body Cooling

Primary human aging may be associated with augmented Rho kinase (ROCK)-mediated contraction of vascular smooth muscle and ROCK-mediated inhibition of nitric oxide synthase (NOS). We hypothesized that the contribution of ROCK to reflex vasoconstriction (VC) is greater in aged skin. Cutaneous VC was elicited by 1) whole body cooling [mean skin temperature (Tsk) = 30.5°C] and 2) local norepinephrine (NE) infusion (1 × 10−6 M). Four microdialysis fibers were placed in the forearm skin of eight young (Y) and eight older (O) subjects for infusion of 1) Ringer solution (control), 2) 3 mM fasudil (ROCK inhibition), 3) 20 mM NG-nitro-l-arginine methyl ester (NOS inhibition), and 4) both ROCK + NOS inhibitors. Red cell flux was measured by laser-Doppler flowmetry over each site. Cutaneous vascular conductance (CVC) was calculated as flux/mean arterial pressure and normalized to baseline CVC (%ΔCVCbaseline). VC was reduced at the control site in O during cooling (Y, −34 ± 3; and O, −18 ± 3%ΔCVCbaseline; P < 0.001) and NE infusion (Y, −53 ± 4, and O, −41 ± 9%ΔCVCbaseline; P = 0.006). Fasudil attenuated VC in both age groups during mild cooling; however, this reduction remained only in O but not in Y skin during moderate cooling (Y, −30 ± 5; and O, −7 ± 1%ΔCVCbaseline; P = 0.016) and was not altered by NOS inhibition. Fasudil blunted NE-mediated VC in both age groups (Y, −23 ± 4; and O, −7 ± 3%ΔCVCbaseline; P < 0.01). Cumulatively, these data indicate that reflex VC is more reliant on ROCK in aged skin such that approximately half of the total VC response to whole body cooling is ROCK dependent.

Neuropeptide Y antagonism reduces reflex cutaneous vasoconstriction in humans

2004 ◽  
Vol 287 (3) ◽  
pp. H1404-H1409 ◽  
Author(s):  
Dan P. Stephens ◽  
Adham R. Saad ◽  
Lee Ann T. Bennett ◽  
Wojciech A. Kosiba ◽  
John M. Johnson
Keyword(s):  
Neuropeptide Y ◽  
Ringer Solution ◽  
Whole Body ◽  
Doppler Flowmetry ◽  
Arterial Blood ◽  
Npy Receptor ◽  
Series Of Experiments ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Cutaneous Vasoconstriction

Previous studies have provided evidence of a non-noradrenergic contributor to reflex cutaneous vasoconstriction in humans but did not identify the transmitter responsible. To test whether neuropeptide Y (NPY) has a role, in two series of experiments we slowly reduced whole body skin temperature (TSK) from 34.5 to 31.7°C. In protocol 1, Ringer solution and the NPY receptor antagonist BIBP-3226 alone were delivered intradermally via microdialysis. In protocol 2, yohimbine plus propranolol (Yoh + Pro), Yoh + Pro in combination with BIBP-3226, and Ringer solution were delivered to antagonize locally the vasomotor effects of NPY and norepinephrine. Blood flow was measured by laser Doppler flowmetry (LDF). Mean arterial blood pressure (MAP) was monitored at the finger (Finapres). In protocol 1, cutaneous vascular conductance (CVC) fell by 45%, to 55.1 ± 5.6% of baseline at control sites ( P < 0.05). At BIBP-3226-treated sites, CVC fell by 34.1% to 65.9 ± 5.0% ( P < 0.05; P < 0.05 between sites). In protocol 2, during body cooling, CVC at control sites fell by 32.6%, to 67.4 ± 4.3% of baseline; at sites treated with Yoh + Pro, CVC fell by 18.7%, to 81.3 ± 4.4% of baseline ( P < 0.05 vs. baseline; P < 0.05 vs. control) and did not fall significantly at sites treated with BIBP-3226 + Yoh + Pro ( P > 0.05; P < 0.05 vs. other sites). After cooling, exogenous norepinephrine induced vasoconstriction at control sites ( P < 0.05) but not at sites treated with Yoh + Pro + BIBP-3226 ( P > 0.05). These results indicate that NPY participates in sympathetically mediated cutaneous vasoconstriction in humans during whole body cooling.

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