scholarly journals β-Adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and nonburned skin under neutral and hot environments in children

2017 ◽  
Vol 24 (4) ◽  
pp. e12350 ◽  
Author(s):  
Eric Rivas ◽  
Serina J. McEntire ◽  
David N. Herndon ◽  
Ronald P. Mlcak ◽  
Oscar E. Suman
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Adrenergic Blockade ◽  
Flow Sensitivity ◽  
Hot Environments

scholarly journals Minimal role for H1 and H2 histamine receptors in cutaneous thermal hyperemia to local heating in humans

2006 ◽  
Vol 100 (2) ◽  
pp. 535-540 ◽  
Author(s):  
Brett J. Wong ◽  
Sarah J. Williams ◽  
Christopher T. Minson
Keyword(s):  
Blood Flow ◽  
Receptor Antagonist ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Histamine Receptor ◽  
Receptor Activation ◽  
Control Site ◽  
Doppler Flowmetry ◽  
Histamine Receptor Antagonist ◽  
And Control

The precise mechanism(s) underlying the thermal hyperemic response to local heating of human skin are not fully understood. The purpose of this study was to investigate a potential role for H1 and H2 histamine-receptor activation in this response. Two groups of six subjects participated in two separate protocols and were instrumented with three microdialysis fibers on the ventral forearm. In both protocols, sites were randomly assigned to receive one of three treatments. In protocol 1, sites received 1) 500 μM pyrilamine maleate (H1-receptor antagonist), 2) 10 mM l-NAME to inhibit nitric oxide synthase, and 3) 500 μM pyrilamine with 10 mM NG-nitro-l-arginine methyl ester (l-NAME). In protocol 2, sites received 1) 2 mM cimetidine (H2 antagonist), 2) 10 mM l-NAME, and 3) 2 mM cimetidine with 10 mM l-NAME. A fourth site served as a control site (no microdialysis fiber). Skin sites were locally heated from a baseline of 33 to 42°C at a rate of 0.5°C/5 s, and skin blood flow was monitored using laser-Doppler flowmetry (LDF). Cutaneous vascular conductance was calculated as LDF/mean arterial pressure. To normalize skin blood flow to maximal vasodilation, microdialysis sites were perfused with 28 mM sodium nitroprusside, and control sites were heated to 43°C. In both H1 and H2 antagonist studies, no differences in initial peak or secondary plateau phase were observed between control and histamine-receptor antagonist only sites or between l-NAME and l-NAME with histamine receptor antagonist. There were no differences in nadir response between l-NAME and l-NAME with histamine-receptor antagonist. However, the nadir response in H1 antagonist sites was significantly reduced compared with control sites, but there was no effect of H2 antagonist on the nadir response. These data suggest only a modest role for H1-receptor activation in the cutaneous response to local heating as evidenced by a diminished nadir response and no role for H2-receptor activation.

scholarly journals Effects of mode of exercise recovery on thermoregulatory and cardiovascular responses

2002 ◽  
Vol 93 (6) ◽  
pp. 1918-1924 ◽  
Author(s):  
Robert Carter ◽  
Thad E. Wilson ◽  
Donald E. Watenpaugh ◽  
Michael L. Smith ◽  
Craig G. Crandall
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Heat Dissipation ◽  
Sweat Rate ◽  
Local Heating ◽  
Cardiovascular Responses ◽  
Maximal Heart Rate ◽  
Exercise Recovery ◽  
Active Recovery ◽  
Arterial Blood

To identify the effects of exercise recovery mode on cutaneous vascular conductance (CVC) and sweat rate, eight healthy adults performed two 15-min bouts of upright cycle ergometry at 60% of maximal heart rate followed by either inactive or active (loadless pedaling) recovery. An index of CVC was calculated from the ratio of laser-Doppler flux to mean arterial pressure. CVC was then expressed as a percentage of maximum (%max) as determined from local heating. At 3 min postexercise, CVC was greater during active recovery (chest: 40 ± 3, forearm: 48 ± 3%max) compared with during inactive recovery (chest: 21 ± 2, forearm: 25 ± 4%max); all P < 0.05. Moreover, at the same time point sweat rate was greater during active recovery (chest: 0.47 ± 0.10, forearm: 0.46 ± 0.10 mg · cm−2 · min−1) compared with during inactive recovery (chest: 0.28 ± 0.10, forearm: 0.14 ± 0.20 mg · cm−2 · min−1); all P < 0.05. Mean arterial blood pressure, esophageal temperature, and skin temperature were not different between recovery modes. These data suggest that skin blood flow and sweat rate during recovery from exercise may be modulated by nonthermoregulatory mechanisms and that sustained elevations in skin blood flow and sweat rate during mild active recovery may be important for postexertional heat dissipation.

The effect of local heating on blood flow in the finger and the forearm skin

1987 ◽  
Vol 65 (6) ◽  
pp. 1329-1332 ◽  
Author(s):  
Tetsuo Nagasaka ◽  
Kozo Hirata ◽  
Tadahiro Nunomura ◽  
Michel Cabanac
Keyword(s):  
Blood Flow ◽  
Relative Humidity ◽  
Local Heating ◽  
Venous Occlusion ◽  
Water Bath ◽  
Strain Gauges ◽  
Forearm Skin ◽  
Thermal Sweating ◽  
Hot Environments ◽  
Male Subjects

Blood flow of the finger and the forearm were measured in five male subjects by venous occlusion plethysmography using mercury-in-Silastic strain gauges in either a cool–dry (COOL: 25 °C, 40% relative humidity), a hot–dry (WARM: 35 °C, 40% relative humidity), or a hot–wet (HOT: 35 °C, 80% relative humidity) environment. One hand or forearm was immersed in a water bath, the temperature (Tw) of which was raised every 10 min by steps of 2 °C until it reached 41° or 43 °C. While the other hand or forearm was kept immersed in a water bath (Tw, 35 °C), blood flow in the heated side (BFw) was compared with the corresponding blood flow in the control side (BFc). Under WARM or HOT conditions, linger BFw was significantly lower than finger BFc at a Tw of 39–41 °C in the majority of subjects. When Tw was raised to 43 °C, however, finger BFw became higher than BFc in nearly half of the subjects. In the COOL state, finger BFw did not decrease but increased steadily when Tw increased from 37° to 43 °C. In the forearm, BFw increased steadily with increasing Tw even in WARM–HOT environments. No such heat-induced vasoconstriction was observed in the forearm. From these results we conclude that in hyperthermic subjects, the rise in local temperature to above the core temperature produces vasoconstriction in the fingers, an area where no thermal sweating takes place.

Effect of functional electrostimulation on impaired skin vasodilator responses to local heating in spinal cord injury

2009 ◽  
Vol 106 (4) ◽  
pp. 1065-1071 ◽  
Author(s):  
Noortje T. L. Van Duijnhoven ◽  
Thomas W. J. Janssen ◽  
Daniel J. Green ◽  
Christopher T. Minson ◽  
Maria T. E. Hopman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Axon Reflex ◽  
Doppler Flowmetry ◽  
Cord Injury ◽  
Cutaneous Vascular Conductance ◽  
Functional Electrostimulation

Spinal cord injury (SCI) induces vascular adaptations below the level of the lesion, such as impaired cutaneous vasodilation. However, the mechanisms underlying these differences are unclear. The aim of this study is to examine arm and leg cutaneous vascular conductance (CVC) responses to local heating in 17 able-bodied controls (39 ± 13 yr) and 18 SCI subjects (42 ± 8 yr). SCI subjects were counterbalanced for functional electrostimulation (FES) cycling exercise (SCI-EX, n = 9) or control (SCI-C, n = 9) and reanalyzed after 8 wk. Arm and leg skin blood flow were measured by laser-Doppler flowmetry during local heating (42°C), resulting in an axon-reflex mediated first peak, nadir, and a primarily nitric oxide-dependent plateau phase. Data were expressed as a percentage of maximal CVC (44°C). CVC responses to local heating in the paralyzed leg, but also in the forearm of SCI subjects, were lower than in able-bodied controls ( P < 0.05 and 0.01, respectively). The 8-wk intervention did not change forearm and leg CVC responses to local heating in SCI-C and SCI-EX, but increased femoral artery diameter in SCI-EX ( P < 0.05). Interestingly, findings in skin microvessels contrast with conduit arteries, where physical (in)activity contributes to adaptations in SCI. The lower CVC responses in the paralyzed legs might suggest a role for inactivity in SCI, but the presence of impaired CVC responses in the normally active forearm suggests other mechanisms. This is supported by a lack of adaptation in skin microcirculation after FES cycle training. This might relate to the less frequent and smaller magnitude of skin blood flow responses to heat stimuli, compared with controls, than physical inactivity per se.

Cutaneous vascular responses to isometric handgrip exercise during local heating and hyperthermia

2005 ◽  
Vol 98 (6) ◽  
pp. 2011-2018 ◽  
Author(s):  
Gregg R. McCord ◽  
Christopher T. Minson
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Skin Blood Flow ◽  
Sweat Rate ◽  
Local Heating ◽  
Whole Body ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Hyperthermic Condition ◽  
Isometric Handgrip Exercise

The dramatic increase in skin blood flow and sweating observed during heat stress is mediated by poorly understood sympathetic cholinergic mechanisms. One theory suggests that a single sympathetic cholinergic nerve mediates cutaneous active vasodilation (AVD) and sweating via cotransmission of separate neurotransmitters, because AVD and sweating track temporally and directionally when activated during passive whole body heat stress. It has also been suggested that these responses are regulated independently, because cutaneous vascular conductance (CVC) has been shown to decrease, whereas sweat rate increases, during combined hyperthermia and isometric handgrip exercise. We tested the hypothesis that CVC decreases during isometric handgrip exercise if skin blood flow is elevated using local heating to levels similar to that induced by pronounced hyperthermia but that this does not occur at lower levels of skin blood flow. Subjects performed isometric handgrip exercise as CVC was elevated at selected sites to varying levels by local heating (which is independent of AVD) in thermoneutral and hyperthermic conditions. During thermoneutral isometric handgrip exercise, CVC decreased at sites in which blood flow was significantly elevated before exercise (−6.5 ± 1.8% of maximal CVC at 41°C and −10.5 ± 2.0% of maximal CVC at 43°C; P < 0.05 vs. preexercise). During isometric handgrip exercise in the hyperthermic condition, an observed decrease in CVC was associated with the level of CVC before exercise. Taken together, these findings argue against withdrawal of AVD to explain the decrease in CVC observed during isometric handgrip exercise in hyperthermic conditions.

scholarly journals Augmented supraorbital skin sympathetic nerve activity responses to symptom trigger events in rosacea patients

2015 ◽  
Vol 114 (3) ◽  
pp. 1530-1537 ◽  
Author(s):  
Kristen Metzler-Wilson ◽  
Kumika Toma ◽  
Dawn L. Sammons ◽  
Sarah Mann ◽  
Andrew J. Jurovcik ◽  
...  
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Skin Blood Flow ◽  
Water Loss ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Local Heating ◽  
Nerve Activity ◽  
Axon Reflex ◽  
Trigger Events

Facial flushing in rosacea is often induced by trigger events. However, trigger causation mechanisms are currently unclear. This study tested the central hypothesis that rosacea causes sympathetic and axon reflex-mediated alterations resulting in trigger-induced symptomatology. Twenty rosacea patients and age/sex-matched controls participated in one or a combination of symptom triggering stressors. In protocol 1, forehead skin sympathetic nerve activity (SSNA; supraorbital microneurography) was measured during sympathoexcitatory mental (2-min serial subtraction of novel numbers) and physical (2-min isometric handgrip) stress. In protocol 2, forehead skin blood flow (laser-Doppler flowmetry) and transepithelial water loss/sweat rate (capacitance hygrometry) were measured during sympathoexcitatory heat stress (whole body heating by perfusing 50°C water through a tube-lined suit). In protocol 3, cheek, forehead, forearm, and palm skin blood flow were measured during nonpainful local heating to induce axon reflex vasodilation. Heart rate (HR) and mean arterial pressure (MAP) were recorded via finger photoplethysmography to calculate cutaneous vascular conductance (CVC; flux·100/MAP). Higher patient transepithelial water loss was observed (rosacea 0.20 ± 0.02 vs. control 0.10 ± 0.01 mg·cm−2·min−1, P < 0.05). HR and MAP changes were not different between groups during sympathoexcitatory stressors or local heating. SSNA during early mental (32 ± 9 and 9 ± 4% increase) and physical (25 ± 4 and 5 ± 1% increase, rosacea and controls, respectively) stress was augmented in rosacea (both P < 0.05). Heat stress induced more rapid sweating and cutaneous vasodilation onset in rosacea compared with controls. No axon reflex vasodilation differences were observed between groups. These data indicate that rosacea affects SSNA and that hyperresponsiveness to trigger events appears to have a sympathetic component.

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.

scholarly journals Cutaneous vasomotor responses in boys and men

2018 ◽  
Vol 43 (10) ◽  
pp. 1019-1026 ◽  
Author(s):  
Gary J. Hodges ◽  
Matthew C. Mueller ◽  
Stephen S. Cheung ◽  
Bareket Falk
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Local Skin ◽  
Doppler Flowmetry ◽  
Age Related ◽  
Isometric Handgrip Exercise ◽  
Underlying Mechanisms

Few studies have investigated skin blood flow in children and age-related differences in the underlying mechanisms. We examined mechanisms of skin blood flow responses to local heating, postocclusive reactive hyperaemia (PORH), and isometric handgrip exercise in adult and prepubescent males, hypothesizing that skin blood flow responses would be greater in children compared with adults. We measured skin blood flow in 12 boys (age, 9 ± 1 years) and 12 men (age, 21 ± 1 years) using laser-Doppler flowmetry at rest, in response to 3-min PORH, 2-min isometric handgrip exercise, and local skin heating to 39 °C (submaximal) and 44 °C (maximal). Using wavelet analysis we assessed endothelial, neural, and myogenic activities. At rest and in response to local heating to 39 °C, children had higher skin blood flow and endothelial activity compared with men (d ≥ 1.1, p < 0.001) and similar neurogenic and myogenic activities (d < 0.2, p > 0.05). Maximal responses to 44 °C local skin heating, PORH, and isometric handgrip exercise did not differ between boys and men (all d ≤ 0.2, p > 0.05). During PORH children demonstrated greater endothelial activity compared with men (d ≥ 0.6, p < 0.05); in contrast, men had higher neurogenic activity (d = 1.0, p < 0.01). During isometric handgrip exercise there were no differences in endothelial, neurogenic, and myogenic activities (d < 0.2, p > 0.3), with boys and men demonstrating similar increases in endothelial activity and decreases in myogenic activity (d ≥ 0.8, p < 0.05). These data suggest that boys experience greater levels of skin blood flow at rest and in response to submaximal local heating compared with men, while maximal responses appear to be similar. Additionally, endothelial mediators seem to contribute more to vasodilatation in boys than in men.

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