Increase In Peripheral Blood Flow Research Articles

Acute stress and restricted diet reduce bill-mediated heat dissipation in the song sparrow (Melospiza melodia): implications for optimal thermoregulation.

We used thermal imaging to show that two environmental factors - acute stress and diet - influence thermoregulatory performance of a known thermal window, the avian bill. The bill plays important roles in thermoregulation and water balance. Given that heat loss through the bill is adjustable through vasoconstriction and vasodilation, and acute stress can cause vasoconstriction in peripheral body surfaces, we hypothesized that stress may influence the bill's role as a thermal window. We further hypothesized that diet influences heat dissipation from the bill, given that body condition influences the surface temperature of another body region (the eye region). We measured the surface temperature of the bills of song sparrows (Melospiza melodia) before, during and after handling by an observer at 37°C ambient temperature. We fed five birds a restricted diet intended to maintain body mass typical of wild birds, and we fed six birds an unrestricted diet for 5months prior to experiments. Acute stress caused a decrease in the surface temperature of the bill, resulting in a 32.4% decrease in heat dissipation immediately following acute stress, before recovering over approximately 2.3 min. The initial reduction and subsequent recovery provide partial support for the hemoprotective and thermoprotective hypotheses, which predict a reduction or increase in peripheral blood flow, respectively. Birds with unrestricted diets had larger bills and dissipated more heat, indicating that diet and body condition influence bill-mediated heat dissipation and thermoregulation. These results indicate that stress-induced vascular changes and diet can influence mechanisms of heat loss and potentially inhibit optimal thermoregulation.

Evaluation of blood perfusion using laser doppler flowmetry during endoscopic lumbar sympathectomy in patients with plantar hyperhidrosis: a retrospective observational study

The purpose of this study is to evaluate whether monitoring the changes of skin blood flow may be effective in assessing blood perfusion during endoscopic lumbar sympathectomy (ELS) in patients with plantar hyperhidrosis. In this study, a total of 30 patients who underwent surgical treatment for plantar hyperhidrosis at the Department of Thoracic and Cardiovascular Surgery in Yonsei University Gangnam Severance Hospital, Seoul, Korea, between July 2020 and December 2020, were retrospectively analyzed. Sympathetic denervation was performed on the third lumbar ganglion, and intraoperative laser doppler flowmetry (LDF) was used to detect the lumbar sympathetic chain accurately. We observed an abrupt increase of peripheral blood flow after sympathetic denervation, and the median percent changes of perfusion unit were 173.27 (inter-quartile range, IQR 195.48) and 392.98 (IQR 597.27) for the left and right sympathectomies, respectively. This study demonstrated the efficacy of monitoring skin blood flow via LDF during ELS. This result suggests that exact detection of blood flow using LDF is essential for improving the accuracy of ELS by checking the perfusion site on the sole in patients with plantar hyperhidrosis.

5-HT Receptors and Temperature Homeostasis.

The present review summarizes the data concerning the influence of serotonin (5-HT) receptors on body temperature in warm-blooded animals and on processes associated with its maintenance. This review includes the most important part of investigations from the first studies to the latest ones. The established results on the pharmacological activation of 5-HT1A, 5-HT3, 5-HT7 and 5-HT2 receptor types are discussed. Such activation of the first 3 type of receptors causes a decrease in body temperature, whereas the 5-HT2 activation causes its increase. Physiological mechanisms leading to changes in body temperature as a result of 5-HT receptors’ activation are discussed. In case of 5-HT1A receptor, they include an inhibition of shivering and non-shivering thermogenesis, as well simultaneous increase of peripheral blood flow, i.e., the processes of heat production and heat loss. The physiological processes mediated by 5-HT2 receptor are opposite to those of the 5-HT1A receptor. Mechanisms of 5-HT3 and 5-HT7 receptor participation in these processes are yet to be studied in more detail. Some facts indicating that in natural conditions, without pharmacological impact, these 5-HT receptors are important links in the system of temperature homeostasis, are also discussed.

Cardiovascular Drift Response Over Two Different Constant-load Exercises In Healthy Non-athletes. Case Study.

Cardiovascular drift (CV-d) is a steady increase in heart rate (HR) over time while performing constant load moderate intensity exercise (CME) > 20 min. CV-d presents problems for the prescription of exercise intensity by means of HR, because the work rate (WR) during exercise must be adjusted to maintain target HR, thus disturbing the intended effect of the exercise intervention. It has been shown that the increase in HR during CME is due to changes in WR and not to CV-d. PURPOSE: We aimed to investigate whether, indeed, the CV-d in healthy young people exercising at the WR corresponding to the lactate individual anaerobic threshold (IAT) determined in two different cardiorespiratory exercise test (CPT), was related to the WR difference. METHODS: Seven participants (30 ± 3 years old, 1.75 ± 0.1 m., 74.6 ± 12.8 Kg.) performed on different days two CPT with a WR increase of 20 Watts (W) every one or three minutes until exhaustion. The WR corresponding to the IAT was determined during these tests. The participants then performed two CME with a WR corresponding to the IAT. HR and blood lactate (La) were continuously measured during all tests. A comparison between CPTs and CMEs were made using a paired t-test. A one-way ANOVA repeated measurements was used to compare La values during the CME. RESULTS: VO2max (36.9 ± 59 vs. 35.6 ± 5.7 ml·Kg-1·min-1; p > 0.05), maximal HR (181 ± 9 vs. 178 ± 11 bpm; p = 0.3), and peak La (8.7 ± 1.6 vs. 7.8 ± 1.6; p = 0.1) did not differ between CPTs. Maximal power output (271 ± 80 vs. 223 ± 75 W; p < 0.001) and WR at the IAT (164 ± 63 vs. 137 ± 45 W; p > 0.01) were different between CPTs. La between CMEs and minutes 10 and 30 were not different (3 ± 0.4 vs. 3.3 ± 0.5; p = 0.1). One-CME mean HR was 157 ± 12 bpm with an increase of 8 ± 4 bpm between minutes 10-30. Three-MCE HR was 147 ± 14 bpm and the HR increased by 9 ± 7 bpm between minute 10-30. Only a difference in HR between the two CME was found (p = 0.009) whereas there was no difference in the HR change between minute 10-30 (p = 0.7). CONCLUSION: In this case study, the CV-d was not significantly different between the two CMEs (One-IAT and Three-IAT) despite a significant difference in the amount of WR between CMEs (26 ± 19). Other factors aside from the WR like an increase in peripheral blood flow, hyperthermia, plasma volume reduction, catecholamine levels, and training status play a role in the CV-d phenomenon.

Attenuated Mental Stress‐Induced Brachial Artery Hyperemia in Women Relative to Men

While the contributing factors resulting in hypertension and cardiovascular disease (CVD) are multifactorial, vascular dysfunction and exposure to chronic stress are key contributors. In this regard, previous research has indicated that men and women exhibit differential responses to stress. Acute mental stress (MS) elicits increases in peripheral blood flow that are predominately mediated by the actions of nitric oxide (NO) and thus is a technique that can be utilized to assess vascular function. Previous research has focused on sex differences in the response to MS in a variety of physiological variables; however, the impact of sex on the peripheral blood flow response to MS is less clear. Accordingly, the purpose of this study was to investigate the brachial BF hyperemic response during acute MS between men and women. We hypothesized that the hyperemic response to MS would be similar between the groups. Nine women (studied between days 2–7 of the follicular phase of the menstrual cycle) and seventeen men participated in this study. All measurements were obtained in the supine position following a 15 min baseline period. After the baseline period, the left arm was instrumented for continuous assessment of brachial artery diameter and blood velocity, which were used for subsequent calculation of brachial BF. Continuous arterial blood pressure was obtained on the contralateral arm for calculation of forearm vascular conductance (FVC; Flow/MAP). Brachial BF and FVC were continuously calculated during 2 min of baseline and 3 min of MS induced by asking subjects to subtract 7 continuously from a 3‐digit number while attempting to report answers at a pace set by a 60 bpm metronome. Compared to men, women had a reduced baseline blood flow (men: 84.39 ± 49.39 mL/min, women: 36.79 ± 15.41 mL/min; p = 0.01). In response to mental stress, women also had attenuated responses in the following variables: peak BF achieved during MS (men: 244.94 ± 119.06, women: 141.75 ± 86.98 ml/min; p = 0.03), total BF throughout the duration of MS (men: 408.91 ± 131.10, women: 196.84 ± 86.72 ml/min; p &lt; 0.01) and peak FVC achieved during MS (men: 2.86 ± 1.24, women: 1.13 ± 0.63 mL/min/mmHg; p &lt; 0.01). In conclusion, contrary to our hypothesis, these preliminary findings indicate that women had a reduced hyperemic response in the brachial artery during MS relative to men. Further research is warranted to assess mechanisms of these differential responses between sexes.Support or Funding InformationUTA Start‐up funds to R. Matthew BrothersThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Exploration of the Phenomenon of Psychological Time

The phenomenon of psychological time is manifested in its irreducibility of absolute time and is defined as the ability to achieve personal goals. Individual peculiarities of perception and experience of time are the basis of self-organization of human activity. The relevance of an objective study of the significance of the phenomenonof time is determined by the importance of this category for the implementation of the functions of adaptation and self-realization. Psychophysiological methods can be used to estimate the objective value of time in the system of human semantic links. It allows you to evaluate the strength of psychophysiological reactions of aperson. The individual value of the time category can be calculated on the basis of the integral intensity of the reaction force: heart rate, breathing amplitude, increase in the amplitude of the systole (increase in peripheral blood flow), the severity of the high-amplitude positive half-wave (departure of the KGR wave upward from isolation).&#x0D; Keywords: phenomenon of time, objective research methods, psychophysiological acts, the importance of the concept

Affective and autonomic response to dynamic rhythmic entrainment: Mechanisms of a specific music therapy factor

Dynamic rhythmic entrainment, that is the bi-directional synchronization between an internal oscillator and an external musical beat, is frequently used in music therapy to promote psychophysiological relaxation and well-being. However, little is understood about the nature of this mechanism and its link to affective judgments. The objective of this study was to examine specific cardiovascular and affective effects of live music matched with the listener’s heart beat, with the tempo gradually decreased to assess the relaxation effect.Thirty apparently healthy students were randomized to either the experimental (EG) or the control group (CG). After a brief mental stress task, both groups listened to a live music therapy relaxation technique. While a biofeedback device was utilized to enable real-time synchronization of relaxing music to the listener’s pulse in the EG, the tempo in the CG was fixed to 70 beats per minute. Self-ratings of stress and well-being, as well as autonomic measures of cardiovascular reactivity were assessed.The entrained-tempo condition led to a significantly stronger increase in peripheral blood flow (p < .01) and subjective well-being (p = .036). No between-group differences were observed for changes in pulse rate and self-rated stress level (both p > .05).We conclude that rhythmic entrainment may promote a psychophysiological relaxation response. The decrease in sympathetic arousal may have led to more favorable affective self-ratings via an interoceptive feedback process, but more research is needed to clarify the direction of effects.

Femoral vascular conductance and peroneal muscle sympathetic nerve activity responses to acute epidural spinal cord stimulation in humans.

What is the central question of this research? Does acute spinal cord stimulation increase vascular conductance and decrease muscle sympathetic nerve activity in the lower limbs of humans? What is the main finding and its importance? Acute spinal cord stimulation led to a rapid rise in femoral vascular conductance, and peroneal muscle sympathetic nerve activity demonstrated a delayed reduction that was not associated with the initial increase in femoral vascular conductance. These findings suggest that neural mechanisms in addition to attenuated muscle sympathetic nerve activity might be involved in the initial increase in femoral vascular conductance during acute spinal cord stimulation. Clinical cases have indicated an increase in peripheral blood flow after continuous epidural spinal cord stimulation (SCS) and that reduced muscle sympathetic nerve activity (MSNA) might be a potential mechanism. However, no studies in humans have directly examined the effects of acute SCS (<60min) on vascular conductance and MSNA. In study 1, we tested the hypothesis that acute SCS (<60min) of the thoracic spine would lead to increased common femoral vascular conductance, but not brachial vascular conductance, in 11 patients who previously underwent surgical SCS implantation for management of neuropathic pain. Throughout 60min of SCS, common femoral artery conductance was elevated and significantly different from brachial artery conductance [in millilitres per minute: 15min, change (Δ) 26±37 versus Δ-2±19%; 30min, Δ28±45 versus Δ0±26%; 45min, Δ48±43 versus Δ2±21%; 60min, Δ36±61 versus Δ1±24%; and 15min post-SCS, Δ51±64 versus Δ6±33%; P=0.013]. A similar examination in a patient with cervical SCS revealed minimal changes in vascular conductance. In study 2, we examined whether acute SCS reduces peroneal MSNA in a subset of SCS patients (n=5). The MSNA burst incidence in response to acute SCS gradually declined and was significantly reduced at 45 and 60min of SCS (in bursts per 100heart beats: 15min, Δ-1±12%; 30min, Δ-14±12%; 45min, Δ-19±16%; 60min, Δ-24±18%; and 15min post-SCS: Δ-11±7%; P=0.015). These data demonstrate that acute SCS rapidly increases femoral vascular conductance and reduces peroneal MSNA. The gradual reduction in peroneal MSNA observed during acute SCS suggests that neural mechanisms in addition to attenuated MSNA might be involved in the acute increase in femoral vascular conductance.

Heat stress exacerbates the reduction in middle cerebral artery blood velocity during prolonged self-paced exercise.

This study examined the influence of hyperthermia on middle cerebral artery mean blood velocity (MCA Vmean). Eleven cyclists undertook a 750 kJ self-paced time trial in HOT (35 °C) and COOL (20 °C) conditions. Exercise time was longer in HOT (56 min) compared with COOL (49 min; P < 0.001). Power output in HOT was significantly lower from 40% of work completed onward (P < 0.01). Rectal temperature increased to 39.6 ± 0.6 °C (HOT) and 38.8 ± 0.5 °C (COOL; P < 0.01). Skin temperature, skin blood flow, and heart rate were higher throughout HOT compared with COOL (P < 0.05). A similar increase in ventilation (P < 0.05) and decrease in end-tidal partial pressure of CO2 (PETCO2 ; P < 0.05) occurred in both conditions. Arterial blood pressure and oxygen uptake were lower from 50% of work completed onward in HOT compared with COOL (P < 0.01). MCA Vmean increased at 10% in both conditions (P < 0.01), decreasing thereafter (P < 0.01) and to a greater extent in HOT from 40% of work completed onward (P < 0.05). Therefore, despite a comparable ventilatory response and PETCO2 in the HOT and COOL conditions, the greater level of thermal strain developing in the heat appears to have exacerbated the reduction in MCA Vmean, in part via increases in peripheral blood flow and a decrease in arterial blood pressure.

The contribution of cardiac mechanics to isolated increases in peripheral blood flow (1073.4)

The human heart responds to whole‐body increases in cardiovascular demand by enhancing heart rate (HR) and intrinsic cardiac muscle function. However, it is not known if enhanced left ventricular (LV) muscle function ('LV mechanics') also contributes to localized increases in peripheral blood flow and, if so, whether enhanced peripheral blood flow per se or other arterial hemodynamic signals are the mechanism for acutely adjusting LV mechanics. We performed cardiac and vascular ultrasonography in eight healthy individuals (4 women) during 1) Baseline, 2) Bilateral arm heating (BAH), and 3) BAH with partial brachial artery occlusion (BAH+OCC) at mean arterial pressure (MAP, 85±15 mmHg). BAH markedly increased skin temperatures (32.71±0.69 to 39.21±0.60 deg. C, p&lt;0.0001) while rectal core temperature was unaltered (p=0.54). Brachial artery blood flow measured in the left arm increased almost threefold with BAH (98±46 to 266±96 mL/min, P&lt;0.0001) and returned to baseline levels with BAH+OCC. Arterial wave reflection, as assessed by applanation tonometry, had a tendency to increase with BAH and remained elevated with BAH+OCC (p=0.07). Increased cardiac output (p=0.02) was entirely explained by increased HR of 3‐4 bpm (P=0.002). In contrast, LV mechanics ‐ evaluated by systolic longitudinal strain and diastolic untwisting velocity ‐ did not change with BAH but they declined significantly with BAH+OCC (both p&lt;0.05), which was accompanied by a rise in MAP (P&lt;0.0001).In conclusion, the heart contributes to isolated increases in peripheral blood flow by enhancing HR but not its intrinsic LV muscle mechanics. Because LV output was maintained during the period of enhanced blood flow demand and increased afterload (=BAH+OCC), reduced systolic and diastolic LV mechanics during this condition may reflect an intrinsic protection of LV myofibers from pressure stress rather than a decline in LV function.

Exercise on land or in water?

We have read with interest the study published in the International Journal of General Medicine entitled “Hypotensive response after water-walking and land walking exercise sessions in healthy trained and untrained women” by Rodriguez et al.1 In this study, the authors investigated cardiovascular changes induced by walking in water in comparison with walking on land. Water exercises are commonly used in rehabilitation programs, particularly patients with mobility problems. Recently, some studies have suggested that exercise performed in water could improve cardiovascular function.2 Thermoneutral headout water immersion leads to important hemodynamic alterations, such as increases in both cardiac preload and cardiac output and a decrease in peripheral vascular resistance.3 An increase in cardiac output induces an increase in peripheral blood flow and subsequently an increase in endothelial shear stress. This mechanism could be responsible for greater improvement in endothelial function after water gymnastics in comparison with land exercise. Consequently, water exercises might be of particular interest for patients with endothelial dysfunction. However, clinical interest in water exercise for the treatment of cardiovascular disease remains to be established. Further studies are needed to compare the cardiovascular effects of exercises performed in water and on land. We have some concerns about the methods used in the study reported by Rodriguez et al1 whereby all subjects were immersed in a bath and remained standing for 60 minutes before the exercise period. The temperature of the water was adjusted to 30°C ± 1°C. The thermoconductivity of water is 25 times greater than that of air. Consequently, the loss of body heat in water requires that thermal conditions be rigorously controlled. In the study by Rodriguez et al1 the suitability of the water temperature is debatable. Previous studies have determined that for subjects at rest, to provide thermoneutral conditions in water, the temperature of the bath should be maintained between 34°C and 35°C. In exercising volunteers, a thermoneutral water temperature was found to be around 32°C. To accommodate these conditions, some authors have investigated resting volunteers during headout immersion in water at temperatures between 34°C and 35°C. Subsequently, to provide thermoneutral water temperature during exercise, water temperature was progressively cooled to 32.5°C.4,5 These water temperature conditions produced a pulmonary arterial temperature in water similar to that on land at any exertion level from 40% to 100% of maximal oxygen consumption.5 In the work performed by Rodriguez et al the water temperature was below thermoneutrality both at rest and during exercise. It has been documented by Park et al6 that headout water immersion at a temperature below 34°C or 35°C modifies hemodynamic status in comparison with both thermoneutral water immersion and ambient air. During headout water immersion at thermoneutral temperature, cardiac output and stroke volume increased compared with levels in air. At a lower temperature, the increased stroke volume tended to be higher, whereas the heart rate decreased. Furthermore, the decrease in peripheral vascular resistance, commonly observed in thermoneutral water immersion, was attenuated when the temperature was decreased down from 34.5°C to 30°C. Arterial pressure was also altered, and an increase in diastolic arterial pressure was recorded at temperatures lower than 34.5°C. Lastly, it has been demonstrated that autonomic control of the cardiovascular system is variously affected depending on water temperature. During thermoneutral headout water immersion, decreased sympathetic activity (both cardiac and vascular) and a shift towards cardiac parasympathetic predominance have been recorded.7 In contrast, immersion in slightly cold water (temperature 25°C–30°C), leads to sympathetic vascular and parasympathetic cardiac hyperactivity. 8 Despite these limitations, the findings of Rodriguez et al are interesting. The greater post exercise decrease in blood pressure recorded in untrained healthy women after walking in chest-deep water in comparison with walking on land suggests an enhancement of the cardiovascular outcomes of exercise in water. Furthermore, this study can be considered to be relevant to assessments made in real clinical practice. Indeed, rehabilitation programs are frequently performed in swimming pools at water temperatures below thermoneutral conditions (between 28°C and 31°C). Further studies are needed to assess the benefit of water exercises in the management of cardiac patients.

Nailfold capillaroscopy and blood flow laser-doppler analysis of the microvascular damage in systemic sclerosis: preliminary results

Systemic sclerosis (SSc) is characterized by altered microvascular structure and function. Nailfold videocapillaroscopy (NVC) is the tool to evaluate capillary morphological structure and laser-Doppler Blood flowmetry (LDF) can be used to estimate cutaneous blood flow of microvessels. The aim of this study was to investigate possible relationships between capillary morphology and blood flow in SSc. Twenty-seven SSc patients and 12 healthy subjects were enrolled. SSc microvascular involvement, as evaluated by NVC, was classified in three different patterns ("Early", "Active", "Late"). LDF analysis was performed at the II, III, IV, V hand fingers in both hands and both at cutaneous temperature and at 36 degrees C. Statistical evaluation was carried out by non-parametric procedures. Blood flow was found significantly lower in SSc patients when compared with healthy subjects (p<0.05). The heating of the probe to 36 degrees C induced a significant increase in peripheral blood flow in all subjects compared to baseline (p <0.05), however, the amount of variation was significantly lower in patients with SSc, compared with healthy controls (p <0.05). The SSc patients with NVC "Late" pattern, showed lower values of peripheral blood flow than patients with NVC "Active" or "Early" patterns (p<0.05). Moreover, a negative correlation between the tissue perfusion score and the progression of the SSc microangiopathy was observed, as well as between the tissue perfusion and the duration of the Raynaud's phenomenon (p <0.03). LDF can be employed to evaluate blood perfusion in the microvascular circulation in SSc patients. The blood flow changes observed with the LDF seem to correlate with the severity of microvascular damage in SSc as detected by NVC.

Application of a Heat- and Steam-Generating Sheet Increases Peripheral Blood Flow and Induces Parasympathetic Predominance

To promote the practical application of a Japanese traditional medical treatment, such as hot compresses, we developed a plaster-type warming device consisting of a heat- and steam-generating sheet (HSG sheet). First, we tested its effects when applied to the anterior abdominal wall or lumbar region of women complaining of a tendency towards constipation. Application of the sheet to either region produced a feeling of comfort in the abdomen, as assessed by a survey of the subjects. The significant increases in the total hemoglobin observed in these regions suggested an increase in peripheral blood flow, and significant increases in the HF component on ECG and in the amplitude of gastric motility suggested parasympathetic predominance. We concluded that application of the HSG sheet improves the peripheral hemodynamics and autonomic regulation, induces a feeling of comfort in the abdomen, and provides a beneficial environment for the improvement of gastrointestinal movements.

Ambulante CT-gestützte thorakale Sympathikusblockade als zusätzliche Therapieoption bei komplexem regionalen Schmerzsyndrom Typ I nach Sportverletzungen

Also after bagatelle trauma, some patients can develop a complex regional pain syndrome (CRPS). The limb concerned usually shows a marked temperature difference to the contralateral side. Apart from a doughy swelling, the patient is impaired in particular by burning pain and a restricted range of motion. The objective of the present study was to examine the influence of early thoracic sympathetic nerve blockade on the basis of clinical and quantified blood flow parameters. In 7 young patients (average age 17.7 [15 - 21] years) with a clinically developing type 1 CRPS after sport injuries (mountain bike, bike, skateboard, hockey and go-kart accidents), occult injury and ligament lesions were ruled out using conventional imaging and MRI. In addition to pain-adapted physiotherapy and pharmacotherapy with analgesics and calcitonin, sympathetic nerve blockade was performed three times at two-day intervals. The CT-assisted puncture was performed in the prone position at the level of the intervertebral space of the 2nd/3 rd thoracic vertebral bodies. In the correct paravertebral position, a 10-cm long, 22 G Seibel-Grönemeier needle was used for the successive injection of 6 - 10 ml Carbostesin 0.5 %. By adding a small amount of contrast medium, it was possible to visualise clearly the distribution of the sympathicolytic agent in the control scan in each case. Before and after the intervention, colour-coded duplex sonography (CCDS) of the affected limb arteries was performed on all patients. The injection needle was correctly placed in all patients, without complications. The medication mixture was observed to have distributed properly. After the intervention, all patients reported the immediate onset of marked pain relief, whereby they recovered fully over the further course. The increase in peripheral blood flow was shown by a significant improvement in flow in the CCDS. Outpatient CT-assisted temporary sympathetic nerve blockade is an effective and low-complication therapeutic option for the supportive treatment of patients with CRPS.

Ingestion of bonito extract ameliorates peripheral blood flow in mice loaded from over crowding stress

Bonito extract (BE) has been shown to improve various fatigue-related symptoms. The possibility that the improvement of blood flow contributes to the improvement of fatigue-related symptoms has been reported. However, even though BE has been found to increase peripheral blood flow in humans, an understanding of its mechanisms has remained elusive. The purpose of the present study is to construct an animal model system with which the blood flow-increasing effects of BE can be examined. Using mice loaded with crowding stress, an attempt was made to reproduce the increases in peripheral blood flow observed in humans after a single administration of BE. In this study, the crowded-condition mice (20 mice/cage) showed significantly increased catecholamine levels (noradrenaline, adrenaline, and dopamine) in their circulating blood and a decreased rate of skin blood perfusion in comparison with the normal-condition mice (6 mice/cage). The rate of skin blood perfusion was significantly increased by BE in the crowded-condition mice in comparison with the controls, but not influenced by BE in the normal-condition mice. This suggests that BE expands the vascular diameter by affecting the constriction of vessels induced by catecholamines.

Ambulante CT-gestützte thorakale Sympathikusblockade als zusätzliche Therapieoption bei komplexem regionalen Schmerzsyndrom Typ I nach Sportverletzungen

Also after bagatelle trauma, some patients can develop a complex regional pain syndrome (CRPS). The limb concerned usually shows a marked temperature difference to the contralateral side. Apart from a doughy swelling, the patient is impaired in particular by burning pain and a restricted range of motion. The objective of the present study was to examine the influence of early thoracic sympathetic nerve blockade on the basis of clinical and quantified blood flow parameters. In 7 young patients (average age 17.7 [15-21] years) with a clinically developing type 1 CRPS after sport injuries (mountain bike, bike, skateboard, hockey and go-kart accidents), occult injury and ligament lesions were ruled out using conventional imaging and MRI. In addition to pain-adapted physiotherapy and pharmacotherapy with analgesics and calcitonin, sympathetic nerve blockade was performed three times at two-day intervals. The CT-assisted puncture was performed in the prone position at the level of the intervertebral space of the 2nd/3rd thoracic vertebral bodies. In the correct paravertebral position, a 10-cm long, 22 G Seibel-Grönemeier needle was used for the successive injection of 6-10 ml Carbostesin 0.5 %. By adding a small amount of contrast medium, it was possible to visualise clearly the distribution of the sympathicolytic agent in the control scan in each case. Before and after the intervention, colour-coded duplex sonography (CCDS) of the affected limb arteries was performed on all patients. The injection needle was correctly placed in all patients, without complications. The medication mixture was observed to have distributed properly. After the intervention, all patients reported the immediate onset of marked pain relief, whereby they recovered fully over the further course. The increase in peripheral blood flow was shown by a significant improvement in flow in the CCDS. Outpatient CT-assisted temporary sympathetic nerve blockade is an effective and low-complication therapeutic option for the supportive treatment of patients with CRPS.

Effect of body temperature on cold induced vasodilation

Cold-induced vasodilation (CIVD) is an acute increase in peripheral blood flow observed during cold exposures. It is hypothesized to protect against cold injuries, yet despite continuous research it remains an unexplained phenomenon. Contrary to the traditionally held view, we propose that CIVD is a thermoregulatory reflex mechanism contributing to heat loss. Ten adults (4 females; 23.8 +/- 2.0 years) randomly underwent three 130-min exposures to -20 degrees C incorporating a 10-min moderate exercise period at the 65th min, while wearing a liquid conditioning garment (LCG) and military arctic clothing. In the pre-warming condition, rectal temperature was increased by 0.5 degrees C via the LCG before the cold exposure. In the warming condition, participants regulated the LCG throughout the cold exposure to subjective comfort. In the control condition, the LCG was worn but was not operated either before or during the cold exposure. Results demonstrated that the majority of CIVD occurred during the warming condition when the thermometrically-estimated mean body temperature (T (b)) was at its highest. A thermoregulatory pattern was identified whereby CIVD occurred soon after T (b) increased past a threshold (approximately 36.65 degrees C in warming and pre-warming; approximately 36.4 degrees C in control). When CIVD occurred, T (b) was reduced and CIVD ceased when T (b) fell below the threshold. These findings were independent of extremity temperature since CIVD episodes occurred at a large range of finger temperatures (7.2-33.5 degrees C). These observations were statistically confirmed by auto-regressive integrated moving average analysis (t = 9.602, P < 0.001). We conclude that CIVD is triggered by increased T (b) supporting the hypothesis that CIVD is a thermoregulatory mechanism contributing to heat loss.

Prostaglandin F2 increases endothelial nitric oxide synthase in the periphery of the bovine corpus luteum: the possible regulation of blood flow at an early stage of luteolysis

Prostaglandin F(2)(alpha) (PGF(2)(alpha)) released from the uterus causes alterations in luteal blood flow, reduces progesterone secretion, and induces luteolysis in the bovine corpus luteum (CL). We have recently discovered that luteal blood flow in the periphery of the mature CL acutely increases coincidently with pulsatile increases in a metabolite of PGF(2)(alpha) (PGFM). In this study, we characterized changes in regional luteal blood flow together with regional alterations in endothelial nitric oxide synthase (eNOS) expression during spontaneous luteolysis and in response to PGF(2)(alpha). Smooth muscle actin-positive blood vessels larger than 20 microm were observed mainly in the periphery of mature CL. PGF(2)(alpha) receptor was localized to luteal cells and large blood vessels in the periphery of mid-CL. PGF(2)(alpha) acutely stimulated eNOS expression in the periphery but not in the center of mature CL. Injection of the NO donor S-nitroso-N-acetylpenicillamine into CL induced an acute increase in luteal blood flow and shortened the estrous cycle. In contrast, injection of the NOS inhibitor l-NAME into CL completely suppressed the acute increase in luteal blood flow induced by PGF(2)(alpha) and delayed the onset of luteolysis. In conclusion, PGF(2)(alpha) has a site-restricted action depending on not only luteal phase but also the region in the CL. PGF(2)(alpha) stimulates eNOS expression, vasodilation of blood vessels, and increased luteal blood flow in periphery of mature CL. Furthermore, the increased blood flow is mediated by NO, suggesting that the acute increase in peripheral blood flow to CL is one of the first physiological indicators of NO action in response to PGF(2)(alpha).

Exercise training in heart failure: reduction in angiotensin II, sympathetic nerve activity, and baroreflex control

neurohumoral excitation has been considered the hallmark of heart failure. At the humoral level, cardiac dysfunction has been shown to be associated with increased angiotensin II, aldosterone, and vasopressin levels. The clinical implication for such humoral dysregulation is the increase in salt and

Adaptations in autonomic function during exercise training in heart failure

Although neurohumoral excitation is the hallmark of heart failure (HF), the mechanisms underlying this alteration are not entirely known. Abnormalities in several systems contribute to neurohumoral excitation in HF, including arterial and cardiopulmonary baroreceptors, central and peripheral chemoreceptors, cardiac chemoreceptors, and central nervous system abnormalities. Exercise intolerance is characteristic of chronic HF, and growing evidence strongly suggests that exercise limitation in patients with chronic HF is not due to elevated filling pressures or inadequate cardiac output during exercise, but instead due to skeletal myopathy. Several lines of evidence suggest that sympathetic excitation contributes to the skeletal myopathy of HF, since sympathetic activity mediates vasoconstriction at rest and during exercise likely restrains muscle blood flow, arteriolar dilatation, and capillary recruitment, leading to underperfused areas of working muscle, and areas of muscle ischemia, release of reactive oxygen species (ROS), and inflammation. Although controversial, either unmyelinated, metabolite-sensitive afferent fibers, and/or myelinated, mechanosensitive afferent fibers in skeletal muscle underlie the exaggerated sympathetic activity in HF. Exercise training has emerged as a unique non-pharmacological strategy for the treatment of HF. Regular exercise improves functional capacity and quality of life, and perhaps prognosis in chronic HF patients. Recent studies have provided convincing evidence that these benefits in chronic HF patients are mediated by significant reduction in central sympathetic outflow as a consequence of improvement in arterial and chemoreflex controls, and correction of central nervous system abnormalities, and increase in peripheral blood flow with reduction in cytokines and increase in mass muscle.