scholarly journals The role of skin and muscle vessels in the response of forearm blood flow to noradrenaline

1964 ◽  
Vol 173 (1) ◽  
pp. 65-73 ◽  
Author(s):  
C. J. Cooper ◽  
J. D. Fewings ◽  
R. L. Hodge ◽  
G. C. Scroop ◽  
R. F. Whelan
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow

Effect of nerve block on response of forearm blood flow to local temperature

1986 ◽  
Vol 61 (1) ◽  
pp. 227-232 ◽  
Author(s):  
C. B. Wenger ◽  
L. A. Stephenson ◽  
M. A. Durkin
Keyword(s):  
Blood Flow ◽  
Nerve Block ◽  
Forearm Blood Flow ◽  
Brachial Plexus Block ◽  
Thermal Sensation ◽  
Strain Gauges ◽  
Forearm Skin ◽  
Plastic Bag ◽  
Plexus Block

To determine the role of neurotransmitter in the response of forearm blood flow (ABF) to local (forearm) skin temperature (Tsk) we measured ABF of six subjects at Tsk from 25 to 40 degrees C before (control) and after brachial plexus block (BPB). Control experiments were conducted in an ambient temperature of 27–29 degrees C, adjusted to minimize the subject's overall thermal sensation. Tsk was regulated by blowing a controlled-temperature airstream through a plastic bag enclosing the arm. We first lowered Tsk to 25 degrees C and after 20 min began to measure ABF with Whitney strain gauges. We then raised Tsk by 2.5 degrees C steps to 40 degrees C and measured ABF every 30 s for at least 10 min at each level of Tsk. Mean ABF rose from 1.1 ml X 100 ml-1 X min-1 at Tsk of 25 degrees C to 2.1 ml X 100 ml-1 X min-1 at 32.5 degrees C to 13.7 ml X 100 ml-1 X min-1 at 40 degrees C in control experiments and from 2.8 to 4.4 to 14.8 ml X 100 ml-1 X min-1 after BPB. The effect of Tsk on ABF was highly significant (P less than 0.0001) but the effect of BPB was not (P approximately equal to 0.2). At thermoneutrality, the effect of Tsk on ABF is largely independent of neural activity, since this effect is unaffected by nerve block.

Role of Nitric Oxide towards Vasodilator Effects of Substance P and ATP in Human Forearm Vessels

1997 ◽  
Vol 92 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Masanari Shiramoto ◽  
Tsutomu Imaizumi ◽  
Yoshitaka Hirooka ◽  
Toyonari Endo ◽  
Takashi Namba ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Substance P ◽  
Sodium Nitroprusside ◽  
Forearm Blood Flow ◽  
Dependent Manner ◽  
Human Forearm ◽  
Before And After ◽  
Dose Dependent

1. It has been shown in animals that substance P as well as acetylcholine releases endothelium-derived nitric oxide and evokes vasodilatation and that ATP-induced vasodilatation is partially mediated by nitric oxide. The aim of this study was to examine whether vasodilator effects of substance P and ATP are mediated by nitric oxide in humans. 2. In healthy volunteers (n = 35), we measured forearm blood flow by a strain-gauge plethysmograph while infusing graded doses of acetylcholine, substance P, ATP or sodium nitroprusside into the brachial artery before and after infusion of NG-monomethyl-l-arginine (4 or 8 μmol/min for 5 min). In addition, we measured forearm blood flow while infusing substance P before and during infusion of l-arginine (10 mg/min, simultaneously), or before and 1 h after oral administration of indomethacin (75 mg). 3. Acetylcholine, substance P, ATP or sodium nitroprusside increased forearm blood flow in a dose-dependent manner. NG-Monomethyl-l-arginine decreased basal forearm blood flow and inhibited acetylcholine-induced vasodilatation but did not affect substance P-, ATP-, or sodium nitroprusside-induced vasodilatation. Neither supplementation of l-arginine nor pretreatment with indomethacin affected substance P-induced vasodilatation. 4. Our results suggest that, in the human forearm vessels, substance P-induced vasodilatation may not be mediated by either nitric oxide or prostaglandins and that ATP-induced vasodilatation may also not be mediated by nitric oxide.

Haemodynamic Effects of Eating: The Role of Meal Composition

1996 ◽  
Vol 90 (4) ◽  
pp. 269-276 ◽  
Author(s):  
U. Høst ◽  
H. Kelbaek ◽  
H. Rasmusen ◽  
M. Court-Payen ◽  
N. Juel Christensen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Portal Vein ◽  
Forearm Blood Flow ◽  
Plasma Catecholamines ◽  
Left Ventricular ◽  
Gastric Distension ◽  
Left Ventricular Volumes ◽  
Portal Vein Flow

1. The purpose of this study was to investigate the effect of fractional meal stimulation on postprandial haemodynamic changes, the possible correlation between these changes and the potential mediating role of circulating catecholamines and insulin. 2. Healthy young subjects were studied before and after ingestion of isocaloric, isovolumetric high-protein, carbohydrate or fat meals (80–85% of total energy), 60 kJ per kg of body weight. Multigated radionuclide cardiography with autologous 99mTc-labelled erythrocytes was performed for assessment of cardiac output, venous occlusion plethysmography to obtain forearm blood flow and Doppler-ultrasonography for portal vein flow. Plasma levels of catecholamines and insulin were determined by radioimmunoassay. 3. Cardiac output increased considerably after each meal, including the control meal (water) with only minor differences in extent and timing. Left ventricular volumes increased after food intake, most pronounced after carbohydrate and protein. Forearm blood flow increased only after carbohydrate and protein. Portal vein flow increased after all meals, especially after fat, but also after the control meal. There was a significant correlation between the increment in cardiac output and changes in forearm and portal vein flow, but no correlation between either haemodynamic response and plasma catecholamines or insulin. 4. Postprandial cardiovascular changes are not substantially different after various isocaloric and isovolumic meal compositions. Gastric distension seems to play a role in the increase in cardiac output, accomplished by ventricular dilatation. These changes seem to some extent to be linked to changes in muscle and splanchnic flow.

Inhibition of vascular ATP-sensitive K+channels does not affect reactive hyperemia in human forearm

2003 ◽  
Vol 284 (2) ◽  
pp. H711-H718 ◽  
Author(s):  
H. M. Omar Farouque ◽  
Ian T. Meredith
Keyword(s):  
Blood Flow ◽  
Adaptive Response ◽  
Healthy Subjects ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Venous Occlusion ◽  
Channel Inhibition ◽  
Human Forearm ◽  
Hyperemic Response

The extent to which ATP-sensitive K+ channels contribute to reactive hyperemia in humans is unresolved. We examined the role of ATP-sensitive K+channels in regulating reactive hyperemia induced by 5 min of forearm ischemia. Thirty-one healthy subjects had forearm blood flow measured with venous occlusion plethysmography. Reactive hyperemia could be reproducibly induced ( n = 9). The contribution of vascular ATP-sensitive K+ channels to reactive hyperemia was determined by measuring forearm blood flow before and during brachial artery infusion of glibenclamide, an ATP-sensitive K+ channel inhibitor ( n = 12). To document ATP-sensitive K+ channel inhibition with glibenclamide, coinfusion with diazoxide, an ATP-sensitive K+ channel opener, was undertaken ( n = 10). Glibenclamide did not significantly alter resting forearm blood flow or the initial and sustained phases of reactive hyperemia. However, glibenclamide attenuated the hyperemic response induced by diazoxide. These data suggest that ATP-sensitive K+ channels do not play an important role in controlling forearm reactive hyperemia and that other mechanisms are active in this adaptive response.

Effect of Captopril on Glucose Concentration: Possible Role of Augmented Postprandial Forearm Blood Flow

Diabetes Care ◽  
1990 ◽  
Vol 13 (11) ◽  
pp. 1109-1111 ◽  
Author(s):  
J. Kodama ◽  
S. Katayama ◽  
K. Tanaka ◽  
A. Itabashi ◽  
S. Kawazu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Glucose Concentration ◽  
Forearm Blood Flow

Venous Constriction in Response to Head-Up Tilt in Man

1972 ◽  
Vol 50 (4) ◽  
pp. 317-320 ◽  
Author(s):  
Lars O. Boréus ◽  
Norman K. Hollenberg
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Marked Decrease ◽  
Technical Difficulty ◽  
Venous Occlusion ◽  
Venous System ◽  
Postural Stress ◽  
Venous Distensibility ◽  
Head Up Tilt

There has been disagreement about the role of the peripheral venous system in cardiovascular adjustments to postural stress in man. In part this seems to be due to the technical difficulty in determining venous distensibility by plethysmographic techniques in situations where concomitant changes in blood flow occur. We have demonstrated in this study that rapid and consistent increases in forearm venous tone assessed by venous occlusion plethysmography do occur on head-up tilt in man, and that they can be readily masked by the parallel marked decrease in forearm blood flow. It is concluded that the peripheral venous system in man is not designed to function only in states of severe stress but rather plays an important role in moment-to-moment adjustments of cardiovascular activity.

Otolithic and tonic neck receptors control of limb blood flow in humans

1997 ◽  
Vol 82 (6) ◽  
pp. 1734-1738 ◽  
Author(s):  
Hervé Normand ◽  
Olivier Etard ◽  
Pierre Denise
Keyword(s):  
Blood Flow ◽  
Cardiovascular System ◽  
Forearm Blood Flow ◽  
Head Position ◽  
Limb Blood Flow ◽  
Significant Difference ◽  
Head Flexion ◽  
Head Positions ◽  
Flexion And Extension

Normand, Hervé, Olivier Etard, and Pierre Denise.Otolithic and tonic neck receptors control of limb blood flow in humans. J. Appl. Physiol. 82(6): 1734–1738, 1997.—The aim of this study was to evaluate the role of otolithic receptors and neck mechanoreceptors on the control of the cardiovascular system. We measured calf (CBF) and forearm blood flow (FBF) by strain-gauge plethysmography, mean arterial pressure (MAP), and heart rate (HR) in 12 healthy subjects in two body positions (lying prone and on the left side) and three head positions (reference, flexion, and extension). When the subjects were lying prone, CBF and FBF were lower in head flexion (5.2 ± 0.6 and 3.2 ± 0.4 ml ⋅ min−1 ⋅ 100 ml−1, respectively) than in reference position (5.8 ± 0.4 and 3.8 ± 0.3 ml ⋅ min−1 ⋅ 100 ml−1; P < 0.05), with no significant difference in MAP and HR. When the subjects were lying on the side, changing the head position from reference to flexion significantly increased FBF (from 3.7 ± 0.2 to. 4.2 ± 0.4 ml ⋅ min−1 ⋅ 100 ml−1), MAP (from 97.2 ± 3.3 to 102.4 ± 5.8 mmHg), and HR (from 63.7 ± 1.4 to 65.9 ± 2.5 beats/min; P < 0.05). Because otolithic receptors and neck mechanoreceptors are involved when the subjects are lying prone, and otolithic receptors are not involved when the subjects are lying on the side, the results suggest that otolithic and neck mechanoreceptors exert significant influences over the cardiovascular system.

scholarly journals Continuous release of vasodilator prostanoids contributes to regulation of resting forearm blood flow in humans

1998 ◽  
Vol 274 (4) ◽  
pp. H1174-H1183 ◽  
Author(s):  
Stephen J. Duffy ◽  
Binh T. Tran ◽  
Gishel New ◽  
Ronald N. Tudball ◽  
Murray D. Esler ◽  
...  
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Venous Occlusion ◽  
Continuous Release ◽  
Before And After ◽  
Prostaglandin F ◽  
Resting Tone ◽  
Dose Dependent ◽  
Prostacyclin Production

Continuous release of nitric oxide contributes to the maintenance of resting tone in the human forearm and coronary circulations; however, evidence for a similar role of vasodilator prostanoids such as prostacyclin is lacking. We examined whether continuous release of prostacyclin contributes to basal forearm blood flow. Flow was measured using venous occlusion plethysmography in 38 healthy volunteers [mean age 21.3 ± 2.5 yr (±SD); 13 female, 25 male] at rest, after administration of three incremental intra-arterial infusions of either the cyclooxygenase inhibitor aspirin or placebo, and before and after administration of the endothelium-dependent and -independent dilators acetylcholine (30 μg/min) and nitroprusside (1 μg/min). To assess the effect of aspirin on the production of prostacyclin, plasma 6-keto prostaglandin F1α(6-keto-PGF1α; the stable metabolite of prostacyclin) was measured by simultaneous arterial and venous sampling. Aspirin produced a time- and dose-dependent reduction in forearm blood flow, resulting in a 32% decrease at the highest dose. The effect was maximal after 10 min. Flow at rest and after aspirin doses of 1, 3, and 10 mg/min was 2.6 ± 0.2, 2.3 ± 0.2, 2.1 ± 0.2, and 1.8 ± 0.2 ml ⋅ 100 ml forearm tissue−1 ⋅ min−1, respectively (means ± SE, P< 0.001). Commensurate with these data, the net forearm production of 6-keto-PGF1α was 52.9 ± 16.4, 11.7 ± 8.6, 18.7 ± 8.5, and 12.0 ± 12.5 pg ⋅ 100 ml forearm tissue−1 ⋅ min−1 for the respective doses ( P = 0.04). No time-dependent reduction in flow was seen in subjects with vehicle infusion. Aspirin did not affect the responses to acetylcholine or nitroprusside. These data suggest that continuous release of prostacyclin plays a role in the maintenance of resting forearm blood flow. There appears to be a direct link between the reduction in flow with aspirin and inhibition of prostacyclin production.

Role of the wrist cuff in forearm plethysmography

1991 ◽  
Vol 80 (5) ◽  
pp. 413-417 ◽  
Author(s):  
Jacques Lenders ◽  
Geert-Jan Janssen ◽  
Paul Smits ◽  
Theo Thien
Keyword(s):  
Blood Flow ◽  
Room Temperature ◽  
Forearm Blood Flow ◽  
Large Range ◽  
Cuff Pressure ◽  
Venous Pressure ◽  
Systolic Pressure ◽  
Ambient Temperatures ◽  
The Difference

1. To determine whether a wrist cuff is necessary to measure the forearm blood flow correctly, we studied the effects of wrist cuff inflation to supra-venous and supra-systolic pressure values over a large range of forearm blood flow values: in the basal state, during post-occlusive hyperaemia of the hand, and during heating of the hand with warm air. Eleven healthy men participated, and the study was carried out at two different ambient temperatures of 20 and 25°C. 2. In the basal state, the measured forearm blood flow was lowest with the wrist cuff at supra-systolic pressure. With the wrist cuff at supra-venous pressure the forearm blood flow was also lower than with an uninflated cuff, but only significantly so when the basal forearm blood flow was higher (at a room temperature of 25°C). 3. During post-occlusive hyperaemia, inflating the wrist cuff to supra-systolic pressure produced the lowest forearm blood flow value at both room temperatures. In addition, with the wrist cuff at supra-venous pressure, forearm blood flow values were lower than with the uninflated cuff, but the supra-venous cuff pressure was clearly less efficient in excluding the hand blood flow than the supra-systolic cuff pressure. 4. During heating of the hand, both supra-systolic and supra-venous cuff pressures were effective in excluding the hand blood flow at both room temperatures. The forearm blood flow measured with the wrist cuff at supra-systolic pressure was lower than that measured with the wrist cuff at supra-venous pressure, but the difference was only significant at a room temperature of 20°C. 5. In conclusion, we have demonstrated that a wrist cuff at supra-systolic pressure is most appropriate for the exclusion of the hand circulation in order to measure the forearm blood flow correctly.

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