Effect of Prostaglandins A1, A2, B1, E2 and F2α on Forearm Arterial Bed and Superficial Hand Veins in Man

1973 ◽  
Vol 44 (4) ◽  
pp. 367-376 ◽  
Author(s):  
B. F. Robinson ◽  
J. G. Collier ◽  
S. M. M. Karim ◽  
K. Somers
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Brachial Artery ◽  
Peripheral Blood ◽  
Forearm Blood Flow ◽  
The Other ◽  
Dose Dependent Increase ◽  
Dose Dependent

1. The effects of local infusions of prostaglandins (PG) A1, A2, B1, E2 and F2α have been studied in the forearm arterial bed and superficial hand veins of man. 2. Prostaglandins A1, A2, B1, E2 and F2α all gave rise to a dose-dependent increase in forearm blood flow when infused into the brachial artery. At dosages just below the dilator range, PGF2α caused a transient fall in forearm flow, but this was not seen with any of the other prostaglandins. 3. Prostaglandins A1, A2 and E2 had no effect when infused locally into relaxed veins but caused dose-dependent dilatation when given into veins preconstricted with either noradrenaline or 5-hydroxytryptamine. Prostaglandins B1 and F2α caused dose-dependent constriction when given into relaxed veins and had no dilator effect when infused into preconstricted veins. 4. The results suggest that there are at least two types of receptors mediating responses to prostaglandins in peripheral blood vessels.

Age-independent forearm vasodilatation by acetylcholine and adenosine 5′-triphosphate in humans

1990 ◽  
Vol 78 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Tsutomu Imaizumi ◽  
Akira Takeshita ◽  
Satoshi Suzuki ◽  
Megumu Yoshida ◽  
Shinichi Ando ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Sodium Nitroprusside ◽  
Vascular Resistance ◽  
Brachial Artery ◽  
Forearm Blood Flow ◽  
Resistance Arteries ◽  
Dose Dependent ◽  
Forearm Vascular Resistance ◽  
Age Independent

1. Forearm vasodilator responses to acetylcholine, ATP and sodium nitroprusside were examined in healthy young (20 ± 1 years, n = 9), middle-aged (46 ± 2 years, n = 6) and old (57 ± 1 years, n = 6) subjects. 2. A brachial artery was cannulated with a 20-gauge cannula through which drugs at graded doses were locally infused for 2 min at each dose. During drug infusions, forearm blood flow was continuously measured at 15 s intervals using a plethysmograph. Forearm vascular resistance was calculated from forearm blood flow and mean blood pressure obtained in the opposite arm. Basal forearm blood flow and forearm vascular resistance did not differ between the three groups. 3. Acetylcholine and ATP were used to examine endothelium-dependent vasodilatation, and sodium nitroprusside was used to examine endothelium-independent vasodilatation. All three drugs caused dose-dependent increases in forearm blood flow (P < 0.01) and decreases in forearm vascular resistance (P < 0.01). The increases in forearm blood flow or decreases in forearm vascular resistance in response to infusions of the three drugs did not differ between the three groups. 4. These results suggest that endothelium-dependent and endothelium-independent vasodilatation in forearm resistance arteries do not alter with ageing in humans.

Failure of prostaglandins to modulate the time course of blood flow during dynamic forearm exercise in humans

1996 ◽  
Vol 81 (4) ◽  
pp. 1516-1521 ◽  
Author(s):  
J. K. Shoemaker ◽  
H. L. Naylor ◽  
Z. I. Pozeg ◽  
R. L. Hughson
Keyword(s):  
Blood Flow ◽  
Brachial Artery ◽  
Time Course ◽  
Forearm Blood Flow ◽  
Voluntary Contraction ◽  
Double Blind ◽  
Rate Of Increase ◽  
Forearm Exercise ◽  
Blind Manner ◽  
Exercise In Humans

Shoemaker, J. K., H. L. Naylor, Z. I. Pozeg, and R. L. Hughson. Failure of prostaglandins to modulate the time course of blood flow during dynamic forearm exercise in humans. J. Appl. Physiol. 81(4): 1516–1521, 1996.—The time course and magnitude of increases in brachial artery mean blood velocity (MBV; pulsed Doppler), diameter ( D; echo Doppler), mean perfusion pressure (MPP; Finapres), shear rate (γ˙ = 8 ⋅ MBV/ D), and forearm blood flow (FBF = MBV ⋅ π r 2) were assessed to investigate the effect that prostaglandins (PGs) have on the hyperemic response on going from rest to rhythmic exercise in humans. While supine, eight healthy men performed 5 min of dynamic handgrip exercise by alternately raising and lowering a 4.4-kg weight (∼10% maximal voluntary contraction) with a work-to-rest cycle of 1:1 (s/s). When the exercise was performed with the arm positioned below the heart, the rate of increase in MBV and γ˙ was faster compared with the same exercise performed above the heart. Ibuprofen (Ibu; 1,200 mg/day, to reduce PG-induced vasodilation) and placebo were administered orally for 2 days before two separate testing sessions in a double-blind manner. Resting heart rate was reduced in Ibu (52 ± 3 beats/min) compared with placebo (57 ± 3 beats/min) ( P < 0.05) without change to MPP. With placebo, D increased in both arm positions from ∼4.3 mm at rest to ∼4.5 mm at 5 min of exercise ( P < 0.05). This response was not altered with Ibu ( P > 0.05). Ibu did not alter the time course of MBV or forearm blood flow ( P > 0.05) in either arm position. The γ˙ was significantly greater in Ibu vs. placebo at 30 and 40 s of above the heart exercise and for all time points after 25 s of below the heart exercise ( P < 0.05). Because PG inhibition altered the time course ofγ˙ at the brachial artery, but not FBF, it was concluded that PGs are not essential in regulating the blood flow responses to dynamic exercise in humans.

Adenosine contributes to hypoxia-induced forearm vasodilation in humans

1999 ◽  
Vol 87 (6) ◽  
pp. 2218-2224 ◽  
Author(s):  
Urs A. Leuenberger ◽  
Kris Gray ◽  
Michael D. Herr
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Brachial Artery ◽  
Adenosine Receptors ◽  
Forearm Blood Flow ◽  
Minute Ventilation ◽  
Acute Hypoxia ◽  
Normal Subjects ◽  
Local Release ◽  
Forearm Vascular Resistance

In humans, hypoxia leads to increased sympathetic neural outflow to skeletal muscle. However, blood flow increases in the forearm. The mechanism of hypoxia-induced vasodilation is unknown. To test whether hypoxia-induced vasodilation is cholinergically mediated or is due to local release of adenosine, normal subjects were studied before and during acute hypoxia (inspired O210.5%; ∼20 min). In experiment I, aminophylline (50–200 μg ⋅ min−1 ⋅ 100 ml forearm tissue−1) was infused into the brachial artery to block adenosine receptors ( n = 9). In experiment II, cholinergic vasodilation was blocked by atropine (0.4 mg over 4 min) infused into the brachial artery ( n = 8). The responses of forearm blood flow (plethysmography) and forearm vascular resistance to hypoxia in the infused and opposite (control) forearms were compared. During hypoxia (arterial O2 saturation 77 ± 2%), minute ventilation and heart rate increased while arterial pressure remained unchanged; forearm blood flow rose by 35 ± 6% in the control forearm but only by 5 ± 8% in the aminophylline-treated forearm ( P < 0.02). Accordingly, forearm vascular resistance decreased by 29 ± 5% in the control forearm but only by 9 ± 6% in the aminophylline-treated forearm ( P < 0.02). Atropine did not attenuate forearm vasodilation during hypoxia. These data suggest that adenosine contributes to hypoxia-induced vasodilation, whereas cholinergic vasodilation does not play a role.

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.

scholarly journals Arbutin Content and Tyrosinase Activity of Bergenia Extracts

2017 ◽  
Vol 12 (4) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Lenka Tůmová ◽  
Iva Dolečková ◽  
Helena Hendrychová ◽  
Marie Kašparová
Keyword(s):  
Tyrosinase Activity ◽  
The Other ◽  
Aqueous Extracts ◽  
Other Hand ◽  
Ethanol Extracts ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Diphenolase Activity

The total arbutin content in the leaves of all the studied Bergenia plants ( B. crassifolia, B. ciliata and B. x ornata) was determined. The highest values of the arbutin content have been established for B. crassifolia (58.9 ± 0.7 mg.g−1 DW) and B. x ornata (51.0 ± 1.21 mg.g−1 DW), and the lowest for B. ciliata (5.9 ± 0.6 mg.g−1 DW). Arbutin concentration in the Bergenia leaves was the lowest in spring, in the autumn, on the contrary it increased. All the tested aqueous extracts caused a dose-dependent increase in diphenolase activity of fungal tyrosinase in a similar way as arbutin. On the other hand, all the ethanol extracts inhibited the diphenolase activity of tyrosinase.

Dose-Dependent Effects of Meclofenamate on Peripheral Vasculature of Conscious Rabbits

1983 ◽  
Vol 64 (5) ◽  
pp. 471-474 ◽  
Author(s):  
R. A. Banks ◽  
L. J. Beilin ◽  
J. Soltys
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Organ Blood Flow ◽  
Hepatic Circulation ◽  
Peripheral Vasculature ◽  
Conscious Rabbits ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
The Brain ◽  
Intravenous Sodium

1. Changes in systemic haemodynamics and organ blood flow were measured in conscious rabbits after various doses of intravenous sodium meclofenamate, an inhibitor of prostaglandin cyclo-oxygenase. 2. Meclofenamate had no effect on arterial pressure or cardiac output but caused a dose-dependent fall in renal blood flow. 3. Meclofenamate also reduced adrenal perfusion but, in contrast, caused a dose-dependent increase in blood flow to the brain, bronchial and hepatic circulation and to the testis. No effect was demonstrated on other organs studied. 4. The effect on the cerebral circulation was observed at the lowest dose of meclofenamate (0.75 mg/kg). Higher total doses were necessary for an effect on the renal and bronchial (3 mg/kg) and testicular and hepatic arteries (6 mg/kg). 5. The results suggest a variety of local vasomotor influences of renal and non-renal prostaglandins in conscious rabbits.

scholarly journals Dose-Dependent Increase in Unconjugated Cinnamic Acid Concentration in Plasma Following Consumption of Polyphenol Rich Curry in the Polyspice Study

2018 ◽  
Author(s):  
Sumanto Haldar ◽  
Sze Han Lee ◽  
Jun Jie Tan ◽  
Siok Ching Chia ◽  
Christiani Jeyakumar Henry ◽  
...  
Keyword(s):  
Crossover Study ◽  
Phenolic Acids ◽  
Cinnamic Acid ◽  
Phenylacetic Acid ◽  
Plasma Concentrations ◽  
The Other ◽  
High Dose ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Randomized Crossover Study

Spices rich in polyphenols are metabolized to a convergent group of phenolic acids. We conducted a dose-exposure nutrikinetic study to investigate associations between mixed spices intake and plasma concentrations of selected, unconjugated phenolic acids. In a randomized crossover study, 20 Chinese males consumed a curry meal containing 0 g, 6 g, and 12 g of mixed spices. Postprandial blood was drawn up to 7 h at regular intervals and plasma phenolic acids were quantified via LC-MS/MS. Cinnamic acid (CNA, p &lt; 0.0001) and phenylacetic acid (PAA, p &lt; 0.0005) concentrations were significantly increased with mixed spices consumption, although none of the other measured phenolic acids differ significantly between treatments. CNA displayed a high dose-exposure association (R2 &gt; 0.8, p &lt; 0.0001). The adjusted mean AUC0-7 h for CNA during the 3 increasing doses were 8.4 &plusmn; 3.4, 376.1 &plusmn; 104.7 and 875.7 &plusmn; 291.9 nM&middot;h respectively. Plasma CNA concentration may be used as a biomarker of spice intake.

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